IPAC2013 - List of Keywords (kicker)

Paper	Title	Other Keywords	Page
MOPEA013	Radioactive Beam Accumulation for a Storage Ring Experiment with an Internal Target	target, electron, ion, injection	91
	F. Nolden, C. Dimopoulou, R. Grisenti, C.M. Kleffner, S.A. Litvinov, W. Maier, C. Peschke, P. Petri, U. Popp, M. Steck, H. Weick, D.F.A. Winters, T. Ziglasch GSI, Darmstadt, Germany
	A radioactive ⁵⁶Ni beam was successfully accumulated for an experiment with an internal hydrogen target at the storage ring ESR of GSI, Germany. The radioactive beam was produced and separated at the GSI fragment separator from a stable ⁵⁸Ni beam. About 6·10⁴ ⁵⁶Ni ions were injected into the ESR on a high relative momentum orbit. The beam was subjected to stochastic cooling, bunched and transported to a low relative momentum orbit where it was neither disturbed by the field of the partial aperture injection kicker nor by the fields of the stochastic cooling kickers. Slightly below this deposition momentum, the beam was accumulated and continuously cooled by means of electron cooling. For each experiment with internal hydrogen target, about 80 shots were injected consecutively, leading to a stored beam of roughly 5·10⁶ particles.

MOPEA016	The Main Stochastic Cooling System of the HESR	pick-up, accumulation, vacuum, simulation	100
	R. Stassen, R. Greven, R. Maier, G. Schug, H. Stockhorst FZJ, Jülich, Germany
	The main stochastic cooling system of the High-Energy Storage Ring HESR (1.5-15 GeV/c) for antiprotons at the FAIR complex (Facility for Antiprotons and Ion Research) in Darmstadt (GSI) will work in the frequency range of 2 - 4 GHz. The design work on pickup and kicker is now finished and the production of the first cooling tank has been started. The whole system layout will be presented taking into account new additional requirements concerning the accumulation and the cooling of heavy ions. All beam-coupling structures are nearly identical and contain several ring-slot blocks. These blocks consist of eight wall-current monitors coupled out by eight electrodes each. Most of the signal combining and splitting take place within the vacuum envelope to reduce the number of vacuum RF feed throughs. The long-distance transmission of the signals and the filters containing long signal delays work with near infrared optical elements.

MOPEA043	Transverse Instabilities of Two Twisted Beams in a Storage Ring	ion, electron, storage-ring, simulation	172
	B.C. Jiang, M.Z. Zhang, Z.T. Zhao SINAP, Shanghai, People's Republic of China G.X. Xia UMAN, Manchester, United Kingdom
	Two twisted beams (two beams run on the different closed orbit) in a storage ring which is produced by fast kickers can potentially deliver two bunds of radiations through one insertion device or one bend magnet, in this way doubles the beam line stations. This operation mode needs higher beam current and more RF buckets to be filled to keep the brightness comparable to the single beam operation mode. The resistive wall instability and ion trapping effects is analysed to address the higher current operation possibility. The analyze results show that twisted beams can weaken those two instabilities.

MOPEA055	First Year Operation of the ALBA Synchrotron Light Source	vacuum, storage-ring, interlocks, feedback	202
	F. Pérez CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain
	ALBA is a 3 GeV, 3rd generation, light source located in Cerdanyola, Barcelona, Spain, which started users operation in May 2012. In this paper we will report about the transition from commissioning to operation, the main problems faced during this first year, the actual status of the accelerators and we will provide an outlook to the next steps.

MOPEA059	The Optimization of Transverse Stripline Kicker	simulation, vacuum, impedance, insertion	214
	H.P. Hsueh, C.-C. Chang, Y.P. Chang, J.-R. Chen, Y.T. Cheng, G.-Y. Hsiung, Y.C. Yang NSRRC, Hsinchu, Taiwan J.-R. Chen National Tsing Hua University, Hsinchu, Taiwan
	The construction of a new 3 GeV synchrotron facility, Taiwan Photon Source, is ongoing. It is required to install stripline kickers to suppress instability generated by mismatch between injection kickers or imperfect installation of vacuum components all around. First, the design philosophy will be described for transverse stripline kickers. HFSS electromagnetic simulation software is used to optimize all structure parameters like electrode dimensions, electrode distance from vacuum chambers etc. to make transverse stripline kicker working more efficiently and effectively. All simulation results will be presented in this paper and all structure dimension choices will be discussed and the final prototype structure dimensions will be selected from the discussion.

MOPEA061	Operation Experience at Taiwan Light Source	SRF, cavity, diagnostics, injection	220
	Y.-C. Liu, H.H. Chen, H.C. Chen, S. Fann, S.J. Huang, J.A. Li, C.C. Liang, Y.K. Lin, Y.-H. Lin, M.-S. Yeh NSRRC, Hsinchu, Taiwan
	A matrix structure has been implemented for the purpose of successful operation of TLS and continuous progress of Taiwan Photon Source (TPS) construction. A dedicated and flexible manpower distribution has proven it could keep as same performance of TLS operation as possible. We will summarize the machine operation experience at TLS during TPS civil construction period.

MOPEA080	Status of the NSLS-II Injector	booster, linac, injection, storage-ring	273
	T.V. Shaftan, A. Blednykh, E.B. Blum, W.X. Cheng, J. Choi, L.R. Dalesio, M.A. Davidsaver, J.H. De Long, R.P. Fliller, G. Ganetis, F. Gao, A. Goel, W. Guo, K. Ha, R. Heese, H.-C. Hseuh, M.P. Johanson, B.N. Kosciuk, S. Kowalski, S.L. Kramer, Y. Li, W. Louie, S. Ozaki, D. Padrazo, J. Rose, S. Seletskiy, S.K. Sharma, G. Shen, O. Singh, V.V. Smaluk, Y. Tian, K. Vetter, W.H. Wahl, G.M. Wang, F.J. Willeke, X. Yang, L.-H. Yu, P. Zuhoski BNL, Upton, Long Island, New York, USA
	We discuss the current status and plans for developing the NSLS-II injector. The latter consists of a 200 MeV linac, a 3-GeV booster, transport lines and the storage ring injection straight section. The system design and installation are complete. Last year we concluded 200-MeV linac commissioning and are planning to commission the 3 GeV booster during summer of 2013.

MOPFI030	Study of the Beam Injection and Extraction of the Proton Irradiation Accelerator	injection, proton, extraction, synchrotron	348
	Y.W. An, H.F. Ji, S. Wang IHEP, Beijing, People's Republic of China
	The proton irradiation accelerator is widely founded for industry application, and the extracted beam is required to have large intensity as a pulse beam or uniform distribution for scanning. A multi-turn injection is adopted and the proton beam is injected into the ring with the energy of 10MeV. In order to increase injection beam intensity, local bump orbit including two-bump, three-bump and four-bump is well studied and optimized, and the septum magnet thickness and localization are also studied for an effective injection. A RF knock-out method is used for slow extraction due to the fast response character. In order to decrease the global spill, double RF kicker and the control of the aptitude modulation (AM) function of the transverse RF field are well studied.

MOPFI046	Transverse RF Kicker Excitation and Longitudinal RF Noise Diffusion for Slow Extraction from SAPT	extraction, simulation, synchrotron, resonance	386
	L. Ouyang, M. Gu, D.M. Li, Q. Yuan, M.Z. Zhang SINAP, Shanghai, People's Republic of China
	Two key techniques used in the slow extraction from synchrotron accelerator: longitudinal RF stochastic noise acceleration, and transverse RF knock out excitation have been studied in this paper. Detailed comparison have revealed the potentials and limits of both methods. For the longitudinal RF stochastic acceleration excitation, the focus has been the phase space compression of particles, which makes the them to hasten around the RF bucket of the cavity, thus to lower the senstivity to ripple. For the transverse RF knock out excitation, the emphasis have been optimal schemes of amplitude modulation and frequency modulation of the RF singals. The optimizations are also used to lower the senstivity of the beam to the ripple and to enhance the uniformity of the extracted beam.

MOPFI050	Non-local Fast Extraction from the CERN SPS at 100 and 440 GeV	extraction, simulation, septum, injection	392
	F.M. Velotti, A. Alekou, W. Bartmann, E. Carlier, K. Cornelis, I. Efthymiopoulos, B. Goddard, L.K. Jensen, V. Kain, M. Kowalska, V. Mertens, R. Steerenberg CERN, Geneva, Switzerland
	The Long Straight Section 2 (LSS2) of the CERN SPS is connected with the North Area (NA), to which the beam to date has always been extracted using a resonant extraction technique. For new proposed short- and long-baseline neutrino experiments, a fast single turn extraction to this experimental area is required. As there are no kickers in LSS2, and the integration of any new kickers with the existing electrostatic septum would be problematic, a solution has been developed to fast extract the beam using non-local extraction with other SPS kickers. Two different kicker systems have been used, the injection kicker in LSS1 and the stronger extraction kicker in LSS6 to extract 100 and 440 GeV beam, respectively. For both solutions a large emittance beam was extracted after 5 or 9 full betatron periods. The concept and simulation details are presented with the analysis of the aperture and beam loss considerations and experimental results collected during a series of beam tests.

MOPFI051	Beam Transfer Systems for the LAGUNA-LBNO Long Baseline Neutrino Beam from the CERN SPS	extraction, injection, target, septum	395
	B. Goddard, W. Bartmann, I. Efthymiopoulos, Y. Papaphilippou, A.S. Parfenova CERN, Geneva, Switzerland
	For the Long Baseline neutrino facility under study at CERN (LAGUNA-LBNO) it is initially planned to extract a 400 GeV beam from the second long straight section in the SPS into the existing transfer channel TT20 leading to the North Area experimental zone, to a new target aligned with a far detector in Finland. In a second phase a new High-Power Proton Synchrotron (HPPS) accelerator is proposed, to give a 2 MW beam at about 50 GeV on the same target. In this paper the beam transfer systems required for the project are outlined, including the new sections of transfer line between the SPL, HPPS and SPS, and from the SPS to the target, and also the injection and extraction systems in the long straight section of the HPPS. The feasibility of a 4 GeV H⁻ injection system is discussed.

MOPFI052	A New Lead Ion Injection System for the CERN SPS with 50 ns Rise Time	injection, ion, septum, impedance	398
	B. Goddard, O. Aberle, J. Borburgh, E. Carlier, K. Cornelis, L. Ducimetière, L.K. Jensen, T. Kramer, D. Manglunki, A. Mereghetti, V. Mertens, D. Nisbet, B. Salvant, L. Sermeus CERN, Geneva, Switzerland
	The LHC High Luminosity upgrade project includes a performance upgrade for heavy ions. One of the present performance limitations is the rise time of the SPS injection kicker system, which imposes a spacing of at least 220 ns between injected bunch trains at the operational rigidity. A reduction of this rise time to 50 ns for lead ions is requested as part of the suite of measures needed to increase the present design performance by a factor three. A new injection system based on a fast pulsed septum and a fast kicker has been proposed to fulfil this rise time requirement, and to meet all the constraints associated with the existing high intensity proton injection in the same region. This paper describes the concept and the required equipment parameters, and explores the implications of such a system for SPS operation.

MOPFI053	Upgrades of the SPS, Transfer Line and LHC Injection Protection Devices for the HL-LHC Era	injection, vacuum, coupling, extraction	401
	Ö. Mete, O. Aberle, F. Cerutti, K. Cornelis, B. Goddard, V. Kain, R. Losito, F.L. Maciariello, M. Meddahi, A. Mereghetti, J.A. Uythoven, F.M. Velotti CERN, Geneva, Switzerland E. Gianfelice-Wendt Fermilab, Batavia, USA
	The challenging High Luminosity LHC (HL-LHC) beam requirements will lead in the future to unprecedented beam parameters along the LHC injector chain. In the SPS accelerator these requests translate into about a factor two higher intensity and brightness than the present design performance. In addition to the challenge of producing and accelerating such beams, these parameters affect the resistance of the existing equipment against beam impact. Most of the protection devices in the SPS ring, its transfer lines and the LHC injection areas will be put under operational constraints which are beyond their design specification. The equipment concerned has been reviewed and their resistance to the HL-LHC beams checked. Theoretical and simulation studies have been performed for the SPS beam scraping system, the protection devices and the dump absorbers of the SPS-to-LHC transfer lines, as well as for the LHC injection protection devices. The first results of these studies are reported, together with the future prospects.

MOPFI054	Upgrades for the CERN PSB-TO-PS Transfer at 2 GeV	injection, optics, emittance, quadrupole	404
	W. Bartmann, J. Borburgh, J.R.T. Cole, S.S. Gilardoni, B. Goddard, O. Hans, M. Hourican, L. Sermeus, R. Steerenberg CERN, Geneva, Switzerland C.H. Yu IHEP, Beijing, People's Republic of China
	The CERN PS Booster extraction energy will be upgraded from 1.4 to 2.0 GeV to alleviate the direct space charge tune shift in the PS. The focussing structure of the transfer line will be modified in order to better match the optics between the PSB and the PS. The optics of the PS at injection and, with it, of the transfer line can be adapted to reduce the continuous losses from the already injected and circulating beam bumped towards the septum. Experimental results of the optics optimisation and probing the injection kicker gap will be shown.

MOPFI057	Studies for the LHeC Beam Transfer Systems	linac, injection, electron, extraction	410
	C. Bracco, B. Goddard CERN, Geneva, Switzerland
	The LHeC would allow for collisions between an electron beam from a new accelerator with the existing LHC hadron beam. Two possible configurations were studied: a separate LINAC (LINAC-ring) or a new electron ring superimposed on the LHC (ring-ring). The racetrack LINAC is now considered as the baseline for the LHeC design, with the ring-ring solution a back up. The studies performed for all the considered options are presented in this paper. For the LINAC-ring option the requirements for the post-collision line and the beam dump design have been evaluated in the cases of a 140 GeV and a 60 GeV electron beam. In the ring-ring option studies have been performed of the optics design of the transfer line from the a 10 GeV injector LINAC into the LHeC ring and of the injection system. The internal 60 GeV electron ring dump design has also been considered.

MOPFI061	Concept for Elena Extraction and Beam Transfer Elements	extraction, septum, quadrupole, vacuum	422
	J. Borburgh, B. Balhan, W. Bartmann, T. Fowler, L. Sermeus, G. Vanbavinckhove CERN, Geneva, Switzerland R.A. Baartman TRIUMF, Vancouver, Canada D. Barna University of Tokyo, Tokyo, Japan V. Pricop Transilvania University of Brasov, Brasov, Romania
	In 2011 the ELENA decelerator was approved as a CERN project. Initially one extraction was foreseen, which should use a kicker and a magnetic septum which can be recuperated from an earlier installation. Since then a second extraction has been approved and a new solution was studied using only electric fields to extract the beam. This will be achieved by fast pulsing a separator, allowing single-bunch but also a full single-turn extraction from ELENA towards the experiments. The extraction and transfer requirements of ELENA are described, followed by the principal differences between the magnetic and electric field concepts. The design of electrostatic focussing and bending devices for the transfer lines will be presented. Finally the field quality which can be achieved with the separator and the concept of its power supply will be discussed.

MOPME008	Beam Diagnostics by Using Bunch-by-bunch Feedback Systems at the DELTA Storage Ring	feedback, injection, laser, electron	485
	M. Höner, H. Huck, M. Huck, S. Khan, R. Molo, A. Schick, P. Ungelenk DELTA, Dortmund, Germany
	Funding: Work supported by BMBF (05K10PEB) At DELTA, a 1.5-GeV electron storage ring operated by the TU Dortmund University, longitudinal and transverse bunch-by-bunch feedback systems are in use to detect and suppress multi-bunch instabilities. Besides that, the digital feedback systems are excellent diagnostics tools. As an example, by exciting a certain number of bunches within the bunch train, the coupling to the non-excited bunches can be investigated below and above the instability threshold. Other examples include studies of the injection process and monitoring bunch oscillations during sudden beam loss. First experimental results will be presented in this paper.

MOPME018	BEAM OSCILLATION MONITOR FOR THE MULTI-BUNCH BEAM	damping, linac, wakefield, extraction	506
	T. Naito, S. Araki, H. Hayano, K. Kubo, S. Kuroda, T. Okugi, N. Terunuma, J. Urakawa KEK, Ibaraki, Japan
	In order to observe the motion of bunch-by-bunch beam oscillation of multi-bunch in the storage ring, we developed two measurement tools. One is a signal process electronics circuit using fast analogue switches. The circuit picks up one of the selected bunch signal of the beam position monitor from the multi-bunch. The selected beam position signal can be processed as a single bunch beam. By changing the gate timing, arbitrary bunch signal can be selected. The other is a waveform memory using a high bandwidth oscilloscope. The long waveform memory of the oscilloscope has a capability to acquire the multi-turn waveform of the button electrode signals. The beam test of the circuit has been carried out at KEK-ATF damping ring in the cases of 2.8ns bunch spacing and 5.6ns bunch spacing, respectively. The detail of the hardware and the result of the beam test are reported.

MOPME025	Production of Extraction Kicker Magnet of the J-PARC 3-GeV RCS	vacuum, high-voltage, extraction, proton	526
	M. Kinsho, N. Ogiwara, K. Suganuma JAEA/J-PARC, Tokai-mura, Japan
	The J-PARC 3-GeV rapid cycling synchrotron (RCS) has been provided proton beam to the Material and Life Science Facility (MLF)as well as to the 50 GeV Main Ring (MR). Proton beam is accelerated from 181 MeV to 3GeV in the RCS and immediately extracted it to the beam transport line to the MLF and the MR. Extraction kicker magnets are used for this fast extraction. To improve reliability of the RCS for user operation, production of a reserve kicker magnet has been performed. The kicker magnet mainly consists of Ni-Zn ferrite cores and Aluminum alloy plates, and these parts are installed in vacuum chamber to prevent discharge because a high voltage is applied to the magnet for a short period. Since it is important to reduce the outgassing of water vapor form these parts to prevent discharge, we has been produced the reserve magnet with low outgassing at high voltage discharge. Since assemble of the kicker magnet already finished and vacuum test has been performed, the result of vacuum test is reported.

MOPME044	A Novel Type of Forward Coupler Slotted Stripline Pickup Electrode for CSRe Stochastic Cooling	impedance, pick-up, vacuum, simulation	571
	J.X. Wu, X.J. Hu, M. Li, J.W. Xia, J.C. Yang, Y. Zhang, G. Zhu IMP, Lanzhou, People's Republic of China F. Caspers CERN, Geneva, Switzerland
	A novel type of slotted or perforated strip-line pick-up or kicker electrode structure for CSRe stochastic cooling for non relativistic particle beams with b=v/c values around 0.7 is presented. This slotted structure is to be used as a forward coupler with the output signal taken from the downstream end and has a rather large relative bandwidth of several octaves. The electrode structure and pickup tank, as well as the beam test result will be presented in this paper.

MOPWA003	New Development of Compact Fast Pulsed Power Supply System in the SPring-8	power-supply, high-voltage, radiation, pulsed-power	666
	C. Mitsuda, K. Fukami, K. Kobayashi, T. Nakanishi, H. Ohkuma, S. Sasaki JASRI/SPring-8, Hyogo-ken, Japan T. Ohshima RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
	We have developed a compact fast pulsed power supply system as a part of the development of the fast kicker magnet system in the SPring-8 storage ring. The kicker magnet is needed for the 1 ps short pulsed X-ray generation by a vertical kick and the suppression of the fast beam oscillation by counter kick. The required pulse width and current for above applications have to be a enough short time less than 4.8 us of the revolution time and more than 200 A respectively. We selected a Si-MOSFET as a switching device because a MOSFET has two capabilities of the fast switching and high-voltage resistance, and has a smaller size than an IGBT. The current are increased by parallel or parallel-series connecting of MOSFETs. We started the development of a test system whose output current was a 67 A with a pulse width of 1.0 us in 2008. From 2009 to 2011, we succeeded in achieving the output current of a 270 A with a pulse width of 0.8 us by using prototype system. In 2012, by increasing the number of MOSFET, we confirmed the output current of 250 A with a pulse width of 0.5 us, whose case size is a just 210(W) x 160(H) x 300(D) mm. We will report the development status in detail.

MOPWA004	Development of a Non-inductive Ceramic Resistor	injection, pulsed-power, impedance, power-supply	669
	T. Sugimoto, K. Fan, K. Ishii, H. Matsumoto KEK, Ibaraki, Japan K. Abe Hitachi Haramachi Electronics Co. Ltd., Hitachishi, Ibaraki, Japan S. Fukuoka University of Tsukuba, Graduate School of Pure and Applied Sciences,, Tsukuba, Ibaraki, Japan
	Non-inductive ceramic resistors, based on alumina and carbon, are used for impedance matching in the circuit of the J-PARC main ring injection kicker system. The kickers were installed in December 2011, and have been in operation successfully since then. However, discharges at the edge of the ceramic bulk were observed after several weeks’ operation, which increase resistance from O(100) to O(1M). Investigation indicates that poor contact with the rough surface of the ceramic bulk due to irregular shaped spots causes micro-gaps, which trigger the discharge. In order to improve the contact, one type of brazing technology has been experimentally applied to one resistor. Another resistor had an annealed thin copper plate inserted, and both resistors were tested and compared. In this paper, we will describe details of the development of the resistors and give future prospects.

MOPWA007	Operating Experience of Kicker Magnet System in the J-PARC 3GeV RCS	high-voltage, synchrotron, extraction, neutron	678
	K. Suganuma, M. Kinsho, T. Togashi, M. Watanabe JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	The J-PARC 3-GeV rapid cycling synchrotron (RCS) has been provided proton beam to the Material and Life Science Facility (MLF)as well as to the 50 GeV Main Ring (MR). Proton beam is accelerated from 181 MeV to 3GeV in the RCS and immediately extracted it to the beam transport line to the MLF and the MR. Extraction kicker system is used for this fast extraction. The RCS has been operated for the neutron and MLF users program from December 23rd, 2008. At the beginning of user operation there were many troubles for the extraction kicker system, especially, thyratron which are used for switch of power supply often caused failure. The beam stop rate due to RCS extraction kicker system was more than 13% in the total beam stop of the J-PARC, establishment and operation experience of the tuning for power supply of the extraction kicker make the beam stop rate less than 0.5% in November 2012. In this paper, we are going to report about daily operation whose main is about operation of thyratron and the maintenance held in summer 2012. And　 We also going to report about the aptitude test of thyratron as a plan of the future.

MOPWA009	Development of a Fast Compensation Kicker System for J-PARC Main-ring Injection	injection, simulation, impedance, power-supply	684
	S. Fukuoka University of Tsukuba, Graduate School of Pure and Applied Sciences,, Tsukuba, Ibaraki, Japan K. Fan, K. Ishii, H. Matsumoto, T. Sugimoto KEK, Ibaraki, Japan
	Injection system of J-PARC main ring employs four lumped kickers to deflect the incoming beam. The residual field caused by tail and reflection of excitation current increases the closed beam orbit leading to particle loss in high power operation. A correction method using a fast kicker system to compensate the remaining angle is being developed. Doe to the narrow bunch spacing, transmission line kicker is selected to satisfy requirements of fast rise and fall time. The kicker magnet uses ceramic capacitors instead of parallel metal plates to make the magnet compact and reduce the stray inductance. Capacitors are installed in vacuum chamber. A very thin core is used to reduce distributed inductance. A bandwidth is calculated as 160 MHz. A Marx generator using FET switches has been studied, which is able to produce fast rise and fall time as 50 ns. Any pulse shape is generated by choosing switches to fire. A prototype magnet and a power supply have been fabricated for parameters test. In this paper, we will report the details of the system design, analyze the measurement results and give future prospects.

MOPWA013	The New Injection System of the HLS II	septum, pulsed-power, controls, storage-ring	687
	L. Shang, Y. Lu, F. Shang, Y.Y. Wang USTC/NSRL, Hefei, Anhui, People's Republic of China
	Funding: The program is funded by NSFC with No. 10875116 and No. 11175181 The 0.8GeV storege ring is being rebuilt in NSRL. The design and construction of the new injection system of the new ring is presented. Kicker magnet, septum magnet and their pulsed power suplies are described. Test results are given. The ceramic chambers, vacuum tank of the septum magnet, system timing and local pulsed power control are also described. The installation and testing of the new system undergoing.

MOPWA026	Fast Magnetic Kickers for the NSLS-II Booster-Synchrotron: Design and Test Results	booster, extraction, injection, vacuum	717
	D.A. Shvedov, O. Anchugov, V.A. Kiselev, A.A. Korepanov, S.V. Sinyatkin BINP SB RAS, Novosibirsk, Russia
	For the purpose of realization of single-turn injection and extraction from the NSLS-II booster synchrotron, BINP members created nanosecond non-vacuum ferrite kickers with fronts of pulsed magnetic field of ~ 200 ns, flat-top duration of 300 nsec and its instability of 0.2/1% at most. This paper describes the design of unique kicker magnets with ceramic vacuum chambers with deposited longitudinal strips of titanium nitride (TiN) inside. The paper also presents the results of bench tests of the kickers: oscillograms of current pulse in bus bars, the shape of the pulsed magnetic field, and transverse distribution of the longitudinal field integral in the kicker aperture.

MOPWA027	Pulse Power Supplies for Kicker Magnets of NSLS-2 Booster Ring	injection, extraction, power-supply, booster	720
	A.A. Korepanov, A. Akimov, A.A. Pachkov, A. Panov BINP SB RAS, Novosibirsk, Russia
	A set of identical ferrite kicker modules is utilized for the injection and extraction of the NSLS-2 booster ring. The pulse power supplies of these modules are based on the PFN-thyratron design. The pulse current amplitude of up to 4 kA at 300 ns flat top duration and PFN charging voltage of up to 23 kV were achieved on the extraction pulsers. The pulse to pulse repeatability of the output current waveform was measured and made up to 0.05% (σ) at nominal current for the extraction pulsers. The injection pulsers have a specification on the reverse current overshoot to be less than 0.5% of the amplitude. To fulfill this requirement a single turn saturated choke in the thyratron circuit was used. The design and the test results of the power supplies on NSLS-2 site are presented in the paper.

MOPWA030	Upgrade of the LHC Injection Kicker Magnets	vacuum, injection, electron, impedance	729
	M.J. Barnes, P. Adraktas, V. Baglin, G. Bregliozzi, S. Calatroni, F. Caspers, H.A. Day, L. Ducimetière, M. Garlaschè, V. Gomes Namora, J.M. Jimenez, N. Magnin, V. Mertens, E. Métral, B. Salvant, M. Taborelli, J.A. Uythoven, W.J.M. Weterings CERN, Geneva, Switzerland
	The two LHC injection kicker systems, comprising 4 magnets per ring, produce a kick of 1.3 T.m with a rise-time of less than 900 ns and a flattop ripple of less than ±0.5%. A beam screen is placed in the aperture of each magnet, to provide a path for the image current of the high intensity LHC beam and screen the ferrite yoke against wake fields. The screen consists of a ceramic tube with conductors in the inner wall. The initially implemented beam screen ensured a low rate of electrical breakdowns while providing an adequate beam coupling impedance. Operation with increasingly higher intensity beams, stable for many hours at a time, now results in substantial heating of the ferrite yoke, sometimes requiring cool down over several hours before the LHC can be refilled. During the long shutdown in 2013/2014 all 8 kicker magnets will be upgraded with an improved beam screen and an increased emissivity of the vacuum tank. In addition equipment adjacent to the injection kickers and various vacuum components will also be modified to help reduce the vacuum pressure in the kickers during high-intensity operation. This paper discusses the upgrades as well as their preparation and planning.

MOPWA031	Beam Induced Ferrite Heating of the LHC Injection Kickers and Proposals for Improved Cooling	vacuum, injection, simulation, impedance	732
	M.J. Barnes, S. Calatroni, F. Caspers, L. Ducimetière, M. Garlaschè, V. Gomes Namora, V. Mertens, Z.K. Sobiech, M. Taborelli, J.A. Uythoven, W.J.M. Weterings CERN, Geneva, Switzerland H.A. Day UMAN, Manchester, United Kingdom
	The two LHC injection kicker systems produce a kick of 1.3 T.m with a flattop duration variable up to 7860 ns, and rise and fall times of less than 900 ns and 3000 ns, respectively. A beam screen is placed in the aperture of each magnet, which consists of a ceramic tube with conductors in the inner wall. The conductors provide a path for the beam image current and screen the ferrite yoke against wake fields. Recent LHC operation, with high intensity beam stable for many hours, resulted in significant heating of both the ferrite yoke and beam impedance reduction ferrites. For one kicker magnet the ferrite yoke approached its Curie temperature. As a result of a long thermal time-constant the ferrites can require several hours to cool enough to re-inject beam, thus limiting the availability of the LHC. Thermal measurement data has been analysed, a thermal model developed and emissivity measurements carried out. The effects of various measures to improve the ferrite cooling have been simulated, including an improved emissivity of the vacuum tank and active cooling on the outside of the tank.

MOPWA032	Reduction of Surface Flashover of the Beam Screen of the LHC Injection Kickers	injection, vacuum, impedance, simulation	735
	M.J. Barnes, P. Adraktas, S. Calatroni, F. Caspers, L. Ducimetière, V. Gomes Namora, V. Mertens, R. Noulibos, M. Taborelli, B. Teissandier, J.A. Uythoven, W.J.M. Weterings CERN, Geneva, Switzerland
	The LHC injection kicker magnets include beam screens to shield the ferrite yokes against wake fields resulting from the high intensity beam. The screening is provided by conductors lodged in the inner wall of a ceramic support tube. Operation with increasingly higher bunch intensity, and narrow bunches, now requires improved ferrite screening. This will be implemented by additional conductors; however the good high-voltage behaviour of the kicker magnets must not be compromised by the supplementary screening. Extensive studies and optimisations have been carried out, to better satisfy the often conflicting requirements for low beam coupling impedance, fast magnetic field rise-time, high vacuum and good high voltage behaviour. A new configuration is proposed which reduces significantly the electric field associated with the screen conductors and the secondary electron yield of the surface of the ceramic tube. Results of high voltage test results are also presented.

MOPWA033	Modelling of Parasitic Inductances of a High Precision Inductive Adder for CLIC	impedance, damping, coupling, emittance	738
	J. Holma, M.J. Barnes CERN, Geneva, Switzerland S.J. Ovaska Aalto University, School of Science and Technology, Aalto, Finland
	The CLIC study is exploring the scheme for an electron-positron collider with high luminosity and a nominal centre-of-mass energy of 3 TeV. The CLIC pre-damping rings and damping rings will produce, through synchrotron radiation, ultra-low emittance beam with high bunch charge. To avoid beam emittance increase, the damping ring kicker systems must provide extremely flat, high-voltage, pulses. The specifications for the extraction kickers of the DRs are particularly demanding: the flat-top of the pulses must be ±12.5 kV with a combined ripple and droop of not more than ±0.02 % (±2.5 V). An inductive adder is a very promising approach to meeting the specifications. However, the output impedance of the inductive adder needs to be well matched to the system impedance. The primary leakage inductance, which cannot be computed accurately analytically, has a significant effect upon the output impedance of the inductive adder. This paper presents predictions, obtained by modelling the 3D geometry of the adder structure and printed circuit boards using the FastHenry code, for primary leakage inductance.

MOPWA042	The Leakage Current Induced by Stray Capacitance in the Pulse Magnet System	impedance, booster, high-voltage, injection	762
	C.S. Chen, C.K. Chan, K.H. Hsu, Y.-H. Liu, C.S. Yang NSRRC, Hsinchu, Taiwan
	A huge amount of current must be provided during the nominal operation of the pulse magnet system in TPS (Taiwan Photon Source). It comes with all kinds of electromagnetic noises, including radiated and conducted EMI (electromagnetic interferences). The primary object of this article is to clarify the paths of induced EMI, especially by means of capacitance induction. Furthermore, some geometrical suggestions which had been tested are listed in this paper as the guidelines of the pulse magnet design. According to the measurement, proper distance and surface area lead to sufficient insulation and reduce the leakage current under the expected value.

MOPWA043	The HV Withstands Test for In Vacuum Booster Kicker	booster, vacuum, injection, extraction	765
	Y.-H. Liu, C.K. Chan, C.S. Chen, H.H. Chen, J.-R. Chen, K.H. Hsu, H.P. Hsueh, Y.T. Huang, C.S. Yang NSRRC, Hsinchu, Taiwan
	The maximum driving voltage of TPS booster extraction kicker is close to 30 kV, the HV insulation should be carefully noticed. A DC withstand voltage tester MUSASHI 3802 (Model: IP-701G) is used to test the DC breakdown voltage, which the maximum driving voltage is 37 kV. The 10 mm gap between coil and ferrite is designed in order to increase HV break down voltage. The safety breakdown distance between HV coil and grounding plate was tested in air. Different insulation material with different thickness was tested the breakdown voltage. Thicker than 10 mm ceramic plate could effectively avoid the breakdown occurred with 37 kV DC charging. Thus HV withstand voltage will be higher in vacuum chamber and the insulation with HV will not be the problem.

MOPWA044	TLS Booster Measurement and Observation by New BPM Electronics	booster, synchrotron, quadrupole, extraction	768
	P.C. Chiu, J. Chen, Y.-S. Cheng, K.T. Hsu, S.Y. Hsu, K.H. Hu, C.H. Kuo NSRRC, Hsinchu, Taiwan
	Taiwan Light Source (TLS) is a 1.5 GeV synchrotron based light source and its booster synchrotron was delivered in 1992. Due to the new project Taiwan Photon Source proceeded at the same site, some up-to-date device are available now before TPS civil construction complete and temporarily adapted for TLS booster to improve its operations. The major parameters of the TLS booster synchrotron are measured. It also provides a chance to experience for the TPS project booster diagnostic.

MOPWA045	The Pulsed Power Supply System for TPS Project	injection, power-supply, booster, storage-ring	771
	C.-S. Fann, C.L. Chen, K.T. Hsu, S.Y. Hsu, A.P. Lee, K.-K. Lin, K.L. Tsai NSRRC, Hsinchu, Taiwan
	The pulsed power supply system for TPS project consists of three types of pulser for booster injection/extraction and storage ring injection. Categorizing by the delivered peak current, pulse shape base-width, they are for: 1) booster kicker: 500 A, square, 1 μs; 2) storage ring kicker: 5 kA, half-sine, 5 μs; 3) transfer line septum: 10 kA, half-sine, 300 μs; respectively. All together, there are 10 units constructed for the associated pulsed magnets. In this report, the test results of the pulsed power supplies will be summarized and the measured results of their performance are presented.

MOPWO022	Design and Manufacturing Description of the Prototype Striplines for the Extraction Kicker of the CLIC Damping Rings	impedance, extraction, damping, vacuum	930
	C. Belver-Aguilar, A. Faus-Golfe IFIC, Valencia, Spain M.J. Barnes CERN, Geneva, Switzerland J. Gómez Trinos Vacuum Projects, Paterna, Spain D. Gutiérrez Arribas Trinos Vacuum Projects, S.L., Paterna - Valencia, Spain F. Toral CIEMAT, Madrid, Spain
	The Pre-Damping Rings (PDRs) and Damping Rings (DRs) of CLIC are needed to reduce the beam emittances to the small values required for the main linacs. The injection and extraction, from the PDRs and DRs, are carried out by kicker systems. In order to achieve both low beam coupling impedance and reasonable broadband impedance matching to the electrical circuit, striplines have been chosen for the kicker elements. The design of the stripline kicker was previously carried out by modelling the striplines with simulation codes such as HFSS, Quickfield and CST Particle Studio. In order to have a complete analysis of the striplines, the effect of electrodes supports and coaxial feedthroughs have been studied in detail. In this paper, electromagnetic analyses of the complete striplines, including fabrication tolerances, are reported. Furthermore, a new idea for impedance matching is presented.

MOPWO025	Optics and Protection of the Injection and Extraction Regions of the CLIC Damping Rings	extraction, injection, damping, septum	939
	R. Apsimon, B. Balhan, M.J. Barnes, J. Borburgh, B. Goddard, Y. Papaphilippou, J.A. Uythoven CERN, Geneva, Switzerland
	The optics design of the injection and extraction regions for the CLIC damping rings is presented. The design defines the parameters for the kicker magnets and septa in these regions and has been optimised to minimise the length of the insertions within the parameter space of the system. Failure modes of the injection and extraction elements are identified and their severity assessed. Protection elements for the injection and extraction regions are optimised based on the conclusions of the failure mode analysis.

MOPWO046	Simulations and Measurements of Beam Losses on LHC Collimators during Beam Abort Failures	simulation, proton, collimation, emittance	996
	L. Lari, C. Bracco, R. Bruce, B. Goddard, S. Redaelli, B. Salvachua, G. Valentino CERN, Geneva, Switzerland A. Faus-Golfe, L. Lari IFIC, Valencia, Spain G. Valentino University of Malta, Information and Communication Technology, Msida, Malta
	Funding: The HiLumi LHC Design Study is included in the HL-LHC project and is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404. One of the main purposes of tracking simulations for collimation studies is to produce loss maps along the LHC ring, in order to identify the level of local beam losses during nominal and abnormal operation scenarios. The SixTrack program is the standard tracking tool used at CERN to perform these studies. Recently, it was expanded in order to evaluate the proton load on different collimators in case of fast beam failures. Simulations are compared with beam measurements at 4 TeV. Combined failures are assumed which provide worst-case scenarios of the load on tungsten tertiary collimators.

MOPWO047	Studies of Thermal Loads on Collimators for HL-LHC Optics in case of Fast Losses	optics, proton, luminosity, collimation	999
	L. Lari, R. Bruce, F. Cerutti CERN, Geneva, Switzerland L. Lari IFIC, Valencia, Spain
	Funding: The HiLumi LHC Design Study is included in the HL-LHC project and is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404. The new layouts for the HL-LHC pose new challenges in terms of proton loads on the collimators around the ring, in particular for the ones of in experimental regions that become critical with squeeze optics. New layouts are under consideration, which foresee updated collimation schemes. Simulations of halo loads for in case of fast failures have been setup with SixTrack in order to determine beam loss distributions for realistic error scenarios. The particle tracking studies might then be interfaced to tools like FLUKA to evaluate the thermal loads on collimators in case of failures. In this paper, the preliminary studies performed for the baseline HL-LHC optics layouts are presented.

MOPWO058	Injection Simulations for TPS Storage Ring	injection, storage-ring, simulation, lattice	1022
	C.C. Chiang, P.J. Chou NSRRC, Hsinchu, Taiwan
	We present injection simulations for the TPS (Taiwan Photon Source) storage ring. The baseline lattice of TPS storage ring is a 6-fold structure with 24 double bend cells. For the Step I commissioning, only baseline lattice with dummy chambers are installed. The three double mini-beta-y lattice with insertion devices will be applied during Step II commissioning. The Tracy-2 program is used to simulate the particle motion in 6-D phase space. We adopt lattice models which include errors of alignments and magnet fields. The particle loss due to scraping by chamber limit is recorded in Tracy-2 simulation. We can estimate the radiation distribution of a ring and provide a reference for the shielding design accordingly.

MOPWO078	A Harmonic Kicker Scheme for the Circulator Cooler Ring in the Medium Energy Electron-ion Collider	electron, ion, collider, FEL	1061
	E.W. Nissen, A. Hutton, A.J. Kimber JLAB, Newport News, Virginia, USA
	Funding: Supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC05-06OR23177 and DE-AC02-06CH11357. The current electron cooler design for the proposed Medium Energy Electron-Ion collider (MEIC) at Jefferson Lab utilizes a circulator ring for reuse of the cooling electron bunch up to 100 times to cool the ion beams. This cooler requires a fast kicker system for injecting and extracting individual bunches in the circulator ring. Such a kicker must work at a high repetition rate, up to 7.5 to 75 MHz depending on the number of turns in the recirculator ring. It also must have a very short rise and fall time (of order of 1 ns) such that it will kick an individual bunch without disturbing the others in the ring. Both requirements are orders of magnitude beyond the present state-of-the-art as well as the goals of other on-going kicker R&D programs such as that for the ILC damping rings. In this paper we report a scheme of creating this fast, high repetition rate kicker by combining RF waveforms at multiple frequencies to create a kicker waveform that will, for example, kick every eleventh bunch while leaving the other ten unperturbed. We also present a possible implementation of this scheme as well as discuss its limitations.

TUOAB102	Project X Injector Experiment: Goals, Plan and Status	rfq, ion, cryomodule, solenoid	1093
	A.V. Shemyakin, S.D. Holmes, D.E. Johnson, M. Kaducak, R.D. Kephart, V.A. Lebedev, C.S. Mishra, S. Nagaitsev, N. Solyak, R.P. Stanek, V.P. Yakovlev Fermilab, Batavia, USA D. Li LBNL, Berkeley, California, USA P.N. Ostroumov ANL, Argonne, USA
	Funding: This work was supported by the U.S. DOE under Contract No.DE-AC02-07CH11359 A multi-MW proton facility, Project X, has been proposed and is currently under development at Fermilab. We are carrying out a program of research and development aimed at integrated systems testing of critical components comprising the front end of the Project X. This program is being undertaken as a key component of the larger Project X R&D program. The successful completion of this program will validate the concept for the Project X front end, thereby minimizing a primary technical risk element within Project X. Integrated systems testing, known as the Project X Injector Experiment (PXIE), will be accomplished with a new test facility under construction at Fermilab and will be completed over the period FY12- 17. PXIE will include an H⁻ ion source, a CW 2.1-MeV RFQ and two superconductive RF (SRF) cryomodules providing up to 25 MeV energy gain at an average beam current of 1 mA (upgradable to 2 mA). Successful systems testing will also demonstrate the viability of novel front end technologies that are expected find applications beyond Project X.
	Slides TUOAB102 [1.615 MB]

TUPFI027	Energy Deposition Studies for Fast Losses during LHC Injection Failures	injection, proton, quadrupole, alignment	1397
	A. Lechner, A. Alnuaimi, C. Bracco, F. Cerutti, A. Christov, L.S. Esposito, N.V. Shetty, V. Vlachoudis CERN, Geneva, Switzerland
	Several instances of injection kicker magnet (MKI) failures have occurred in the first years of LHC operation, leading to misinjections or to accidental kicks of circulating bunches. In a few cases, MKI modules imparted a partial or an increased beam deflection, resulting in grazing bunch impact on beam-intercepting devices and consequently leading to significant secondary showers to downstream accelerator elements. In this study, we investigate different failure occurrences where miskicked bunches were incident on the injection beam stopper (TDI) and on one of the auxiliary injection collimators (TCLIB), respectively. FLUKA shower calculations were performed to quantify the energy deposition in superconducting magnets. Different sections of the LHC insertion regions 2 and 8 were studied, including the separation dipole and the inner triplet downstream of the TDI as well as matching section and dispersion suppressor adjacent to the TCLIB. The obtained results are evaluated in view of quench and damage limits.

TUPFI049	Studies of 10 GeV Decay Ring Design for the International Design Study of the Neutrino Factory	insertion, injection, optics, storage-ring	1457
	D.J. Kelliher, C.R. Prior STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom N. Bliss, N.A. Collomb STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom A. Kurup, J. Pasternak Imperial College of Science and Technology, Department of Physics, London, United Kingdom J. Pasternak STFC/RAL, Chilton, Didcot, Oxon, United Kingdom H. Witte BNL, Upton, Long Island, New York, USA
	Due to the discovery of large θ13 the final muon storage energy in the baseline solution of International Design Study for the Neutrino Factory (IDS-NF) has been set at 10 GeV. A new racetrack design has been produced for the decay ring to meet this requirement. The details of lattice design and the beam dynamics calculations are discussed. The feasibility of the injection system for both positive and negative muons into the ring is explored in details.

TUPME032	Update on Beam Induced RF Heating in the LHC	impedance, injection, proton, simulation	1646
	B. Salvant, O. Aberle, G. Arduini, R.W. Aßmann, V. Baglin, M.J. Barnes, W. Bartmann, P. Baudrenghien, O.E. Berrig, A. Bertarelli, C. Bracco, E. Bravin, G. Bregliozzi, R. Bruce, F. Carra, F. Caspers, G. Cattenoz, S.D. Claudet, H.A. Day, M. Deile, J. Esteban Müller, P. Fassnacht, M. Garlaschè, L. Gentini, B. Goddard, A. Grudiev, B. Henrist, S. Jakobsen, O.R. Jones, O. Kononenko, G. Lanza, L. Lari, T. Mastoridis, V. Mertens, N. Mounet, E. Métral, A.A. Nosych, J.L. Nougaret, S. Persichelli, A.M. Piguiet, S. Redaelli, F. Roncarolo, G. Rumolo, B. Salvachua, M. Sapinski, R. Schmidt, E.N. Shaposhnikova, L.J. Tavian, M.A. Timmins, J.A. Uythoven, A. Vidal, J. Wenninger, D. Wollmann, M. Zerlauth CERN, Geneva, Switzerland H.A. Day UMAN, Manchester, United Kingdom L. Lari IFIC, Valencia, Spain
	Since June 2011, the rapid increase of the luminosity performance of the LHC has come at the expense of increased temperature and pressure readings on specific near-beam LHC equipment. In some cases, this beam induced heating has caused delays whilie equipment cools down, beam dumps and even degradation of these devices. This contribution gathers the observations of beam induced heating attributable to beam coupling impedance, their current level of understanding and possible actions that are planned to be implemented during the long shutdown in 2013-2014.

TUPME033	Evaluation of the Beam Coupling Impedance of New beam Screen Designs for the LHC Injection Kicker Magnets	impedance, coupling, injection, resonance	1649
	H.A. Day UMAN, Manchester, United Kingdom M.J. Barnes, F. Caspers, E. Métral, B. Salvant CERN, Geneva, Switzerland R.M. Jones Cockcroft Institute, Warrington, Cheshire, United Kingdom
	The LHC injection kicker magnets (MKIs) have experienced a significant degree of beam induced heating since the beginning of the 2011 due to the increasing intensity stored in the LHC, for long periods of time, and the relatively large broadband impedance of the installed kicker magnets. In this paper we show the sources of impedance in the MKIs, especially the effect that the beam screen dimensions have on the impedance. We show how these alter the power loss, and present an improved beam screen design that improves shielding on the magnet, whilst further improving electrical breakdown.

TUPME050	Performance Comparison of Different System Identification Algorithms for FACET and ATF2	emittance, simulation, linac, alignment	1679
	J. Pfingstner, A. Latina, D. Schulte CERN, Geneva, Switzerland
	Good system knowledge is an essential ingredient for the operation of modern accelerator facilities. For example, beam-based alignment algorithms and orbit feedbacks rely strongly on a precise measurement of the orbit response matrix. The quality of the measurement of this matrix can be improved over time by statistically combining the effects of small system excitations with the help of system identification algorithms. These small excitations can be applied in a parasitic mode without stopping the accelerator operation (on-line). In this work, different system identification algorithms are used in simulation studies for the response matrix measurement at ATF2. The results for ATF2 are finally compared with the results for FACET, latter originating from an earlier work.

TUPWA009	Bunch by Bunch Intra-Bunch Feedback System for Curing Transverse Beam Instabilities at the J-PARC MR	feedback, impedance, injection, betatron	1739
	O. A. Konstantinova, Y.H. Chin, Y. Kurimoto, T. Obina, M. Okada, K. Takata, M. Tobiyama, T. Toyama KEK, Ibaraki, Japan Y. Shobuda JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	At the J-PARC Main Ring (MR), transverse instabilities have been observed during the injection and at the onset of acceleration with large particle losses. The present bunch by bunch feedback system, operating in a narrowband mode, has been effectively suppressing these instabilities, allowing the beam power to reach 230kW with only 400W of particle losses. The observed beam signals show that bunches are still executing complicated intra-bunch oscillations even if the narrowband feedback system is on, though they are not imposing significant particle losses at present. The new and more advanced broadband feedback system has been developed for control of the intra-bunch oscillations and further reduction of particle losses. The elaborate analysis code has been also developed on the MATLAB platform to analyse effects of the broadband feedback system on intra-bunch oscillations. This paper describes the development of these advanced instruments and presents the analysis of the latest beam test results using the MATLAB code.

TUPWA010	A Trial to Reduce the Kicker Impedance of 3-GeV RCS in J-PARC	impedance, resonance, acceleration, status	1742
	Y. Shobuda, N. Hayashi, T. Takayanagi JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan Y. Irie KEK, Ibaraki, Japan T. Toyama J-PARC, KEK & JAEA, Ibaraki-ken, Japan
	At 3GeV RCS in J-PARC, the kicker impedance has been considered to be the dominant source to cause the beam instability. Recently, experimental studies demonstrate that the beam instability is suppressed by reducing the kicker impedance. In this report, a trial to reduce the kicker impedance is reported.

TUPWA014	The Status of Coupling Impedance Measurement for the CSNS/RCS Extraction Kicker Prototype*	impedance, coupling, simulation, extraction	1754
	L. Huang, Y. Li, R.H. Liu, Y.D. Liu, S. Wang, O. Xiao IHEP, Beijing, People's Republic of China
	Rapid Cycling Synchrotron (RCS) of the China Spallation Neutron Source (CSNS) is a high intensity proton accelerator, with average beam power of 100kW. In order to high intensity beam operation, the beam coupling impedance of the extracted kickers must be controlled. Longitudinal and transverse impedance of extracted kicker prototype with power supply had been roughly measured by coaxial-wire and dual-wire methods respectively. At the same time, impedance of window has been analyzed theoretically and simulated based on CST PARTICLE STUDIO.

TUPWA044	Longitudinal Coupled-Bunch Oscillation Studies in the CERN PS	damping, feedback, cavity, emittance	1808
	H. Damerau, S. Hancock, M.M. Paoluzzi CERN, Geneva, Switzerland M. Migliorati, L. Ventura Rome University La Sapienza, Roma, Italy
	Longitudinal coupled-bunch oscillations are an important limitation for the high-brightness beams accelerated in the CERN PS. Up to the present intensities they are suppressed by a dedicated feedback system limited to the two dominant oscillation modes. In view of the proposed installation of a wide-band feedback kicker cavity within the framework of the LHC Injectors Upgrade project (LIU), measurements have been performed with the existing damping system with the aim of dimensioning the new one. Following the excitation of well-defined oscillation modes, damping times and corresponding longitudinal kick strength are analysed. The paper summarizes the results of the observations and gives an outlook on the expected performance with the new coupled-bunch feedback.

TUPWO004	Preliminary Design of a 4 MW Proton Beam Switchyard for a Neutrino Super Beam Production Facility	target, proton, dipole, quadrupole	1880
	E. Bouquerel, M. Dracos, F.R. Osswald IPHC, Strasbourg Cedex 2, France
	Funding: European Commission Framework Programme 7 Design Study: EUROnu, Project Number 212372. The feasibility of the distribution of 4 MW proton beam power onto a 4-targets horn system for neutrino super-beams production is discussed. A preliminary solution using a pair of bipolar kickers to route the beam onto the targets at a repetition rate of 50 Hz (12.5 Hz per beam line) is proposed. Compensating dipoles would apply symmetry in the system. Magnetic fields induced by these optical elements would not exceed 0.96 T. Studies of the beam envelopes with the code TRANSPORT suggest the use of three quadrupoles per beam line located after the dipoles to focus the 4 mm σ beam onto each target. The length of this switchyard system is estimated to be 29.9 m and 3 m radius.

TUPWO073	Precision Tune, Phase and Beta Function Measurement by Frequency Analysis in RHIC	optics, dipole, betatron, booster	2027
	C. Liu, R.L. Hulsart, A. Marusic, R.J. Michnoff, M.G. Minty, P. Thieberger BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. The high quality of the RHIC turn-by-turn (TbT) data obtained from the beam position monitor (BPM) system was fully exploited by using two analysis approaches. One is a time domain least square fitting technique and the other one is a frequency domain interpolated Fourier Transform technique. Both methods were applied to 1024-turn data from kicked beam and from continuous coherent excitation experiments. The betatron phase precisions obtained with both methods were ~0.1 degree for the continuous excitation and ~0.2 degree for the impulse excitation. The algorithms of these two analyses and comparison of their results will be presented in this report.

WEOBB203	Design of Phase Feed Forward System in CTF3 and Performance of Fast Beam Phase Monitors	optics, quadrupole, pick-up, target	2097
	P. Skowroński, A. Andersson, A. Gerbershagen, E. Ikarios, J. Roberts CERN, Geneva, Switzerland P. Burrows, G.B. Christian, A. Gerbershagen, C. Perry, J. Roberts JAI, Oxford, United Kingdom P. Burrows, G.B. Christian, A. Gerbershagen, C. Perry Oxford University, Physics Department, Oxford, Oxon, United Kingdom A. Ghigo, F. Marcellini INFN/LNF, Frascati (Roma), Italy E. Ikarios National Technical University of Athens, Athens, Greece
	Funding: Work supported by the European Commission under the FP7 Research Infrastructures project Eu- CARD, grant agreement no. 227579 The CLIC two beam acceleration technology requires a drive beam phase stability of better than 0.3 deg rms at 12 GHz, corresponding to a timing stability below 50 fs rms. For this reason the CLIC design includes a phase stabilization feed-forward system. It relies on precise beam phase measurement and its subsequent correction in a chicane with help of fast kickers. A prototype of such a system is being installed in CLIC Test Facility CTF3. In this paper we describe in detail its design and implementation. Additionally, we present and discuss the performance of the precision phase monitor prototypes installed at the end of the CTF3 linac, measured with the drive beam. We would like to acknowledge support of G.Sensolini, A.Zolla (INFN/LNF Frascati), N.S.Chritin and J-M.Scigliuto (CERN) in design and fabrication of components.
	Slides WEOBB203 [6.770 MB]

WEPWA013	Injection Scheme into the High Field ILSF Storage Ring	electron, injection, storage-ring, booster	2156
	H. Ghasem IPM, Tehran, Iran E. Ahmadi, F. Saeidi ILSF, Tehran, Iran
	The injection system into a storage ring of a synchrotron radiation facility significantly affects quality of the electron beam and the radiated x-ray. The extracted 3 GeV electron beam from the booster synchrotron of the ILSF is transferred via the BTS transfer line and injected into the ILSF storage ring based on high field lattice structure. This paper describes the injection procedure into the ILSF storage ring and gives the electron tracking results of the injected beam.

WEPWA051	Extraction Beam Line for Light Sources	extraction, emittance, injection, optics	2232
	M. Aiba, M. Böge, T. Garvey, N. Milas, A. Saá Hernández, A. Streun PSI, Villigen PSI, Switzerland
	Most of measurements, with circulating beam in a ring, to determine transverse and longitudinal phase space volume are rather indirect although it is of importance to characterize these beam parameters for better understanding the machine. Direct measurements may be performed when the beam is extracted to a beam line, where destructive methods are available. However, light sources can tolerate internal beam dumping and thus do not have an extraction line in general. We, therefore, propose a diagnostic dedicated extraction line, motivated by precise determination of the geometrical vertical emittance, which can be a few pm or even less and general comparisons of direct and indirect measurements. Such an extraction beam line has been realized in several accelerator facilities, e.g. KEK-ATF. The idea is, however, to equip a compact beam line, which fits into the existing tunnel and allows us to measure transverse and longitudinal emittances. We present possible design of an extraction beam line assuming typical light source parameters.

WEPWA065	A Non-linear Injection Kicker for Diamond Light Source	injection, emittance, quadrupole, septum	2268
	T. Pulampong, R. Bartolini JAI, Oxford, United Kingdom R. Bartolini Diamond, Oxfordshire, United Kingdom
	Ultra-low emittance lattices will operate with reduced dynamics apertures. New injection schemes are currently investigated in order to guarantee sufficient injection efficiency. A promising candidate is a pulsed kicker with a nonlinear magnetic field. The studies presented in this paper prove that this kicker allows injection with reduced dynamic aperture and provide minimal perturbation of the stored beam during Top-Up injection. Plans to install such a device at the Diamond light source are outlined.

WEPWA070	Design of a Collimation System for the Next Generation Light Source	collimation, gun, undulator, linac	2277
	C. Steier, J.M. Byrd, S. De Santis, P. Emma, D. Li, H. Nishimura, C. F. Papadopoulos, H.J. Qian, F. Sannibale LBNL, Berkeley, California, USA
	Funding: This work is supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. The Next Generation Light Source at LBNL will deliver MHz repetition rate electron beams to an array of free electron lasers. Because of the high beam power approaching one MW in such a facility, effective beam collimation is extremely important to minimize radiation damage, prevent quenches of superconducting cavities, limit dose rates outside of the accelerator tunnel and prevent equipment damage. This paper describes the conceptual design of a collimation system, including detailed simulations to verify its effectiveness.

WEPEA016	Upgrade Study of JPARC Main Ring Fast Extraction Septa System	septum, extraction, injection, acceleration	2531
	K. Fan, K. Ishii, H. Matsumoto, N. Matsumoto, Y. Morita KEK, Ibaraki, Japan
	The JPARC main ring fast extraction (FX) system has two functions, deliver high power beam to the neutrino experimental facility and dump the beam at any time in case of hardware failures. The present FX system consists of five pair of bipolar kickers and eight pair of bipolar septa. In order to raise the beam power to the design limit, both the beam intensity and the repetition rate will increase gradually. The FX system needs to be upgraded to satisfy the new requirements. The upgrade includes FX orbit optimization and new design of devices. Firstly, the conventional multi-turn low-field septa will be replaced by eddy current type septa. Several configurations of the new design has been studied to realize the requirements of thinner septum, higher field quality, lower leakage and higher mechanical stability. To provide sufficient flat top field for the FX beam, superposition of 3rd harmonic pulse has been employed.

WEPEA029	The SHER-HIAF Ring Lattice Design	injection, quadrupole, ion, lattice	2561
	X. Gao, W.P. Chai, G.D. Shen, J. Shi, J.W. Xia, J.C. Yang IMP, Lanzhou, People's Republic of China
	Super Heavy Experimental Ring (SHER) is one of the rings of the next accelerator complex High Intensity Heavy Ion Accelerator Facility (HIAF) at IMP[4]. Here, present ideas of the lattice design for the operation of the large acceptance ring are presented. The SHER ring has to be optimized for e-cooling and the lattice is designed for different modes. First of all, it is designed in the so called isochronous mode as time-of-flight mass spectrometer for short-lived secondary nuclei. Secondly, SHER can also be used to be a storage ring for collecting and cooling the secondary rare isotope beams from the transport line. In order to fulfill it's purpose, the ion optics can be set to different ion optical modes

WEPEA053	Progress with the Upgrade of the SPS for the HL-LHC Era	electron, extraction, simulation, emittance	2624
	B. Goddard, T. Argyropoulos, W. Bartmann, H. Bartosik, T. Bohl, F. Caspers, K. Cornelis, H. Damerau, L.N. Drøsdal, L. Ducimetière, J. Esteban Müller, R. Garoby, M. Gourber-Pace, W. Höfle, G. Iadarola, L.K. Jensen, V. Kain, R. Losito, M. Meddahi, A. Mereghetti, V. Mertens, O. Mete, E. Montesinos, Y. Papaphilippou, G. Rumolo, B. Salvant, E.N. Shaposhnikova, M. Taborelli, H. Timko, F.M. Velotti CERN, Geneva, Switzerland E. Gianfelice-Wendt Fermilab, Batavia, USA
	The demanding beam performance requirements of the HL-LHC project translate into a set of requirements and upgrade paths for the LHC injector complex. In this paper the performance requirements for the SPS and the known limitations are reviewed in the light of the 2012 operational experience. The various SPS upgrades in progress and still under consideration are described, in addition to the machine studies and simulations performed in 2012. The expected machine performance reach is estimated on the basis of the present knowledge, and the remaining decisions that still need to be made concerning upgrade options are detailed.

WEPEA054	CERN PS Optical Properties Measured with Turn-by-turn Orbit Data	resonance, simulation, optics, extraction	2627
	C. Hernalsteens, T. Bach, S.S. Gilardoni, M. Giovannozzi, A. Lachaize, G. Sterbini, R. Tomás, R. Wasef CERN, Geneva, Switzerland
	The performance of the PS has been constantly increasing over the years both in terms of beam parameters (intensity and brightness) and beam manipulations (transverse and longitudinal splitting). This implies a very good knowledge of the linear and non-linear model of the ring. In this paper we report on a detailed campaign of beam measurements based on turn-by-turn orbit data aimed at measuring the optics in several conditions as well as the resonance driving terms. The goal of this study is to assess whether any specific correction system should be envisaged to achieve the required future performance.

WEPEA056	Design and Beam Measurements of Modified Fast Extraction Schemes in the CERN PS for Installing a Dummy Septum to Mitigate Ring Irradiation	extraction, septum, closed-orbit, emittance	2633
	C. Hernalsteens, H. Bartosik, L.N. Drøsdal, S.S. Gilardoni, M. Giovannozzi, A. Lachaize, Y. Papaphilippou, A. Ulsroed CERN, Geneva, Switzerland
	The proposed Multi-Turn Extraction (MTE) for the CERN PS allows to reduce the overall extraction losses for high intensity beams. The required longitudinal structure of the proton beam induces unavoidable beam losses at the magnetic extraction septum. The installation of a dummy septum with an appropriate shielding has been proposed to localise losses and to shadow the magnetic septum. Such a device, located in the extraction region, imposes tight constraints on the available beam aperture. Modified extraction schemes have been proposed and in this paper they will be presented and discussed in detail together with the measured performance.

WEPEA057	Numerical Simulations to Evaluate the Performance of CERN PS Dummy Septum to Reduce Irradiation for the Multi-Turn Extraction	septum, extraction, shielding, beam-losses	2636
	C. Hernalsteens, S. Damjanovic, S.S. Gilardoni, M. Giovannozzi CERN, Geneva, Switzerland
	The losses created by the proposed Multi-Turn Extraction (MTE) at the CERN PS induces high activation of the magnetic extraction septum due to the de-bunched longitudinal beam structure requested to transfer the beam to the SPS. A mitigation measure is under study aiming at localizing losses in a well-shielded area by shadowing the magnetic extraction septum thanks to septum-like passive device. Such a solution is based on a so-called dummy septum, a blade which absorbs particles during the rise time of the extraction kickers for MTE beams. The efficiency of the scheme is presented in this paper. The quantitative estimate is based on detailed simulations that analyse the beam-matter interaction and provide a determination of the shadowing effect of the dummy septum.

WEPEA077	Applying the 'Simple Accelerator Modelling in Matlab' (SAMM) Code to High Luminosity LHC Upgrade	proton, dipole, dynamic-aperture, quadrupole	2690
	K.M. Hock, A. Wolski Cockcroft Institute, Warrington, Cheshire, United Kingdom R. Appleby UMAN, Manchester, United Kingdom
	The "Simple Accelerator Modelling in Matlab" (SAMM) code is a set of Matlab routines for modelling beam dynamics in high energy particle accelerators. It includes a set of CUDA codes that can be run on a Graphics Processor Unit. These can be called from SAMM and can speed up tracking simulations by 100 times. To make use of this potential for the computationally intensive LHC upgrade simulations, we have developed additional Matlab and CUDA routines to simulate the full set of elements that are present in the Large Hadron Collider. We present the results of applying these codes to dynamic aperture calculations. These results are benchmarked against PTC and MADX.

WEPFI006	Broad and Narrow Band Feedback Systems at ELSA	feedback, cavity, HOM, damping	2714
	M. Schedler, F. Frommberger, P. Hänisch, W. Hillert, C. Reinsch ELSA, Bonn, Germany
	At the Electron Stretcher Facility ELSA of Bonn University, an upgrade of the maximum stored beam current from 20 mA to 200 mA is planned. The storage ring operates applying a fast energy ramp of 6 GeV/s from 1.2 GeV to 3.5 GeV. The intended upgrade is mainly limited due to the excitation of multibunch instabilities. As a countermeasure, we succesfully commissioned state-of-the-art bunch by bunch feedback systems in the longitudinal and the two transverse dimensions. In addition, a narrow band cavity based feedback system for damping the most harmful longitudinal multi bunch mode caused by a HOM of the accelerating cavities is under construction.

WEPME003	Determination of Optics Transfer between the Kicker and BPMs for Transverse Feedback System	feedback, betatron, optics, synchrotron	2923
	M. Alhumaidi, A.M. Zoubir TU Darmstadt, Darmstadt, Germany J. Grieser TU Darmstadt, RTR, Darmstadt, Germany
	The knowledge of the transfer optics between the positions of the Kicker and the BPMs is required for the calculation of the correction signal in transverse feedback systems. Therefore, using nominal values of the transfer optics with uncertainties leads to feedback quality degradation, and thus beam disturbances. In this work, we propose a method for measuring the phase advances and amplitude scaling between the positions of the kicker and the BPMs. Directly after applying a kick on the beam by means of the kicker, we record the BPM signals. Consequently, we use the Second-Order Blind Identification (SOBI) algorithm to decompose the noised recorded signals into independent sources mixture. Finally, we determine the required optics parameters by identifying and analyzing the betatron oscillation sourced from the kick based on its mixing and temporal patterns. Results for the heavy ions synchrotron SIS 18 at the GSI are shown.

WEPME011	Beam Tests and Plans for the CERN PS Transverse Damper System	emittance, damping, injection, betatron	2947
	A. Blas, S.S. Gilardoni, G. Sterbini CERN, Geneva, Switzerland
	The CERN Proton Synchrotron (CPS) has been running without any transverse damping equipment since 1998, thanks to the stabilizing effect of the linear coupling applied between horizontal and vertical planes. Lately, the demand for an active damper strongly emerged for two main reasons: to avoid restrictions as imposed on the betatron tune settings by the linear coupling and to cure instabilities appearing with high intensity beams, especially at the extraction energy. Late in 2012, two electronic prototype units, newly developed for the CPS one-turn-feedback, were programmed with a firmware designed to satisfy the transverse feedback (TFB) requirements in both planes. The main achievements were to automatically adapt the loop delay to the particles' time-of-flight variation within a nanosecond precision and to compensate the changing betatron phase advance between pick-up and kicker during the entire accelerating cycle. With the power equipment limited to the modest bandwidth of 23 MHz and 2 x 800 W per plane, encouraging results were obtained such as fast damping of injection oscillations caused by injection errors, reduction of beam losses along the cycle and damping of instabilities at all CPS energies.

WEPME042	Modelling and Studies for a Wideband Feedback System for Mitigation of Transverse Single Bunch Instabilities	feedback, pick-up, injection, electron	3019
	K.S.B. Li, W. Höfle, G. Rumolo CERN, Geneva, Switzerland J.M. Cesaratto, J.E. Dusatko, J.D. Fox, M.T.F. Pivi, K.M. Pollock, C.H. Rivetta, O. Turgut SLAC, Menlo Park, California, USA
	As part of the LHC injector upgrade a wideband feedback system is under study for mitigation of coherent single bunch instabilities. This type of system may provide a generic way of shifting the instability threshold to regions that are currently inaccessible, thus, boosting the brightness of future beams. To study the effectiveness of such systems, a numerical model has been developed that constitutes a realistic feedback system including real transfer functions for pickup and kicker, realistic N-tap FIR and IIR filters as well as noise and saturation effects. Simulations of SPS cases have been performed with HeadTail to evaluate the feedback effectiveness in the presence of electron clouds and TMCI. Some results are presented addressing bandwidth limitations, noise issues and amplifier power requirements.

WEPME043	Performance of the LHC Transverse Damper with Bunch Trains	damping, feedback, injection, pick-up	3022
	W. Höfle, F. Dubouchet, G. Kotzian, D. Valuch CERN, Geneva, Switzerland
	In 2012 the LHC has operated for Physics with bunch trains at 50 ns spacing. Tests have been performed with the nominal design bunch spacing of 25 ns. The transverse damper has been an essential element to provide beam stability for the multi-bunch beam with up to 1380 bunches used at 50 ns spacing. We report on the experience gained with 50 ns spacing and the improvements in the signal processing tested for the future 25 ns operation. The increase in bandwidth required for 25 ns spacing constituted a particular challenge. The response of the system was carefully measured and the results used to digitally pre-distort the drive signal to compensate for a drop in gain of the power system for higher frequencies. The bunch-by-bunch data collected from the feedback signal path provided valuable information during the 2012 Physics run that can be further explored for beam diagnostics purposes and instability analysis in the future. Performance estimates are given for the 7 TeV run planned for 2015, at 25 ns bunch spacing.

WEPME053	Latest Performance Results from the FONT 5 Intra Train Beam Position Feedback System at ATF	feedback, extraction, cavity, linear-collider	3049
	M.R. Davis, D.R. Bett, N. Blaskovic Kraljevic, P. Burrows, G.B. Christian, Y.I. Kim, C. Perry JAI, Oxford, United Kingdom R. Apsimon, B. Constance, A. Gerbershagen CERN, Geneva, Switzerland
	A prototype ultra-fast beam-based feedback system for deployment in single-pass beamlines, such as a future lepton collider (ILC or CLIC) or a free-electron laser, has been fabricated and is being tested in the extraction and final focus lines of the Accelerator Test Facility (ATF) at KEK. FONT5 is an intra-train feedback system for stabilising the beam orbit via different methods: a position and angle feedback correction in the extraction line or a vertical feedforward correction applied at the interaction point (IP) . Two systems comprise three stripline beam position monitors (BPMs) and two stripline kickers in the extraction line, two cavity BPMs and a stripline kicker at the IP, a custom FPGA-based digital processing board, custom kicker-drive amplifiers and low-latency analogue front-end BPM processors. Latest results from the experiment are presented. These include beam position correction in the extraction line, as well as preliminary results of beam correction at the IP.

WEPME059	A 4 GS/sec Instability Feedback Processing System for Intra-bunch Instabilities	feedback, controls, pick-up, injection	3067
	J.E. Dusatko, J.M. Cesaratto, J.D. Fox, J.J. Olsen, K.M. Pollock, C.H. Rivetta, O. Turgut SLAC, Menlo Park, California, USA W. Höfle CERN, Geneva, Switzerland
	Funding: Work supported by the U.S. Department of Energy under contract DE-AC02-76SF00515 and the US LHC Accelerator Research program ( LARP) We present the architecture and implementation overview of a proof-of-principle digital signal processing system developed to study control of Electron-Cloud and Transverse Mode Coupling Instabilities (TMCI) in the CERN SPS. This system is motivated by intensity increases planned as part of the High Luminosity LHC upgrade. It is based on a reconfigurable processing architecture which samples intra-bunch motion and applies correction signals at a 4GSa/s rate, allowing multiple samples across a single 2ns SPS bunch. This initial demonstration system is a rapidly developed prototype consisting of both commercial and custom-designed hardware that implements feedback control on a single bunch. It contains a high speed ADC and DAC, capable of sampling at up to 4GSa/s, with a 16-tap FIR control filter for each bunch sample slice. Other system features include a timing subsystem to synchronize the sampling to the injection and the bunch 1 markers, the capability of generating arbitrary time domain signals to drive the bunch and diagnostic functions including a snapshot memory for ADC data. This paper describes the design, construction and operational experience of this system.

WEPME060	First Results and Analysis of the Performance of a 4 GS/s Intra-bunch Vertical Feedback System at the SPS	feedback, controls, injection, damping	3070
	J.M. Cesaratto, J.E. Dusatko, J.D. Fox, J.J. Olsen, K.M. Pollock, C.H. Rivetta, O. Turgut SLAC, Menlo Park, California, USA H. Bartosik, W. Höfle, G. Kotzian, U. Wehrle CERN, Geneva, Switzerland
	Funding: Work supported by the U.S. Department of Energy under contract DE-AC02-76SF00515 and the US LHC Accelerator Research program ( LARP) We present experimental measurements taken from SPS machine development studies with an intra-bunch feedback channel. These studies use a digital signal processing system to implement general-purpose control algorithms on multiple samples across a single SPS bunch ( for ease of synchronization with the SPS RF frequency a sampling frequency of 3.2 GS/sec. is implemented). These initial studies concentrate on single-bunch motion, and study the vertical betatron motion as the feedback control is varied. The studies are focused on validating simulation models of the beam dynamics with feedback. Time and frequency domain results include excitation and damping of intra-bunch motion with positive and negative feedback. We present an overview of the challenges of intra-bunch feedback, and highlight methods to time-align the pickup and kicker signals within the closed-loop feedback channel.

WEPME061	A Wideband Slotted Kicker Design for SPS Transverse Intra-bunch Feedback	impedance, feedback, coupling, simulation	3073
	J.M. Cesaratto, J.D. Fox, C.H. Rivetta SLAC, Menlo Park, California, USA D. Alesini, A. Drago, A. Gallo, F. Marcellini, M. Zobov INFN/LNF, Frascati (Roma), Italy S. De Santis LBNL, Berkeley, California, USA W. Höfle CERN, Geneva, Switzerland
	Funding: Work supported by the U.S. Department of Energy under contract DE-AC02-76SF00515 and the US LHC Accelerator Research Program (LARP) and by the EU FP7 HiLumi LHC - Grant Agreement 284404. Control and mitigation of transverse beam instabilities caused by electron cloud and TMCI will be essential for the SPS to meet the beam intensity demands for the HL-LHC upgrade. A wideband intra-bunch feedback method is in development, based on a 4 GS/s data acquisition and processing, and with a back end frequency structure extending to 1 GHz. A slotted type kicker, similar to those used for stochastic cooling, has been considered as the terminal element of the feedback chain. It offers the most promising deflecting structure characteristics to meet the system requirements in terms of bandwidth, shunt impedance, and beam coupling impedance. Different types of slotted structures have been explored and simulated, including a ridged waveguide and coaxial type waveguide. In this paper we present our findings and the conceptual design of a vertical SPS wideband kicker consistent with the stay clear, vacuum, frequency band coverage, and peak shunt impedance requirements.

THOBB102	Beam Coupling Impedance Localization Technique Validation and Measurements in the CERN Machines	impedance, quadrupole, lattice, betatron	3106
	N. Biancacci, G. Arduini, T. Argyropoulos, H. Bartosik, R. Calaga, K. Cornelis, S.S. Gilardoni, N. Mounet, E. Métral, Y. Papaphilippou, S. Persichelli, G. Rumolo, B. Salvant, G. Sterbini, R. Tomás, R. Wasef CERN, Geneva, Switzerland M. Migliorati, L. Palumbo URLS, Rome, Italy
	The beam coupling impedance could lead to limitations in beam brightness and quality, and therefore it needs accurate quantification and continuous monitoring in order to detect and mitigate high impedance sources. In the CERN machines, for example, kickers and collimators are expected to be the main contributors to the total imaginary part of the transverse impedance. In order to detect the other sources, a beam based measurement was developed: from the variation of betatron phase beating with intensity, it is possible to detect the locations of main impedance sources. In this work we present the application of the method with beam measurements in the CERN PS, SPS and LHC.
	Slides THOBB102 [7.224 MB]

THPEA041	Performance Improvements of the SPS Internal Beam Dump for the HL-LHC Beam	vacuum, proton, dumping, synchrotron	3231
	F.M. Velotti, O. Aberle, C. Bracco, E. Carlier, P. Chiggiato, J.A. Ferreira Somoza, B. Goddard, M. Meddahi, V. Senaj, J.A. Uythoven CERN, Geneva, Switzerland
	The SPS internal beam dump has been designed for beam specifications well below the HL-LHC ones, and for modes of operation which may not be adequate for the HL-LHC era. The present system suffers from several limitations in the allowed intensity and energy range, and its vacuum performance affects nearby high-voltage kicker systems. In this report the limitations of the internal beam dump system are reviewed, and the possible improvements compared. Preliminary upgrade proposals are presented, taking into consideration the expected operational HL-LHC parameters.

THPEA045	Beam Induced Quenches of LHC Magnets	injection, quadrupole, beam-losses, simulation	3243
	M. Sapinski, T. Baer, M. Bednarek, G. Bellodi, C. Bracco, R. Bruce, B. Dehning, W. Höfle, A. Lechner, E. Nebot Del Busto, A. Priebe, S. Redaelli, B. Salvachua, R. Schmidt, D. Valuch, A.P. Verweij, J. Wenninger, D. Wollmann, M. Zerlauth CERN, Geneva, Switzerland
	In the years 2009-2013 LHC was operating with the beam energy of 3.5 and 4 TeV instead of the nominal 7 TeV, with the corresponding currents in the superconducting magnets also half nominal. To date only a small number of beam-induced quenches have occurred, with most being due to specially designed quench tests. During normal collider operation with stored beam there has not been a single beam induced quench. This excellent result is mainly explained by the fact that the cleaning of the beam halo worked very well and, in case of beam losses, the beam was dumped before any significant energy was deposited in the magnets. However, conditions are expected to become much tougher after the long LHC shutdown, when the magnets will be working at near nominal currents in the presence of high energy and intensity beams. This paper summarizes the experience to date with beam-induced quenches. It describes the techniques used to generate controlled quench conditions which were used to study the limitations. Results are discussed along with their implication for LHC operation after the first Long Shutdown.

THPEA052	TLS Operation Information Management: Automatic Logging Tools	booster, injection, klystron, linac	3261
	C.C. Liang, H.C. Chen, J. Chen, C.K. Chou, S. Fann, K.T. Hsu, K.H. Hu, J.A. Li, D. Lin, T.F. Lin, Y.K. Lin, Y.-C. Liu, C.Y. Wu NSRRC, Hsinchu, Taiwan Y.-C. Liu NTHU, Hsinchu, Taiwan
	The Taiwan Light Source (TLS) has been operated in the Top-up mode since October 2005 and has maintained a beam current of 360mA since 2010. Several essential parameters and waveforms are constantly recorded as routine accelerator operation reference. Therefore, five LabVIEW-based data and waveform logging software programs have been developed for the purpose of preliminary diagnose at the TLS. In this report, certain actual cases in regular operation are presented.

THPFI015	In-situ Degassing of the Ferrite Cores in the Extraction Kicker Magnets of the J-PARC 3-GeV RCS	vacuum, target, shielding, quadrupole	3324
	J. Kamiya, Y. Hikichi, M. Kinsho, M. Nishikawa, N. Ogiwara, K. Suganuma, T. Yanagibashi JAEA/J-PARC, Tokai-mura, Japan
	Kicker magnets extract the accelerated beam to the beam transport lines in the RCS of the J-PARC. The kicker magnets mainly consist of Ni-Zn ferrite cores and Al alloy plates, and are installed in a vacuum to prevent discharge because a high voltage is applied for a short period. It is important to reduce the outgassing of water vapor from the ferrite cores. Although the kicker magnets have been working well, recently the vacuum quality became a little poor. Thus, we developed the in-situ degassing method for the ferrite cores. This is achieved by directing the heat from the heat source to the kicker magnet and not to the chamber wall. With the test stand we succeeded to flow almost all the heat toward the kicker magnet and to bake out the ferrite cores about 150°C, maintaining the temperature of the chamber wall less than 50°C. As the previous work with TDS measurements revealed that the absorbed water molecules can be easily removed by the bake-out at 100-150°C in a vacuum, the outgassing from the ferrite cores was successfully reduced. The details of the in-situ degassing method will be reported, including the practical method to reduce the outgassing of the working kickers.

THPWO073	European Spallation Source Afterburner Concept	neutron, proton, target, linac	3924
	D.P. McGinnis, M. Lindroos, R. Miyamoto ESS, Lund, Sweden
	The European Spallation Source (ESS) is a long pulsed source based on a high power superconducting linac. The long pulse concept is an excellent strategy of maximizing high beam power while minimizing peak power on the target. Chopping in the long pulse concept provides the necessary resolution for many neutron physics applications. However, there are some neutron physics applications in which both peak neutron flux and high resolution are desired. The peak flux of the ESS can be enhanced by placing an accumulator ring at the end of the linac. A bunch by bunch extraction scheme can be used to optimize the proton pulse time profile that maximizes peak neutron flux while minimizing instantaneous beam power on the target.

FRXCA01	Progress in Transverse Feedbacks and Related Diagnostics for Hadron Machines	feedback, injection, hadron, damping	3990
	W. Höfle CERN, Geneva, Switzerland
	Today Hadron Accelerators with high intensity and high brightness beams increasingly rely on transverse feedback systems for the control of instabilities and the preservation of the transverse emittance. With particular emphasis, but not limited, to the CERN Hadron Accelerator Chain the progress made in recent years and the performances achieved are reviewed. Hadron colliders such as the LHC represent a particular challenge as they ask for low noise electronic systems in these feedbacks for acceptable emittance growth. Achievements of the LHC transverse feedback system used for damping injection oscillations and to provide stability throughout the cycle are summarized. This includes its use for abort gap and injection cleaning as well as transverse blow-up for diagnostics purposes. Beyond systems already in operation, advances in technology and modern digital signal processing with increasingly higher digitization rates have made systems conceivable to cure intra-bunch motion. With its capabilities to both acquire beam oscillations and to actively excite motion, transverse feedback systems have a large variety of applications for beam diagnostics purposes.
	Slides FRXCA01 [4.985 MB]

Paper

Title

Other Keywords

Page

MOPEA013

Radioactive Beam Accumulation for a Storage Ring Experiment with an Internal Target

target, electron, ion, injection

91

F. Nolden, C. Dimopoulou, R. Grisenti, C.M. Kleffner, S.A. Litvinov, W. Maier, C. Peschke, P. Petri, U. Popp, M. Steck, H. Weick, D.F.A. Winters, T. Ziglasch
GSI, Darmstadt, Germany

A radioactive ⁵⁶Ni beam was successfully accumulated for an experiment with an internal hydrogen target at the storage ring ESR of GSI, Germany. The radioactive beam was produced and separated at the GSI fragment separator from a stable ⁵⁸Ni beam. About 6·10⁴ ⁵⁶Ni ions were injected into the ESR on a high relative momentum orbit. The beam was subjected to stochastic cooling, bunched and transported to a low relative momentum orbit where it was neither disturbed by the field of the partial aperture injection kicker nor by the fields of the stochastic cooling kickers. Slightly below this deposition momentum, the beam was accumulated and continuously cooled by means of electron cooling. For each experiment with internal hydrogen target, about 80 shots were injected consecutively, leading to a stored beam of roughly 5·10⁶ particles.

MOPEA016

The Main Stochastic Cooling System of the HESR

pick-up, accumulation, vacuum, simulation

100

R. Stassen, R. Greven, R. Maier, G. Schug, H. Stockhorst
FZJ, Jülich, Germany

The main stochastic cooling system of the High-Energy Storage Ring HESR (1.5-15 GeV/c) for antiprotons at the FAIR complex (Facility for Antiprotons and Ion Research) in Darmstadt (GSI) will work in the frequency range of 2 - 4 GHz. The design work on pickup and kicker is now finished and the production of the first cooling tank has been started. The whole system layout will be presented taking into account new additional requirements concerning the accumulation and the cooling of heavy ions. All beam-coupling structures are nearly identical and contain several ring-slot blocks. These blocks consist of eight wall-current monitors coupled out by eight electrodes each. Most of the signal combining and splitting take place within the vacuum envelope to reduce the number of vacuum RF feed throughs. The long-distance transmission of the signals and the filters containing long signal delays work with near infrared optical elements.

MOPEA043

Transverse Instabilities of Two Twisted Beams in a Storage Ring

ion, electron, storage-ring, simulation

172

B.C. Jiang, M.Z. Zhang, Z.T. Zhao
SINAP, Shanghai, People's Republic of China
G.X. Xia
UMAN, Manchester, United Kingdom

Two twisted beams (two beams run on the different closed orbit) in a storage ring which is produced by fast kickers can potentially deliver two bunds of radiations through one insertion device or one bend magnet, in this way doubles the beam line stations. This operation mode needs higher beam current and more RF buckets to be filled to keep the brightness comparable to the single beam operation mode. The resistive wall instability and ion trapping effects is analysed to address the higher current operation possibility. The analyze results show that twisted beams can weaken those two instabilities.

MOPEA055

First Year Operation of the ALBA Synchrotron Light Source

vacuum, storage-ring, interlocks, feedback

202

F. Pérez
CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain

ALBA is a 3 GeV, 3rd generation, light source located in Cerdanyola, Barcelona, Spain, which started users operation in May 2012. In this paper we will report about the transition from commissioning to operation, the main problems faced during this first year, the actual status of the accelerators and we will provide an outlook to the next steps.

MOPEA059

The Optimization of Transverse Stripline Kicker

simulation, vacuum, impedance, insertion

214

H.P. Hsueh, C.-C. Chang, Y.P. Chang, J.-R. Chen, Y.T. Cheng, G.-Y. Hsiung, Y.C. Yang
NSRRC, Hsinchu, Taiwan
J.-R. Chen
National Tsing Hua University, Hsinchu, Taiwan

The construction of a new 3 GeV synchrotron facility, Taiwan Photon Source, is ongoing. It is required to install stripline kickers to suppress instability generated by mismatch between injection kickers or imperfect installation of vacuum components all around. First, the design philosophy will be described for transverse stripline kickers. HFSS electromagnetic simulation software is used to optimize all structure parameters like electrode dimensions, electrode distance from vacuum chambers etc. to make transverse stripline kicker working more efficiently and effectively. All simulation results will be presented in this paper and all structure dimension choices will be discussed and the final prototype structure dimensions will be selected from the discussion.

MOPEA061

Operation Experience at Taiwan Light Source

SRF, cavity, diagnostics, injection

220

Y.-C. Liu, H.H. Chen, H.C. Chen, S. Fann, S.J. Huang, J.A. Li, C.C. Liang, Y.K. Lin, Y.-H. Lin, M.-S. Yeh
NSRRC, Hsinchu, Taiwan

A matrix structure has been implemented for the purpose of successful operation of TLS and continuous progress of Taiwan Photon Source (TPS) construction. A dedicated and flexible manpower distribution has proven it could keep as same performance of TLS operation as possible. We will summarize the machine operation experience at TLS during TPS civil construction period.

MOPEA080

Status of the NSLS-II Injector

booster, linac, injection, storage-ring

273

T.V. Shaftan, A. Blednykh, E.B. Blum, W.X. Cheng, J. Choi, L.R. Dalesio, M.A. Davidsaver, J.H. De Long, R.P. Fliller, G. Ganetis, F. Gao, A. Goel, W. Guo, K. Ha, R. Heese, H.-C. Hseuh, M.P. Johanson, B.N. Kosciuk, S. Kowalski, S.L. Kramer, Y. Li, W. Louie, S. Ozaki, D. Padrazo, J. Rose, S. Seletskiy, S.K. Sharma, G. Shen, O. Singh, V.V. Smaluk, Y. Tian, K. Vetter, W.H. Wahl, G.M. Wang, F.J. Willeke, X. Yang, L.-H. Yu, P. Zuhoski
BNL, Upton, Long Island, New York, USA

We discuss the current status and plans for developing the NSLS-II injector. The latter consists of a 200 MeV linac, a 3-GeV booster, transport lines and the storage ring injection straight section. The system design and installation are complete. Last year we concluded 200-MeV linac commissioning and are planning to commission the 3 GeV booster during summer of 2013.

MOPFI030

Study of the Beam Injection and Extraction of the Proton Irradiation Accelerator

injection, proton, extraction, synchrotron

348

Y.W. An, H.F. Ji, S. Wang
IHEP, Beijing, People's Republic of China

The proton irradiation accelerator is widely founded for industry application, and the extracted beam is required to have large intensity as a pulse beam or uniform distribution for scanning. A multi-turn injection is adopted and the proton beam is injected into the ring with the energy of 10MeV. In order to increase injection beam intensity, local bump orbit including two-bump, three-bump and four-bump is well studied and optimized, and the septum magnet thickness and localization are also studied for an effective injection. A RF knock-out method is used for slow extraction due to the fast response character. In order to decrease the global spill, double RF kicker and the control of the aptitude modulation (AM) function of the transverse RF field are well studied.

MOPFI046

Transverse RF Kicker Excitation and Longitudinal RF Noise Diffusion for Slow Extraction from SAPT

extraction, simulation, synchrotron, resonance

386

L. Ouyang, M. Gu, D.M. Li, Q. Yuan, M.Z. Zhang
SINAP, Shanghai, People's Republic of China

Two key techniques used in the slow extraction from synchrotron accelerator: longitudinal RF stochastic noise acceleration, and transverse RF knock out excitation have been studied in this paper. Detailed comparison have revealed the potentials and limits of both methods. For the longitudinal RF stochastic acceleration excitation, the focus has been the phase space compression of particles, which makes the them to hasten around the RF bucket of the cavity, thus to lower the senstivity to ripple. For the transverse RF knock out excitation, the emphasis have been optimal schemes of amplitude modulation and frequency modulation of the RF singals. The optimizations are also used to lower the senstivity of the beam to the ripple and to enhance the uniformity of the extracted beam.

MOPFI050

Non-local Fast Extraction from the CERN SPS at 100 and 440 GeV

extraction, simulation, septum, injection

392

F.M. Velotti, A. Alekou, W. Bartmann, E. Carlier, K. Cornelis, I. Efthymiopoulos, B. Goddard, L.K. Jensen, V. Kain, M. Kowalska, V. Mertens, R. Steerenberg
CERN, Geneva, Switzerland

The Long Straight Section 2 (LSS2) of the CERN SPS is connected with the North Area (NA), to which the beam to date has always been extracted using a resonant extraction technique. For new proposed short- and long-baseline neutrino experiments, a fast single turn extraction to this experimental area is required. As there are no kickers in LSS2, and the integration of any new kickers with the existing electrostatic septum would be problematic, a solution has been developed to fast extract the beam using non-local extraction with other SPS kickers. Two different kicker systems have been used, the injection kicker in LSS1 and the stronger extraction kicker in LSS6 to extract 100 and 440 GeV beam, respectively. For both solutions a large emittance beam was extracted after 5 or 9 full betatron periods. The concept and simulation details are presented with the analysis of the aperture and beam loss considerations and experimental results collected during a series of beam tests.

MOPFI051

Beam Transfer Systems for the LAGUNA-LBNO Long Baseline Neutrino Beam from the CERN SPS

extraction, injection, target, septum

395

B. Goddard, W. Bartmann, I. Efthymiopoulos, Y. Papaphilippou, A.S. Parfenova
CERN, Geneva, Switzerland

For the Long Baseline neutrino facility under study at CERN (LAGUNA-LBNO) it is initially planned to extract a 400 GeV beam from the second long straight section in the SPS into the existing transfer channel TT20 leading to the North Area experimental zone, to a new target aligned with a far detector in Finland. In a second phase a new High-Power Proton Synchrotron (HPPS) accelerator is proposed, to give a 2 MW beam at about 50 GeV on the same target. In this paper the beam transfer systems required for the project are outlined, including the new sections of transfer line between the SPL, HPPS and SPS, and from the SPS to the target, and also the injection and extraction systems in the long straight section of the HPPS. The feasibility of a 4 GeV H⁻ injection system is discussed.

MOPFI052

A New Lead Ion Injection System for the CERN SPS with 50 ns Rise Time

injection, ion, septum, impedance

398

B. Goddard, O. Aberle, J. Borburgh, E. Carlier, K. Cornelis, L. Ducimetière, L.K. Jensen, T. Kramer, D. Manglunki, A. Mereghetti, V. Mertens, D. Nisbet, B. Salvant, L. Sermeus
CERN, Geneva, Switzerland

The LHC High Luminosity upgrade project includes a performance upgrade for heavy ions. One of the present performance limitations is the rise time of the SPS injection kicker system, which imposes a spacing of at least 220 ns between injected bunch trains at the operational rigidity. A reduction of this rise time to 50 ns for lead ions is requested as part of the suite of measures needed to increase the present design performance by a factor three. A new injection system based on a fast pulsed septum and a fast kicker has been proposed to fulfil this rise time requirement, and to meet all the constraints associated with the existing high intensity proton injection in the same region. This paper describes the concept and the required equipment parameters, and explores the implications of such a system for SPS operation.

MOPFI053

Upgrades of the SPS, Transfer Line and LHC Injection Protection Devices for the HL-LHC Era

injection, vacuum, coupling, extraction

401

Ö. Mete, O. Aberle, F. Cerutti, K. Cornelis, B. Goddard, V. Kain, R. Losito, F.L. Maciariello, M. Meddahi, A. Mereghetti, J.A. Uythoven, F.M. Velotti
CERN, Geneva, Switzerland
E. Gianfelice-Wendt
Fermilab, Batavia, USA

The challenging High Luminosity LHC (HL-LHC) beam requirements will lead in the future to unprecedented beam parameters along the LHC injector chain. In the SPS accelerator these requests translate into about a factor two higher intensity and brightness than the present design performance. In addition to the challenge of producing and accelerating such beams, these parameters affect the resistance of the existing equipment against beam impact. Most of the protection devices in the SPS ring, its transfer lines and the LHC injection areas will be put under operational constraints which are beyond their design specification. The equipment concerned has been reviewed and their resistance to the HL-LHC beams checked. Theoretical and simulation studies have been performed for the SPS beam scraping system, the protection devices and the dump absorbers of the SPS-to-LHC transfer lines, as well as for the LHC injection protection devices. The first results of these studies are reported, together with the future prospects.

MOPFI054

Upgrades for the CERN PSB-TO-PS Transfer at 2 GeV

injection, optics, emittance, quadrupole

404

W. Bartmann, J. Borburgh, J.R.T. Cole, S.S. Gilardoni, B. Goddard, O. Hans, M. Hourican, L. Sermeus, R. Steerenberg
CERN, Geneva, Switzerland
C.H. Yu
IHEP, Beijing, People's Republic of China

The CERN PS Booster extraction energy will be upgraded from 1.4 to 2.0 GeV to alleviate the direct space charge tune shift in the PS. The focussing structure of the transfer line will be modified in order to better match the optics between the PSB and the PS. The optics of the PS at injection and, with it, of the transfer line can be adapted to reduce the continuous losses from the already injected and circulating beam bumped towards the septum. Experimental results of the optics optimisation and probing the injection kicker gap will be shown.

MOPFI057

Studies for the LHeC Beam Transfer Systems

linac, injection, electron, extraction

410

C. Bracco, B. Goddard
CERN, Geneva, Switzerland

The LHeC would allow for collisions between an electron beam from a new accelerator with the existing LHC hadron beam. Two possible configurations were studied: a separate LINAC (LINAC-ring) or a new electron ring superimposed on the LHC (ring-ring). The racetrack LINAC is now considered as the baseline for the LHeC design, with the ring-ring solution a back up. The studies performed for all the considered options are presented in this paper. For the LINAC-ring option the requirements for the post-collision line and the beam dump design have been evaluated in the cases of a 140 GeV and a 60 GeV electron beam. In the ring-ring option studies have been performed of the optics design of the transfer line from the a 10 GeV injector LINAC into the LHeC ring and of the injection system. The internal 60 GeV electron ring dump design has also been considered.

MOPFI061

Concept for Elena Extraction and Beam Transfer Elements

extraction, septum, quadrupole, vacuum

422

J. Borburgh, B. Balhan, W. Bartmann, T. Fowler, L. Sermeus, G. Vanbavinckhove
CERN, Geneva, Switzerland
R.A. Baartman
TRIUMF, Vancouver, Canada
D. Barna
University of Tokyo, Tokyo, Japan
V. Pricop
Transilvania University of Brasov, Brasov, Romania

In 2011 the ELENA decelerator was approved as a CERN project. Initially one extraction was foreseen, which should use a kicker and a magnetic septum which can be recuperated from an earlier installation. Since then a second extraction has been approved and a new solution was studied using only electric fields to extract the beam. This will be achieved by fast pulsing a separator, allowing single-bunch but also a full single-turn extraction from ELENA towards the experiments. The extraction and transfer requirements of ELENA are described, followed by the principal differences between the magnetic and electric field concepts. The design of electrostatic focussing and bending devices for the transfer lines will be presented. Finally the field quality which can be achieved with the separator and the concept of its power supply will be discussed.

MOPME008

Beam Diagnostics by Using Bunch-by-bunch Feedback Systems at the DELTA Storage Ring

feedback, injection, laser, electron

485

M. Höner, H. Huck, M. Huck, S. Khan, R. Molo, A. Schick, P. Ungelenk
DELTA, Dortmund, Germany

Funding: Work supported by BMBF (05K10PEB)
At DELTA, a 1.5-GeV electron storage ring operated by the TU Dortmund University, longitudinal and transverse bunch-by-bunch feedback systems are in use to detect and suppress multi-bunch instabilities. Besides that, the digital feedback systems are excellent diagnostics tools. As an example, by exciting a certain number of bunches within the bunch train, the coupling to the non-excited bunches can be investigated below and above the instability threshold. Other examples include studies of the injection process and monitoring bunch oscillations during sudden beam loss. First experimental results will be presented in this paper.

MOPME018

BEAM OSCILLATION MONITOR FOR THE MULTI-BUNCH BEAM

damping, linac, wakefield, extraction

506

T. Naito, S. Araki, H. Hayano, K. Kubo, S. Kuroda, T. Okugi, N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan

In order to observe the motion of bunch-by-bunch beam oscillation of multi-bunch in the storage ring, we developed two measurement tools. One is a signal process electronics circuit using fast analogue switches. The circuit picks up one of the selected bunch signal of the beam position monitor from the multi-bunch. The selected beam position signal can be processed as a single bunch beam. By changing the gate timing, arbitrary bunch signal can be selected. The other is a waveform memory using a high bandwidth oscilloscope. The long waveform memory of the oscilloscope has a capability to acquire the multi-turn waveform of the button electrode signals. The beam test of the circuit has been carried out at KEK-ATF damping ring in the cases of 2.8ns bunch spacing and 5.6ns bunch spacing, respectively. The detail of the hardware and the result of the beam test are reported.

MOPME025

Production of Extraction Kicker Magnet of the J-PARC 3-GeV RCS

vacuum, high-voltage, extraction, proton

526

M. Kinsho, N. Ogiwara, K. Suganuma
JAEA/J-PARC, Tokai-mura, Japan

The J-PARC 3-GeV rapid cycling synchrotron (RCS) has been provided proton beam to the Material and Life Science Facility (MLF)as well as to the 50 GeV Main Ring (MR). Proton beam is accelerated from 181 MeV to 3GeV in the RCS and immediately extracted it to the beam transport line to the MLF and the MR. Extraction kicker magnets are used for this fast extraction. To improve reliability of the RCS for user operation, production of a reserve kicker magnet has been performed. The kicker magnet mainly consists of Ni-Zn ferrite cores and Aluminum alloy plates, and these parts are installed in vacuum chamber to prevent discharge because a high voltage is applied to the magnet for a short period. Since it is important to reduce the outgassing of water vapor form these parts to prevent discharge, we has been produced the reserve magnet with low outgassing at high voltage discharge. Since assemble of the kicker magnet already finished and vacuum test has been performed, the result of vacuum test is reported.

MOPME044

A Novel Type of Forward Coupler Slotted Stripline Pickup Electrode for CSRe Stochastic Cooling

impedance, pick-up, vacuum, simulation

571

J.X. Wu, X.J. Hu, M. Li, J.W. Xia, J.C. Yang, Y. Zhang, G. Zhu
IMP, Lanzhou, People's Republic of China
F. Caspers
CERN, Geneva, Switzerland

A novel type of slotted or perforated strip-line pick-up or kicker electrode structure for CSRe stochastic cooling for non relativistic particle beams with b=v/c values around 0.7 is presented. This slotted structure is to be used as a forward coupler with the output signal taken from the downstream end and has a rather large relative bandwidth of several octaves. The electrode structure and pickup tank, as well as the beam test result will be presented in this paper.

MOPWA003

New Development of Compact Fast Pulsed Power Supply System in the SPring-8

power-supply, high-voltage, radiation, pulsed-power

666

C. Mitsuda, K. Fukami, K. Kobayashi, T. Nakanishi, H. Ohkuma, S. Sasaki
JASRI/SPring-8, Hyogo-ken, Japan
T. Ohshima
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan

We have developed a compact fast pulsed power supply system as a part of the development of the fast kicker magnet system in the SPring-8 storage ring. The kicker magnet is needed for the 1 ps short pulsed X-ray generation by a vertical kick and the suppression of the fast beam oscillation by counter kick. The required pulse width and current for above applications have to be a enough short time less than 4.8 us of the revolution time and more than 200 A respectively. We selected a Si-MOSFET as a switching device because a MOSFET has two capabilities of the fast switching and high-voltage resistance, and has a smaller size than an IGBT. The current are increased by parallel or parallel-series connecting of MOSFETs. We started the development of a test system whose output current was a 67 A with a pulse width of 1.0 us in 2008. From 2009 to 2011, we succeeded in achieving the output current of a 270 A with a pulse width of 0.8 us by using prototype system. In 2012, by increasing the number of MOSFET, we confirmed the output current of 250 A with a pulse width of 0.5 us, whose case size is a just 210(W) x 160(H) x 300(D) mm. We will report the development status in detail.

MOPWA004

Development of a Non-inductive Ceramic Resistor

injection, pulsed-power, impedance, power-supply

669

T. Sugimoto, K. Fan, K. Ishii, H. Matsumoto
KEK, Ibaraki, Japan
K. Abe
Hitachi Haramachi Electronics Co. Ltd., Hitachishi, Ibaraki, Japan
S. Fukuoka
University of Tsukuba, Graduate School of Pure and Applied Sciences,, Tsukuba, Ibaraki, Japan

Non-inductive ceramic resistors, based on alumina and carbon, are used for impedance matching in the circuit of the J-PARC main ring injection kicker system. The kickers were installed in December 2011, and have been in operation successfully since then. However, discharges at the edge of the ceramic bulk were observed after several weeks’ operation, which increase resistance from O(100) to O(1M). Investigation indicates that poor contact with the rough surface of the ceramic bulk due to irregular shaped spots causes micro-gaps, which trigger the discharge. In order to improve the contact, one type of brazing technology has been experimentally applied to one resistor. Another resistor had an annealed thin copper plate inserted, and both resistors were tested and compared. In this paper, we will describe details of the development of the resistors and give future prospects.

MOPWA007

Operating Experience of Kicker Magnet System in the J-PARC 3GeV RCS

high-voltage, synchrotron, extraction, neutron

678

K. Suganuma, M. Kinsho, T. Togashi, M. Watanabe
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

The J-PARC 3-GeV rapid cycling synchrotron (RCS) has been provided proton beam to the Material and Life Science Facility (MLF)as well as to the 50 GeV Main Ring (MR). Proton beam is accelerated from 181 MeV to 3GeV in the RCS and immediately extracted it to the beam transport line to the MLF and the MR. Extraction kicker system is used for this fast extraction. The RCS has been operated for the neutron and MLF users program from December 23rd, 2008. At the beginning of user operation there were many troubles for the extraction kicker system, especially, thyratron which are used for switch of power supply often caused failure. The beam stop rate due to RCS extraction kicker system was more than 13% in the total beam stop of the J-PARC, establishment and operation experience of the tuning for power supply of the extraction kicker make the beam stop rate less than 0.5% in November 2012. In this paper, we are going to report about daily operation whose main is about operation of thyratron and the maintenance held in summer 2012. And　 We also going to report about the aptitude test of thyratron as a plan of the future.

MOPWA009

Development of a Fast Compensation Kicker System for J-PARC Main-ring Injection

injection, simulation, impedance, power-supply

684

S. Fukuoka
University of Tsukuba, Graduate School of Pure and Applied Sciences,, Tsukuba, Ibaraki, Japan
K. Fan, K. Ishii, H. Matsumoto, T. Sugimoto
KEK, Ibaraki, Japan

Injection system of J-PARC main ring employs four lumped kickers to deflect the incoming beam. The residual field caused by tail and reflection of excitation current increases the closed beam orbit leading to particle loss in high power operation. A correction method using a fast kicker system to compensate the remaining angle is being developed. Doe to the narrow bunch spacing, transmission line kicker is selected to satisfy requirements of fast rise and fall time. The kicker magnet uses ceramic capacitors instead of parallel metal plates to make the magnet compact and reduce the stray inductance. Capacitors are installed in vacuum chamber. A very thin core is used to reduce distributed inductance. A bandwidth is calculated as 160 MHz. A Marx generator using FET switches has been studied, which is able to produce fast rise and fall time as 50 ns. Any pulse shape is generated by choosing switches to fire. A prototype magnet and a power supply have been fabricated for parameters test. In this paper, we will report the details of the system design, analyze the measurement results and give future prospects.

MOPWA013

The New Injection System of the HLS II

septum, pulsed-power, controls, storage-ring

687

L. Shang, Y. Lu, F. Shang, Y.Y. Wang
USTC/NSRL, Hefei, Anhui, People's Republic of China

Funding: The program is funded by NSFC with No. 10875116 and No. 11175181
The 0.8GeV storege ring is being rebuilt in NSRL. The design and construction of the new injection system of the new ring is presented. Kicker magnet, septum magnet and their pulsed power suplies are described. Test results are given. The ceramic chambers, vacuum tank of the septum magnet, system timing and local pulsed power control are also described. The installation and testing of the new system undergoing.

MOPWA026

Fast Magnetic Kickers for the NSLS-II Booster-Synchrotron: Design and Test Results

booster, extraction, injection, vacuum

717

D.A. Shvedov, O. Anchugov, V.A. Kiselev, A.A. Korepanov, S.V. Sinyatkin
BINP SB RAS, Novosibirsk, Russia

For the purpose of realization of single-turn injection and extraction from the NSLS-II booster synchrotron, BINP members created nanosecond non-vacuum ferrite kickers with fronts of pulsed magnetic field of ~ 200 ns, flat-top duration of 300 nsec and its instability of 0.2/1% at most. This paper describes the design of unique kicker magnets with ceramic vacuum chambers with deposited longitudinal strips of titanium nitride (TiN) inside. The paper also presents the results of bench tests of the kickers: oscillograms of current pulse in bus bars, the shape of the pulsed magnetic field, and transverse distribution of the longitudinal field integral in the kicker aperture.

MOPWA027

Pulse Power Supplies for Kicker Magnets of NSLS-2 Booster Ring

injection, extraction, power-supply, booster

720

A.A. Korepanov, A. Akimov, A.A. Pachkov, A. Panov
BINP SB RAS, Novosibirsk, Russia

A set of identical ferrite kicker modules is utilized for the injection and extraction of the NSLS-2 booster ring. The pulse power supplies of these modules are based on the PFN-thyratron design. The pulse current amplitude of up to 4 kA at 300 ns flat top duration and PFN charging voltage of up to 23 kV were achieved on the extraction pulsers. The pulse to pulse repeatability of the output current waveform was measured and made up to 0.05% (σ) at nominal current for the extraction pulsers. The injection pulsers have a specification on the reverse current overshoot to be less than 0.5% of the amplitude. To fulfill this requirement a single turn saturated choke in the thyratron circuit was used. The design and the test results of the power supplies on NSLS-2 site are presented in the paper.

MOPWA030

Upgrade of the LHC Injection Kicker Magnets

vacuum, injection, electron, impedance

729

M.J. Barnes, P. Adraktas, V. Baglin, G. Bregliozzi, S. Calatroni, F. Caspers, H.A. Day, L. Ducimetière, M. Garlaschè, V. Gomes Namora, J.M. Jimenez, N. Magnin, V. Mertens, E. Métral, B. Salvant, M. Taborelli, J.A. Uythoven, W.J.M. Weterings
CERN, Geneva, Switzerland

The two LHC injection kicker systems, comprising 4 magnets per ring, produce a kick of 1.3 T.m with a rise-time of less than 900 ns and a flattop ripple of less than ±0.5%. A beam screen is placed in the aperture of each magnet, to provide a path for the image current of the high intensity LHC beam and screen the ferrite yoke against wake fields. The screen consists of a ceramic tube with conductors in the inner wall. The initially implemented beam screen ensured a low rate of electrical breakdowns while providing an adequate beam coupling impedance. Operation with increasingly higher intensity beams, stable for many hours at a time, now results in substantial heating of the ferrite yoke, sometimes requiring cool down over several hours before the LHC can be refilled. During the long shutdown in 2013/2014 all 8 kicker magnets will be upgraded with an improved beam screen and an increased emissivity of the vacuum tank. In addition equipment adjacent to the injection kickers and various vacuum components will also be modified to help reduce the vacuum pressure in the kickers during high-intensity operation. This paper discusses the upgrades as well as their preparation and planning.

MOPWA031

Beam Induced Ferrite Heating of the LHC Injection Kickers and Proposals for Improved Cooling

vacuum, injection, simulation, impedance

732

M.J. Barnes, S. Calatroni, F. Caspers, L. Ducimetière, M. Garlaschè, V. Gomes Namora, V. Mertens, Z.K. Sobiech, M. Taborelli, J.A. Uythoven, W.J.M. Weterings
CERN, Geneva, Switzerland
H.A. Day
UMAN, Manchester, United Kingdom

The two LHC injection kicker systems produce a kick of 1.3 T.m with a flattop duration variable up to 7860 ns, and rise and fall times of less than 900 ns and 3000 ns, respectively. A beam screen is placed in the aperture of each magnet, which consists of a ceramic tube with conductors in the inner wall. The conductors provide a path for the beam image current and screen the ferrite yoke against wake fields. Recent LHC operation, with high intensity beam stable for many hours, resulted in significant heating of both the ferrite yoke and beam impedance reduction ferrites. For one kicker magnet the ferrite yoke approached its Curie temperature. As a result of a long thermal time-constant the ferrites can require several hours to cool enough to re-inject beam, thus limiting the availability of the LHC. Thermal measurement data has been analysed, a thermal model developed and emissivity measurements carried out. The effects of various measures to improve the ferrite cooling have been simulated, including an improved emissivity of the vacuum tank and active cooling on the outside of the tank.

MOPWA032

Reduction of Surface Flashover of the Beam Screen of the LHC Injection Kickers

injection, vacuum, impedance, simulation

735

M.J. Barnes, P. Adraktas, S. Calatroni, F. Caspers, L. Ducimetière, V. Gomes Namora, V. Mertens, R. Noulibos, M. Taborelli, B. Teissandier, J.A. Uythoven, W.J.M. Weterings
CERN, Geneva, Switzerland

The LHC injection kicker magnets include beam screens to shield the ferrite yokes against wake fields resulting from the high intensity beam. The screening is provided by conductors lodged in the inner wall of a ceramic support tube. Operation with increasingly higher bunch intensity, and narrow bunches, now requires improved ferrite screening. This will be implemented by additional conductors; however the good high-voltage behaviour of the kicker magnets must not be compromised by the supplementary screening. Extensive studies and optimisations have been carried out, to better satisfy the often conflicting requirements for low beam coupling impedance, fast magnetic field rise-time, high vacuum and good high voltage behaviour. A new configuration is proposed which reduces significantly the electric field associated with the screen conductors and the secondary electron yield of the surface of the ceramic tube. Results of high voltage test results are also presented.

MOPWA033

Modelling of Parasitic Inductances of a High Precision Inductive Adder for CLIC

impedance, damping, coupling, emittance

738

J. Holma, M.J. Barnes
CERN, Geneva, Switzerland
S.J. Ovaska
Aalto University, School of Science and Technology, Aalto, Finland

The CLIC study is exploring the scheme for an electron-positron collider with high luminosity and a nominal centre-of-mass energy of 3 TeV. The CLIC pre-damping rings and damping rings will produce, through synchrotron radiation, ultra-low emittance beam with high bunch charge. To avoid beam emittance increase, the damping ring kicker systems must provide extremely flat, high-voltage, pulses. The specifications for the extraction kickers of the DRs are particularly demanding: the flat-top of the pulses must be ±12.5 kV with a combined ripple and droop of not more than ±0.02 % (±2.5 V). An inductive adder is a very promising approach to meeting the specifications. However, the output impedance of the inductive adder needs to be well matched to the system impedance. The primary leakage inductance, which cannot be computed accurately analytically, has a significant effect upon the output impedance of the inductive adder. This paper presents predictions, obtained by modelling the 3D geometry of the adder structure and printed circuit boards using the FastHenry code, for primary leakage inductance.

MOPWA042

The Leakage Current Induced by Stray Capacitance in the Pulse Magnet System

impedance, booster, high-voltage, injection

762

C.S. Chen, C.K. Chan, K.H. Hsu, Y.-H. Liu, C.S. Yang
NSRRC, Hsinchu, Taiwan

A huge amount of current must be provided during the nominal operation of the pulse magnet system in TPS (Taiwan Photon Source). It comes with all kinds of electromagnetic noises, including radiated and conducted EMI (electromagnetic interferences). The primary object of this article is to clarify the paths of induced EMI, especially by means of capacitance induction. Furthermore, some geometrical suggestions which had been tested are listed in this paper as the guidelines of the pulse magnet design. According to the measurement, proper distance and surface area lead to sufficient insulation and reduce the leakage current under the expected value.

MOPWA043

The HV Withstands Test for In Vacuum Booster Kicker

booster, vacuum, injection, extraction

765

Y.-H. Liu, C.K. Chan, C.S. Chen, H.H. Chen, J.-R. Chen, K.H. Hsu, H.P. Hsueh, Y.T. Huang, C.S. Yang
NSRRC, Hsinchu, Taiwan

The maximum driving voltage of TPS booster extraction kicker is close to 30 kV, the HV insulation should be carefully noticed. A DC withstand voltage tester MUSASHI 3802 (Model: IP-701G) is used to test the DC breakdown voltage, which the maximum driving voltage is 37 kV. The 10 mm gap between coil and ferrite is designed in order to increase HV break down voltage. The safety breakdown distance between HV coil and grounding plate was tested in air. Different insulation material with different thickness was tested the breakdown voltage. Thicker than 10 mm ceramic plate could effectively avoid the breakdown occurred with 37 kV DC charging. Thus HV withstand voltage will be higher in vacuum chamber and the insulation with HV will not be the problem.

MOPWA044

TLS Booster Measurement and Observation by New BPM Electronics

booster, synchrotron, quadrupole, extraction

768

P.C. Chiu, J. Chen, Y.-S. Cheng, K.T. Hsu, S.Y. Hsu, K.H. Hu, C.H. Kuo
NSRRC, Hsinchu, Taiwan

Taiwan Light Source (TLS) is a 1.5 GeV synchrotron based light source and its booster synchrotron was delivered in 1992. Due to the new project Taiwan Photon Source proceeded at the same site, some up-to-date device are available now before TPS civil construction complete and temporarily adapted for TLS booster to improve its operations. The major parameters of the TLS booster synchrotron are measured. It also provides a chance to experience for the TPS project booster diagnostic.

MOPWA045

The Pulsed Power Supply System for TPS Project

injection, power-supply, booster, storage-ring

771

C.-S. Fann, C.L. Chen, K.T. Hsu, S.Y. Hsu, A.P. Lee, K.-K. Lin, K.L. Tsai
NSRRC, Hsinchu, Taiwan

The pulsed power supply system for TPS project consists of three types of pulser for booster injection/extraction and storage ring injection. Categorizing by the delivered peak current, pulse shape base-width, they are for: 1) booster kicker: 500 A, square, 1 μs; 2) storage ring kicker: 5 kA, half-sine, 5 μs; 3) transfer line septum: 10 kA, half-sine, 300 μs; respectively. All together, there are 10 units constructed for the associated pulsed magnets. In this report, the test results of the pulsed power supplies will be summarized and the measured results of their performance are presented.

MOPWO022

Design and Manufacturing Description of the Prototype Striplines for the Extraction Kicker of the CLIC Damping Rings

impedance, extraction, damping, vacuum

930

C. Belver-Aguilar, A. Faus-Golfe
IFIC, Valencia, Spain
M.J. Barnes
CERN, Geneva, Switzerland
J. Gómez
Trinos Vacuum Projects, Paterna, Spain
D. Gutiérrez Arribas
Trinos Vacuum Projects, S.L., Paterna - Valencia, Spain
F. Toral
CIEMAT, Madrid, Spain

The Pre-Damping Rings (PDRs) and Damping Rings (DRs) of CLIC are needed to reduce the beam emittances to the small values required for the main linacs. The injection and extraction, from the PDRs and DRs, are carried out by kicker systems. In order to achieve both low beam coupling impedance and reasonable broadband impedance matching to the electrical circuit, striplines have been chosen for the kicker elements. The design of the stripline kicker was previously carried out by modelling the striplines with simulation codes such as HFSS, Quickfield and CST Particle Studio. In order to have a complete analysis of the striplines, the effect of electrodes supports and coaxial feedthroughs have been studied in detail. In this paper, electromagnetic analyses of the complete striplines, including fabrication tolerances, are reported. Furthermore, a new idea for impedance matching is presented.

MOPWO025

Optics and Protection of the Injection and Extraction Regions of the CLIC Damping Rings

extraction, injection, damping, septum

939

R. Apsimon, B. Balhan, M.J. Barnes, J. Borburgh, B. Goddard, Y. Papaphilippou, J.A. Uythoven
CERN, Geneva, Switzerland

The optics design of the injection and extraction regions for the CLIC damping rings is presented. The design defines the parameters for the kicker magnets and septa in these regions and has been optimised to minimise the length of the insertions within the parameter space of the system. Failure modes of the injection and extraction elements are identified and their severity assessed. Protection elements for the injection and extraction regions are optimised based on the conclusions of the failure mode analysis.

MOPWO046

Simulations and Measurements of Beam Losses on LHC Collimators during Beam Abort Failures

simulation, proton, collimation, emittance

996

L. Lari, C. Bracco, R. Bruce, B. Goddard, S. Redaelli, B. Salvachua, G. Valentino
CERN, Geneva, Switzerland
A. Faus-Golfe, L. Lari
IFIC, Valencia, Spain
G. Valentino
University of Malta, Information and Communication Technology, Msida, Malta

Funding: The HiLumi LHC Design Study is included in the HL-LHC project and is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404.
One of the main purposes of tracking simulations for collimation studies is to produce loss maps along the LHC ring, in order to identify the level of local beam losses during nominal and abnormal operation scenarios. The SixTrack program is the standard tracking tool used at CERN to perform these studies. Recently, it was expanded in order to evaluate the proton load on different collimators in case of fast beam failures. Simulations are compared with beam measurements at 4 TeV. Combined failures are assumed which provide worst-case scenarios of the load on tungsten tertiary collimators.

MOPWO047

Studies of Thermal Loads on Collimators for HL-LHC Optics in case of Fast Losses

optics, proton, luminosity, collimation

999

L. Lari, R. Bruce, F. Cerutti
CERN, Geneva, Switzerland
L. Lari
IFIC, Valencia, Spain

Funding: The HiLumi LHC Design Study is included in the HL-LHC project and is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404.
The new layouts for the HL-LHC pose new challenges in terms of proton loads on the collimators around the ring, in particular for the ones of in experimental regions that become critical with squeeze optics. New layouts are under consideration, which foresee updated collimation schemes. Simulations of halo loads for in case of fast failures have been setup with SixTrack in order to determine beam loss distributions for realistic error scenarios. The particle tracking studies might then be interfaced to tools like FLUKA to evaluate the thermal loads on collimators in case of failures. In this paper, the preliminary studies performed for the baseline HL-LHC optics layouts are presented.

MOPWO058

Injection Simulations for TPS Storage Ring

injection, storage-ring, simulation, lattice

1022

C.C. Chiang, P.J. Chou
NSRRC, Hsinchu, Taiwan

We present injection simulations for the TPS (Taiwan Photon Source) storage ring. The baseline lattice of TPS storage ring is a 6-fold structure with 24 double bend cells. For the Step I commissioning, only baseline lattice with dummy chambers are installed. The three double mini-beta-y lattice with insertion devices will be applied during Step II commissioning. The Tracy-2 program is used to simulate the particle motion in 6-D phase space. We adopt lattice models which include errors of alignments and magnet fields. The particle loss due to scraping by chamber limit is recorded in Tracy-2 simulation. We can estimate the radiation distribution of a ring and provide a reference for the shielding design accordingly.

MOPWO078

A Harmonic Kicker Scheme for the Circulator Cooler Ring in the Medium Energy Electron-ion Collider

electron, ion, collider, FEL

1061

E.W. Nissen, A. Hutton, A.J. Kimber
JLAB, Newport News, Virginia, USA

Funding: Supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC05-06OR23177 and DE-AC02-06CH11357.
The current electron cooler design for the proposed Medium Energy Electron-Ion collider (MEIC) at Jefferson Lab utilizes a circulator ring for reuse of the cooling electron bunch up to 100 times to cool the ion beams. This cooler requires a fast kicker system for injecting and extracting individual bunches in the circulator ring. Such a kicker must work at a high repetition rate, up to 7.5 to 75 MHz depending on the number of turns in the recirculator ring. It also must have a very short rise and fall time (of order of 1 ns) such that it will kick an individual bunch without disturbing the others in the ring. Both requirements are orders of magnitude beyond the present state-of-the-art as well as the goals of other on-going kicker R&D programs such as that for the ILC damping rings. In this paper we report a scheme of creating this fast, high repetition rate kicker by combining RF waveforms at multiple frequencies to create a kicker waveform that will, for example, kick every eleventh bunch while leaving the other ten unperturbed. We also present a possible implementation of this scheme as well as discuss its limitations.

TUOAB102

Project X Injector Experiment: Goals, Plan and Status

rfq, ion, cryomodule, solenoid

1093

A.V. Shemyakin, S.D. Holmes, D.E. Johnson, M. Kaducak, R.D. Kephart, V.A. Lebedev, C.S. Mishra, S. Nagaitsev, N. Solyak, R.P. Stanek, V.P. Yakovlev
Fermilab, Batavia, USA
D. Li
LBNL, Berkeley, California, USA
P.N. Ostroumov
ANL, Argonne, USA

Funding: This work was supported by the U.S. DOE under Contract No.DE-AC02-07CH11359
A multi-MW proton facility, Project X, has been proposed and is currently under development at Fermilab. We are carrying out a program of research and development aimed at integrated systems testing of critical components comprising the front end of the Project X. This program is being undertaken as a key component of the larger Project X R&D program. The successful completion of this program will validate the concept for the Project X front end, thereby minimizing a primary technical risk element within Project X. Integrated systems testing, known as the Project X Injector Experiment (PXIE), will be accomplished with a new test facility under construction at Fermilab and will be completed over the period FY12- 17. PXIE will include an H⁻ ion source, a CW 2.1-MeV RFQ and two superconductive RF (SRF) cryomodules providing up to 25 MeV energy gain at an average beam current of 1 mA (upgradable to 2 mA). Successful systems testing will also demonstrate the viability of novel front end technologies that are expected find applications beyond Project X.

Slides TUOAB102 [1.615 MB]

TUPFI027

Energy Deposition Studies for Fast Losses during LHC Injection Failures

injection, proton, quadrupole, alignment

1397

A. Lechner, A. Alnuaimi, C. Bracco, F. Cerutti, A. Christov, L.S. Esposito, N.V. Shetty, V. Vlachoudis
CERN, Geneva, Switzerland

Several instances of injection kicker magnet (MKI) failures have occurred in the first years of LHC operation, leading to misinjections or to accidental kicks of circulating bunches. In a few cases, MKI modules imparted a partial or an increased beam deflection, resulting in grazing bunch impact on beam-intercepting devices and consequently leading to significant secondary showers to downstream accelerator elements. In this study, we investigate different failure occurrences where miskicked bunches were incident on the injection beam stopper (TDI) and on one of the auxiliary injection collimators (TCLIB), respectively. FLUKA shower calculations were performed to quantify the energy deposition in superconducting magnets. Different sections of the LHC insertion regions 2 and 8 were studied, including the separation dipole and the inner triplet downstream of the TDI as well as matching section and dispersion suppressor adjacent to the TCLIB. The obtained results are evaluated in view of quench and damage limits.

TUPFI049

Studies of 10 GeV Decay Ring Design for the International Design Study of the Neutrino Factory

insertion, injection, optics, storage-ring

1457

D.J. Kelliher, C.R. Prior
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
N. Bliss, N.A. Collomb
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
A. Kurup, J. Pasternak
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
J. Pasternak
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
H. Witte
BNL, Upton, Long Island, New York, USA

Due to the discovery of large θ13 the final muon storage energy in the baseline solution of International Design Study for the Neutrino Factory (IDS-NF) has been set at 10 GeV. A new racetrack design has been produced for the decay ring to meet this requirement. The details of lattice design and the beam dynamics calculations are discussed. The feasibility of the injection system for both positive and negative muons into the ring is explored in details.

TUPME032

Update on Beam Induced RF Heating in the LHC

impedance, injection, proton, simulation

1646

B. Salvant, O. Aberle, G. Arduini, R.W. Aßmann, V. Baglin, M.J. Barnes, W. Bartmann, P. Baudrenghien, O.E. Berrig, A. Bertarelli, C. Bracco, E. Bravin, G. Bregliozzi, R. Bruce, F. Carra, F. Caspers, G. Cattenoz, S.D. Claudet, H.A. Day, M. Deile, J. Esteban Müller, P. Fassnacht, M. Garlaschè, L. Gentini, B. Goddard, A. Grudiev, B. Henrist, S. Jakobsen, O.R. Jones, O. Kononenko, G. Lanza, L. Lari, T. Mastoridis, V. Mertens, N. Mounet, E. Métral, A.A. Nosych, J.L. Nougaret, S. Persichelli, A.M. Piguiet, S. Redaelli, F. Roncarolo, G. Rumolo, B. Salvachua, M. Sapinski, R. Schmidt, E.N. Shaposhnikova, L.J. Tavian, M.A. Timmins, J.A. Uythoven, A. Vidal, J. Wenninger, D. Wollmann, M. Zerlauth
CERN, Geneva, Switzerland
H.A. Day
UMAN, Manchester, United Kingdom
L. Lari
IFIC, Valencia, Spain

Since June 2011, the rapid increase of the luminosity performance of the LHC has come at the expense of increased temperature and pressure readings on specific near-beam LHC equipment. In some cases, this beam induced heating has caused delays whilie equipment cools down, beam dumps and even degradation of these devices. This contribution gathers the observations of beam induced heating attributable to beam coupling impedance, their current level of understanding and possible actions that are planned to be implemented during the long shutdown in 2013-2014.

TUPME033

Evaluation of the Beam Coupling Impedance of New beam Screen Designs for the LHC Injection Kicker Magnets

impedance, coupling, injection, resonance

1649

H.A. Day
UMAN, Manchester, United Kingdom
M.J. Barnes, F. Caspers, E. Métral, B. Salvant
CERN, Geneva, Switzerland
R.M. Jones
Cockcroft Institute, Warrington, Cheshire, United Kingdom

The LHC injection kicker magnets (MKIs) have experienced a significant degree of beam induced heating since the beginning of the 2011 due to the increasing intensity stored in the LHC, for long periods of time, and the relatively large broadband impedance of the installed kicker magnets. In this paper we show the sources of impedance in the MKIs, especially the effect that the beam screen dimensions have on the impedance. We show how these alter the power loss, and present an improved beam screen design that improves shielding on the magnet, whilst further improving electrical breakdown.

TUPME050

Performance Comparison of Different System Identification Algorithms for FACET and ATF2

emittance, simulation, linac, alignment

1679

J. Pfingstner, A. Latina, D. Schulte
CERN, Geneva, Switzerland

Good system knowledge is an essential ingredient for the operation of modern accelerator facilities. For example, beam-based alignment algorithms and orbit feedbacks rely strongly on a precise measurement of the orbit response matrix. The quality of the measurement of this matrix can be improved over time by statistically combining the effects of small system excitations with the help of system identification algorithms. These small excitations can be applied in a parasitic mode without stopping the accelerator operation (on-line). In this work, different system identification algorithms are used in simulation studies for the response matrix measurement at ATF2. The results for ATF2 are finally compared with the results for FACET, latter originating from an earlier work.

TUPWA009

Bunch by Bunch Intra-Bunch Feedback System for Curing Transverse Beam Instabilities at the J-PARC MR

feedback, impedance, injection, betatron

1739

O. A. Konstantinova, Y.H. Chin, Y. Kurimoto, T. Obina, M. Okada, K. Takata, M. Tobiyama, T. Toyama
KEK, Ibaraki, Japan
Y. Shobuda
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

At the J-PARC Main Ring (MR), transverse instabilities have been observed during the injection and at the onset of acceleration with large particle losses. The present bunch by bunch feedback system, operating in a narrowband mode, has been effectively suppressing these instabilities, allowing the beam power to reach 230kW with only 400W of particle losses. The observed beam signals show that bunches are still executing complicated intra-bunch oscillations even if the narrowband feedback system is on, though they are not imposing significant particle losses at present. The new and more advanced broadband feedback system has been developed for control of the intra-bunch oscillations and further reduction of particle losses. The elaborate analysis code has been also developed on the MATLAB platform to analyse effects of the broadband feedback system on intra-bunch oscillations. This paper describes the development of these advanced instruments and presents the analysis of the latest beam test results using the MATLAB code.

TUPWA010

A Trial to Reduce the Kicker Impedance of 3-GeV RCS in J-PARC

impedance, resonance, acceleration, status

1742

Y. Shobuda, N. Hayashi, T. Takayanagi
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
Y. Irie
KEK, Ibaraki, Japan
T. Toyama
J-PARC, KEK & JAEA, Ibaraki-ken, Japan

At 3GeV RCS in J-PARC, the kicker impedance has been considered to be the dominant source to cause the beam instability. Recently, experimental studies demonstrate that the beam instability is suppressed by reducing the kicker impedance. In this report, a trial to reduce the kicker impedance is reported.

TUPWA014

The Status of Coupling Impedance Measurement for the CSNS/RCS Extraction Kicker Prototype*

impedance, coupling, simulation, extraction

1754

L. Huang, Y. Li, R.H. Liu, Y.D. Liu, S. Wang, O. Xiao
IHEP, Beijing, People's Republic of China

Rapid Cycling Synchrotron (RCS) of the China Spallation Neutron Source (CSNS) is a high intensity proton accelerator, with average beam power of 100kW. In order to high intensity beam operation, the beam coupling impedance of the extracted kickers must be controlled. Longitudinal and transverse impedance of extracted kicker prototype with power supply had been roughly measured by coaxial-wire and dual-wire methods respectively. At the same time, impedance of window has been analyzed theoretically and simulated based on CST PARTICLE STUDIO.

TUPWA044

Longitudinal Coupled-Bunch Oscillation Studies in the CERN PS

damping, feedback, cavity, emittance

1808

H. Damerau, S. Hancock, M.M. Paoluzzi
CERN, Geneva, Switzerland
M. Migliorati, L. Ventura
Rome University La Sapienza, Roma, Italy

Longitudinal coupled-bunch oscillations are an important limitation for the high-brightness beams accelerated in the CERN PS. Up to the present intensities they are suppressed by a dedicated feedback system limited to the two dominant oscillation modes. In view of the proposed installation of a wide-band feedback kicker cavity within the framework of the LHC Injectors Upgrade project (LIU), measurements have been performed with the existing damping system with the aim of dimensioning the new one. Following the excitation of well-defined oscillation modes, damping times and corresponding longitudinal kick strength are analysed. The paper summarizes the results of the observations and gives an outlook on the expected performance with the new coupled-bunch feedback.

TUPWO004

Preliminary Design of a 4 MW Proton Beam Switchyard for a Neutrino Super Beam Production Facility

target, proton, dipole, quadrupole

1880

E. Bouquerel, M. Dracos, F.R. Osswald
IPHC, Strasbourg Cedex 2, France

Funding: European Commission Framework Programme 7 Design Study: EUROnu, Project Number 212372.
The feasibility of the distribution of 4 MW proton beam power onto a 4-targets horn system for neutrino super-beams production is discussed. A preliminary solution using a pair of bipolar kickers to route the beam onto the targets at a repetition rate of 50 Hz (12.5 Hz per beam line) is proposed. Compensating dipoles would apply symmetry in the system. Magnetic fields induced by these optical elements would not exceed 0.96 T. Studies of the beam envelopes with the code TRANSPORT suggest the use of three quadrupoles per beam line located after the dipoles to focus the 4 mm σ beam onto each target. The length of this switchyard system is estimated to be 29.9 m and 3 m radius.

TUPWO073

Precision Tune, Phase and Beta Function Measurement by Frequency Analysis in RHIC

optics, dipole, betatron, booster

2027

C. Liu, R.L. Hulsart, A. Marusic, R.J. Michnoff, M.G. Minty, P. Thieberger
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The high quality of the RHIC turn-by-turn (TbT) data obtained from the beam position monitor (BPM) system was fully exploited by using two analysis approaches. One is a time domain least square fitting technique and the other one is a frequency domain interpolated Fourier Transform technique. Both methods were applied to 1024-turn data from kicked beam and from continuous coherent excitation experiments. The betatron phase precisions obtained with both methods were ~0.1 degree for the continuous excitation and ~0.2 degree for the impulse excitation. The algorithms of these two analyses and comparison of their results will be presented in this report.

WEOBB203

Design of Phase Feed Forward System in CTF3 and Performance of Fast Beam Phase Monitors

optics, quadrupole, pick-up, target

2097

P. Skowroński, A. Andersson, A. Gerbershagen, E. Ikarios, J. Roberts
CERN, Geneva, Switzerland
P. Burrows, G.B. Christian, A. Gerbershagen, C. Perry, J. Roberts
JAI, Oxford, United Kingdom
P. Burrows, G.B. Christian, A. Gerbershagen, C. Perry
Oxford University, Physics Department, Oxford, Oxon, United Kingdom
A. Ghigo, F. Marcellini
INFN/LNF, Frascati (Roma), Italy
E. Ikarios
National Technical University of Athens, Athens, Greece

Funding: Work supported by the European Commission under the FP7 Research Infrastructures project Eu- CARD, grant agreement no. 227579
The CLIC two beam acceleration technology requires a drive beam phase stability of better than 0.3 deg rms at 12 GHz, corresponding to a timing stability below 50 fs rms. For this reason the CLIC design includes a phase stabilization feed-forward system. It relies on precise beam phase measurement and its subsequent correction in a chicane with help of fast kickers. A prototype of such a system is being installed in CLIC Test Facility CTF3. In this paper we describe in detail its design and implementation. Additionally, we present and discuss the performance of the precision phase monitor prototypes installed at the end of the CTF3 linac, measured with the drive beam.
We would like to acknowledge support of G.Sensolini, A.Zolla (INFN/LNF Frascati), N.S.Chritin and J-M.Scigliuto (CERN) in design and fabrication of components.

Slides WEOBB203 [6.770 MB]

WEPWA013

Injection Scheme into the High Field ILSF Storage Ring

electron, injection, storage-ring, booster

2156

H. Ghasem
IPM, Tehran, Iran
E. Ahmadi, F. Saeidi
ILSF, Tehran, Iran

The injection system into a storage ring of a synchrotron radiation facility significantly affects quality of the electron beam and the radiated x-ray. The extracted 3 GeV electron beam from the booster synchrotron of the ILSF is transferred via the BTS transfer line and injected into the ILSF storage ring based on high field lattice structure. This paper describes the injection procedure into the ILSF storage ring and gives the electron tracking results of the injected beam.

WEPWA051

Extraction Beam Line for Light Sources

extraction, emittance, injection, optics

2232

M. Aiba, M. Böge, T. Garvey, N. Milas, A. Saá Hernández, A. Streun
PSI, Villigen PSI, Switzerland

Most of measurements, with circulating beam in a ring, to determine transverse and longitudinal phase space volume are rather indirect although it is of importance to characterize these beam parameters for better understanding the machine. Direct measurements may be performed when the beam is extracted to a beam line, where destructive methods are available. However, light sources can tolerate internal beam dumping and thus do not have an extraction line in general. We, therefore, propose a diagnostic dedicated extraction line, motivated by precise determination of the geometrical vertical emittance, which can be a few pm or even less and general comparisons of direct and indirect measurements. Such an extraction beam line has been realized in several accelerator facilities, e.g. KEK-ATF. The idea is, however, to equip a compact beam line, which fits into the existing tunnel and allows us to measure transverse and longitudinal emittances. We present possible design of an extraction beam line assuming typical light source parameters.

WEPWA065

A Non-linear Injection Kicker for Diamond Light Source

injection, emittance, quadrupole, septum

2268

T. Pulampong, R. Bartolini
JAI, Oxford, United Kingdom
R. Bartolini
Diamond, Oxfordshire, United Kingdom

Ultra-low emittance lattices will operate with reduced dynamics apertures. New injection schemes are currently investigated in order to guarantee sufficient injection efficiency. A promising candidate is a pulsed kicker with a nonlinear magnetic field. The studies presented in this paper prove that this kicker allows injection with reduced dynamic aperture and provide minimal perturbation of the stored beam during Top-Up injection. Plans to install such a device at the Diamond light source are outlined.

WEPWA070

Design of a Collimation System for the Next Generation Light Source

collimation, gun, undulator, linac

2277

C. Steier, J.M. Byrd, S. De Santis, P. Emma, D. Li, H. Nishimura, C. F. Papadopoulos, H.J. Qian, F. Sannibale
LBNL, Berkeley, California, USA

Funding: This work is supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
The Next Generation Light Source at LBNL will deliver MHz repetition rate electron beams to an array of free electron lasers. Because of the high beam power approaching one MW in such a facility, effective beam collimation is extremely important to minimize radiation damage, prevent quenches of superconducting cavities, limit dose rates outside of the accelerator tunnel and prevent equipment damage. This paper describes the conceptual design of a collimation system, including detailed simulations to verify its effectiveness.

WEPEA016

Upgrade Study of JPARC Main Ring Fast Extraction Septa System

septum, extraction, injection, acceleration

2531

K. Fan, K. Ishii, H. Matsumoto, N. Matsumoto, Y. Morita
KEK, Ibaraki, Japan

The JPARC main ring fast extraction (FX) system has two functions, deliver high power beam to the neutrino experimental facility and dump the beam at any time in case of hardware failures. The present FX system consists of five pair of bipolar kickers and eight pair of bipolar septa. In order to raise the beam power to the design limit, both the beam intensity and the repetition rate will increase gradually. The FX system needs to be upgraded to satisfy the new requirements. The upgrade includes FX orbit optimization and new design of devices. Firstly, the conventional multi-turn low-field septa will be replaced by eddy current type septa. Several configurations of the new design has been studied to realize the requirements of thinner septum, higher field quality, lower leakage and higher mechanical stability. To provide sufficient flat top field for the FX beam, superposition of 3rd harmonic pulse has been employed.

WEPEA029

The SHER-HIAF Ring Lattice Design

injection, quadrupole, ion, lattice

2561

X. Gao, W.P. Chai, G.D. Shen, J. Shi, J.W. Xia, J.C. Yang
IMP, Lanzhou, People's Republic of China

Super Heavy Experimental Ring (SHER) is one of the rings of the next accelerator complex High Intensity Heavy Ion Accelerator Facility (HIAF) at IMP[4]. Here, present ideas of the lattice design for the operation of the large acceptance ring are presented. The SHER ring has to be optimized for e-cooling and the lattice is designed for different modes. First of all, it is designed in the so called isochronous mode as time-of-flight mass spectrometer for short-lived secondary nuclei. Secondly, SHER can also be used to be a storage ring for collecting and cooling the secondary rare isotope beams from the transport line. In order to fulfill it's purpose, the ion optics can be set to different ion optical modes

WEPEA053

Progress with the Upgrade of the SPS for the HL-LHC Era

electron, extraction, simulation, emittance

2624

B. Goddard, T. Argyropoulos, W. Bartmann, H. Bartosik, T. Bohl, F. Caspers, K. Cornelis, H. Damerau, L.N. Drøsdal, L. Ducimetière, J. Esteban Müller, R. Garoby, M. Gourber-Pace, W. Höfle, G. Iadarola, L.K. Jensen, V. Kain, R. Losito, M. Meddahi, A. Mereghetti, V. Mertens, O. Mete, E. Montesinos, Y. Papaphilippou, G. Rumolo, B. Salvant, E.N. Shaposhnikova, M. Taborelli, H. Timko, F.M. Velotti
CERN, Geneva, Switzerland
E. Gianfelice-Wendt
Fermilab, Batavia, USA

The demanding beam performance requirements of the HL-LHC project translate into a set of requirements and upgrade paths for the LHC injector complex. In this paper the performance requirements for the SPS and the known limitations are reviewed in the light of the 2012 operational experience. The various SPS upgrades in progress and still under consideration are described, in addition to the machine studies and simulations performed in 2012. The expected machine performance reach is estimated on the basis of the present knowledge, and the remaining decisions that still need to be made concerning upgrade options are detailed.

WEPEA054

CERN PS Optical Properties Measured with Turn-by-turn Orbit Data

resonance, simulation, optics, extraction

2627

C. Hernalsteens, T. Bach, S.S. Gilardoni, M. Giovannozzi, A. Lachaize, G. Sterbini, R. Tomás, R. Wasef
CERN, Geneva, Switzerland

The performance of the PS has been constantly increasing over the years both in terms of beam parameters (intensity and brightness) and beam manipulations (transverse and longitudinal splitting). This implies a very good knowledge of the linear and non-linear model of the ring. In this paper we report on a detailed campaign of beam measurements based on turn-by-turn orbit data aimed at measuring the optics in several conditions as well as the resonance driving terms. The goal of this study is to assess whether any specific correction system should be envisaged to achieve the required future performance.

WEPEA056

Design and Beam Measurements of Modified Fast Extraction Schemes in the CERN PS for Installing a Dummy Septum to Mitigate Ring Irradiation

extraction, septum, closed-orbit, emittance

2633

C. Hernalsteens, H. Bartosik, L.N. Drøsdal, S.S. Gilardoni, M. Giovannozzi, A. Lachaize, Y. Papaphilippou, A. Ulsroed
CERN, Geneva, Switzerland

The proposed Multi-Turn Extraction (MTE) for the CERN PS allows to reduce the overall extraction losses for high intensity beams. The required longitudinal structure of the proton beam induces unavoidable beam losses at the magnetic extraction septum. The installation of a dummy septum with an appropriate shielding has been proposed to localise losses and to shadow the magnetic septum. Such a device, located in the extraction region, imposes tight constraints on the available beam aperture. Modified extraction schemes have been proposed and in this paper they will be presented and discussed in detail together with the measured performance.

WEPEA057

Numerical Simulations to Evaluate the Performance of CERN PS Dummy Septum to Reduce Irradiation for the Multi-Turn Extraction

septum, extraction, shielding, beam-losses

2636

C. Hernalsteens, S. Damjanovic, S.S. Gilardoni, M. Giovannozzi
CERN, Geneva, Switzerland

The losses created by the proposed Multi-Turn Extraction (MTE) at the CERN PS induces high activation of the magnetic extraction septum due to the de-bunched longitudinal beam structure requested to transfer the beam to the SPS. A mitigation measure is under study aiming at localizing losses in a well-shielded area by shadowing the magnetic extraction septum thanks to septum-like passive device. Such a solution is based on a so-called dummy septum, a blade which absorbs particles during the rise time of the extraction kickers for MTE beams. The efficiency of the scheme is presented in this paper. The quantitative estimate is based on detailed simulations that analyse the beam-matter interaction and provide a determination of the shadowing effect of the dummy septum.

WEPEA077

Applying the 'Simple Accelerator Modelling in Matlab' (SAMM) Code to High Luminosity LHC Upgrade

proton, dipole, dynamic-aperture, quadrupole

2690

K.M. Hock, A. Wolski
Cockcroft Institute, Warrington, Cheshire, United Kingdom
R. Appleby
UMAN, Manchester, United Kingdom

The "Simple Accelerator Modelling in Matlab" (SAMM) code is a set of Matlab routines for modelling beam dynamics in high energy particle accelerators. It includes a set of CUDA codes that can be run on a Graphics Processor Unit. These can be called from SAMM and can speed up tracking simulations by 100 times. To make use of this potential for the computationally intensive LHC upgrade simulations, we have developed additional Matlab and CUDA routines to simulate the full set of elements that are present in the Large Hadron Collider. We present the results of applying these codes to dynamic aperture calculations. These results are benchmarked against PTC and MADX.

WEPFI006

Broad and Narrow Band Feedback Systems at ELSA

feedback, cavity, HOM, damping

2714

M. Schedler, F. Frommberger, P. Hänisch, W. Hillert, C. Reinsch
ELSA, Bonn, Germany

At the Electron Stretcher Facility ELSA of Bonn University, an upgrade of the maximum stored beam current from 20 mA to 200 mA is planned. The storage ring operates applying a fast energy ramp of 6 GeV/s from 1.2 GeV to 3.5 GeV. The intended upgrade is mainly limited due to the excitation of multibunch instabilities. As a countermeasure, we succesfully commissioned state-of-the-art bunch by bunch feedback systems in the longitudinal and the two transverse dimensions. In addition, a narrow band cavity based feedback system for damping the most harmful longitudinal multi bunch mode caused by a HOM of the accelerating cavities is under construction.

WEPME003

Determination of Optics Transfer between the Kicker and BPMs for Transverse Feedback System

feedback, betatron, optics, synchrotron

2923

M. Alhumaidi, A.M. Zoubir
TU Darmstadt, Darmstadt, Germany
J. Grieser
TU Darmstadt, RTR, Darmstadt, Germany

The knowledge of the transfer optics between the positions of the Kicker and the BPMs is required for the calculation of the correction signal in transverse feedback systems. Therefore, using nominal values of the transfer optics with uncertainties leads to feedback quality degradation, and thus beam disturbances. In this work, we propose a method for measuring the phase advances and amplitude scaling between the positions of the kicker and the BPMs. Directly after applying a kick on the beam by means of the kicker, we record the BPM signals. Consequently, we use the Second-Order Blind Identification (SOBI) algorithm to decompose the noised recorded signals into independent sources mixture. Finally, we determine the required optics parameters by identifying and analyzing the betatron oscillation sourced from the kick based on its mixing and temporal patterns. Results for the heavy ions synchrotron SIS 18 at the GSI are shown.

WEPME011

Beam Tests and Plans for the CERN PS Transverse Damper System

emittance, damping, injection, betatron

2947

A. Blas, S.S. Gilardoni, G. Sterbini
CERN, Geneva, Switzerland

The CERN Proton Synchrotron (CPS) has been running without any transverse damping equipment since 1998, thanks to the stabilizing effect of the linear coupling applied between horizontal and vertical planes. Lately, the demand for an active damper strongly emerged for two main reasons: to avoid restrictions as imposed on the betatron tune settings by the linear coupling and to cure instabilities appearing with high intensity beams, especially at the extraction energy. Late in 2012, two electronic prototype units, newly developed for the CPS one-turn-feedback, were programmed with a firmware designed to satisfy the transverse feedback (TFB) requirements in both planes. The main achievements were to automatically adapt the loop delay to the particles' time-of-flight variation within a nanosecond precision and to compensate the changing betatron phase advance between pick-up and kicker during the entire accelerating cycle. With the power equipment limited to the modest bandwidth of 23 MHz and 2 x 800 W per plane, encouraging results were obtained such as fast damping of injection oscillations caused by injection errors, reduction of beam losses along the cycle and damping of instabilities at all CPS energies.

WEPME042

Modelling and Studies for a Wideband Feedback System for Mitigation of Transverse Single Bunch Instabilities

feedback, pick-up, injection, electron

3019

K.S.B. Li, W. Höfle, G. Rumolo
CERN, Geneva, Switzerland
J.M. Cesaratto, J.E. Dusatko, J.D. Fox, M.T.F. Pivi, K.M. Pollock, C.H. Rivetta, O. Turgut
SLAC, Menlo Park, California, USA

As part of the LHC injector upgrade a wideband feedback system is under study for mitigation of coherent single bunch instabilities. This type of system may provide a generic way of shifting the instability threshold to regions that are currently inaccessible, thus, boosting the brightness of future beams. To study the effectiveness of such systems, a numerical model has been developed that constitutes a realistic feedback system including real transfer functions for pickup and kicker, realistic N-tap FIR and IIR filters as well as noise and saturation effects. Simulations of SPS cases have been performed with HeadTail to evaluate the feedback effectiveness in the presence of electron clouds and TMCI. Some results are presented addressing bandwidth limitations, noise issues and amplifier power requirements.

WEPME043

Performance of the LHC Transverse Damper with Bunch Trains

damping, feedback, injection, pick-up

3022

W. Höfle, F. Dubouchet, G. Kotzian, D. Valuch
CERN, Geneva, Switzerland

In 2012 the LHC has operated for Physics with bunch trains at 50 ns spacing. Tests have been performed with the nominal design bunch spacing of 25 ns. The transverse damper has been an essential element to provide beam stability for the multi-bunch beam with up to 1380 bunches used at 50 ns spacing. We report on the experience gained with 50 ns spacing and the improvements in the signal processing tested for the future 25 ns operation. The increase in bandwidth required for 25 ns spacing constituted a particular challenge. The response of the system was carefully measured and the results used to digitally pre-distort the drive signal to compensate for a drop in gain of the power system for higher frequencies. The bunch-by-bunch data collected from the feedback signal path provided valuable information during the 2012 Physics run that can be further explored for beam diagnostics purposes and instability analysis in the future. Performance estimates are given for the 7 TeV run planned for 2015, at 25 ns bunch spacing.

WEPME053

Latest Performance Results from the FONT 5 Intra Train Beam Position Feedback System at ATF

feedback, extraction, cavity, linear-collider

3049

M.R. Davis, D.R. Bett, N. Blaskovic Kraljevic, P. Burrows, G.B. Christian, Y.I. Kim, C. Perry
JAI, Oxford, United Kingdom
R. Apsimon, B. Constance, A. Gerbershagen
CERN, Geneva, Switzerland

A prototype ultra-fast beam-based feedback system for deployment in single-pass beamlines, such as a future lepton collider (ILC or CLIC) or a free-electron laser, has been fabricated and is being tested in the extraction and final focus lines of the Accelerator Test Facility (ATF) at KEK. FONT5 is an intra-train feedback system for stabilising the beam orbit via different methods: a position and angle feedback correction in the extraction line or a vertical feedforward correction applied at the interaction point (IP) . Two systems comprise three stripline beam position monitors (BPMs) and two stripline kickers in the extraction line, two cavity BPMs and a stripline kicker at the IP, a custom FPGA-based digital processing board, custom kicker-drive amplifiers and low-latency analogue front-end BPM processors. Latest results from the experiment are presented. These include beam position correction in the extraction line, as well as preliminary results of beam correction at the IP.

WEPME059

A 4 GS/sec Instability Feedback Processing System for Intra-bunch Instabilities

feedback, controls, pick-up, injection

3067

J.E. Dusatko, J.M. Cesaratto, J.D. Fox, J.J. Olsen, K.M. Pollock, C.H. Rivetta, O. Turgut
SLAC, Menlo Park, California, USA
W. Höfle
CERN, Geneva, Switzerland

Funding: Work supported by the U.S. Department of Energy under contract DE-AC02-76SF00515 and the US LHC Accelerator Research program ( LARP)
We present the architecture and implementation overview of a proof-of-principle digital signal processing system developed to study control of Electron-Cloud and Transverse Mode Coupling Instabilities (TMCI) in the CERN SPS. This system is motivated by intensity increases planned as part of the High Luminosity LHC upgrade. It is based on a reconfigurable processing architecture which samples intra-bunch motion and applies correction signals at a 4GSa/s rate, allowing multiple samples across a single 2ns SPS bunch. This initial demonstration system is a rapidly developed prototype consisting of both commercial and custom-designed hardware that implements feedback control on a single bunch. It contains a high speed ADC and DAC, capable of sampling at up to 4GSa/s, with a 16-tap FIR control filter for each bunch sample slice. Other system features include a timing subsystem to synchronize the sampling to the injection and the bunch 1 markers, the capability of generating arbitrary time domain signals to drive the bunch and diagnostic functions including a snapshot memory for ADC data. This paper describes the design, construction and operational experience of this system.

WEPME060

First Results and Analysis of the Performance of a 4 GS/s Intra-bunch Vertical Feedback System at the SPS

feedback, controls, injection, damping

3070

J.M. Cesaratto, J.E. Dusatko, J.D. Fox, J.J. Olsen, K.M. Pollock, C.H. Rivetta, O. Turgut
SLAC, Menlo Park, California, USA
H. Bartosik, W. Höfle, G. Kotzian, U. Wehrle
CERN, Geneva, Switzerland

Funding: Work supported by the U.S. Department of Energy under contract DE-AC02-76SF00515 and the US LHC Accelerator Research program ( LARP)
We present experimental measurements taken from SPS machine development studies with an intra-bunch feedback channel. These studies use a digital signal processing system to implement general-purpose control algorithms on multiple samples across a single SPS bunch ( for ease of synchronization with the SPS RF frequency a sampling frequency of 3.2 GS/sec. is implemented). These initial studies concentrate on single-bunch motion, and study the vertical betatron motion as the feedback control is varied. The studies are focused on validating simulation models of the beam dynamics with feedback. Time and frequency domain results include excitation and damping of intra-bunch motion with positive and negative feedback. We present an overview of the challenges of intra-bunch feedback, and highlight methods to time-align the pickup and kicker signals within the closed-loop feedback channel.

WEPME061

A Wideband Slotted Kicker Design for SPS Transverse Intra-bunch Feedback

impedance, feedback, coupling, simulation

3073

J.M. Cesaratto, J.D. Fox, C.H. Rivetta
SLAC, Menlo Park, California, USA
D. Alesini, A. Drago, A. Gallo, F. Marcellini, M. Zobov
INFN/LNF, Frascati (Roma), Italy
S. De Santis
LBNL, Berkeley, California, USA
W. Höfle
CERN, Geneva, Switzerland

Funding: Work supported by the U.S. Department of Energy under contract DE-AC02-76SF00515 and the US LHC Accelerator Research Program (LARP) and by the EU FP7 HiLumi LHC - Grant Agreement 284404.
Control and mitigation of transverse beam instabilities caused by electron cloud and TMCI will be essential for the SPS to meet the beam intensity demands for the HL-LHC upgrade. A wideband intra-bunch feedback method is in development, based on a 4 GS/s data acquisition and processing, and with a back end frequency structure extending to 1 GHz. A slotted type kicker, similar to those used for stochastic cooling, has been considered as the terminal element of the feedback chain. It offers the most promising deflecting structure characteristics to meet the system requirements in terms of bandwidth, shunt impedance, and beam coupling impedance. Different types of slotted structures have been explored and simulated, including a ridged waveguide and coaxial type waveguide. In this paper we present our findings and the conceptual design of a vertical SPS wideband kicker consistent with the stay clear, vacuum, frequency band coverage, and peak shunt impedance requirements.

THOBB102

Beam Coupling Impedance Localization Technique Validation and Measurements in the CERN Machines

impedance, quadrupole, lattice, betatron

3106

N. Biancacci, G. Arduini, T. Argyropoulos, H. Bartosik, R. Calaga, K. Cornelis, S.S. Gilardoni, N. Mounet, E. Métral, Y. Papaphilippou, S. Persichelli, G. Rumolo, B. Salvant, G. Sterbini, R. Tomás, R. Wasef
CERN, Geneva, Switzerland
M. Migliorati, L. Palumbo
URLS, Rome, Italy

The beam coupling impedance could lead to limitations in beam brightness and quality, and therefore it needs accurate quantification and continuous monitoring in order to detect and mitigate high impedance sources. In the CERN machines, for example, kickers and collimators are expected to be the main contributors to the total imaginary part of the transverse impedance. In order to detect the other sources, a beam based measurement was developed: from the variation of betatron phase beating with intensity, it is possible to detect the locations of main impedance sources. In this work we present the application of the method with beam measurements in the CERN PS, SPS and LHC.

Slides THOBB102 [7.224 MB]

THPEA041

Performance Improvements of the SPS Internal Beam Dump for the HL-LHC Beam

vacuum, proton, dumping, synchrotron

3231

F.M. Velotti, O. Aberle, C. Bracco, E. Carlier, P. Chiggiato, J.A. Ferreira Somoza, B. Goddard, M. Meddahi, V. Senaj, J.A. Uythoven
CERN, Geneva, Switzerland

The SPS internal beam dump has been designed for beam specifications well below the HL-LHC ones, and for modes of operation which may not be adequate for the HL-LHC era. The present system suffers from several limitations in the allowed intensity and energy range, and its vacuum performance affects nearby high-voltage kicker systems. In this report the limitations of the internal beam dump system are reviewed, and the possible improvements compared. Preliminary upgrade proposals are presented, taking into consideration the expected operational HL-LHC parameters.

THPEA045

Beam Induced Quenches of LHC Magnets

injection, quadrupole, beam-losses, simulation

3243

M. Sapinski, T. Baer, M. Bednarek, G. Bellodi, C. Bracco, R. Bruce, B. Dehning, W. Höfle, A. Lechner, E. Nebot Del Busto, A. Priebe, S. Redaelli, B. Salvachua, R. Schmidt, D. Valuch, A.P. Verweij, J. Wenninger, D. Wollmann, M. Zerlauth
CERN, Geneva, Switzerland

In the years 2009-2013 LHC was operating with the beam energy of 3.5 and 4 TeV instead of the nominal 7 TeV, with the corresponding currents in the superconducting magnets also half nominal. To date only a small number of beam-induced quenches have occurred, with most being due to specially designed quench tests. During normal collider operation with stored beam there has not been a single beam induced quench. This excellent result is mainly explained by the fact that the cleaning of the beam halo worked very well and, in case of beam losses, the beam was dumped before any significant energy was deposited in the magnets. However, conditions are expected to become much tougher after the long LHC shutdown, when the magnets will be working at near nominal currents in the presence of high energy and intensity beams. This paper summarizes the experience to date with beam-induced quenches. It describes the techniques used to generate controlled quench conditions which were used to study the limitations. Results are discussed along with their implication for LHC operation after the first Long Shutdown.

THPEA052

TLS Operation Information Management: Automatic Logging Tools

booster, injection, klystron, linac

3261

C.C. Liang, H.C. Chen, J. Chen, C.K. Chou, S. Fann, K.T. Hsu, K.H. Hu, J.A. Li, D. Lin, T.F. Lin, Y.K. Lin, Y.-C. Liu, C.Y. Wu
NSRRC, Hsinchu, Taiwan
Y.-C. Liu
NTHU, Hsinchu, Taiwan

The Taiwan Light Source (TLS) has been operated in the Top-up mode since October 2005 and has maintained a beam current of 360mA since 2010. Several essential parameters and waveforms are constantly recorded as routine accelerator operation reference. Therefore, five LabVIEW-based data and waveform logging software programs have been developed for the purpose of preliminary diagnose at the TLS. In this report, certain actual cases in regular operation are presented.

THPFI015

In-situ Degassing of the Ferrite Cores in the Extraction Kicker Magnets of the J-PARC 3-GeV RCS

vacuum, target, shielding, quadrupole

3324

J. Kamiya, Y. Hikichi, M. Kinsho, M. Nishikawa, N. Ogiwara, K. Suganuma, T. Yanagibashi
JAEA/J-PARC, Tokai-mura, Japan

Kicker magnets extract the accelerated beam to the beam transport lines in the RCS of the J-PARC. The kicker magnets mainly consist of Ni-Zn ferrite cores and Al alloy plates, and are installed in a vacuum to prevent discharge because a high voltage is applied for a short period. It is important to reduce the outgassing of water vapor from the ferrite cores. Although the kicker magnets have been working well, recently the vacuum quality became a little poor. Thus, we developed the in-situ degassing method for the ferrite cores. This is achieved by directing the heat from the heat source to the kicker magnet and not to the chamber wall. With the test stand we succeeded to flow almost all the heat toward the kicker magnet and to bake out the ferrite cores about 150°C, maintaining the temperature of the chamber wall less than 50°C. As the previous work with TDS measurements revealed that the absorbed water molecules can be easily removed by the bake-out at 100-150°C in a vacuum, the outgassing from the ferrite cores was successfully reduced. The details of the in-situ degassing method will be reported, including the practical method to reduce the outgassing of the working kickers.

THPWO073

European Spallation Source Afterburner Concept

neutron, proton, target, linac

3924

D.P. McGinnis, M. Lindroos, R. Miyamoto
ESS, Lund, Sweden

The European Spallation Source (ESS) is a long pulsed source based on a high power superconducting linac. The long pulse concept is an excellent strategy of maximizing high beam power while minimizing peak power on the target. Chopping in the long pulse concept provides the necessary resolution for many neutron physics applications. However, there are some neutron physics applications in which both peak neutron flux and high resolution are desired. The peak flux of the ESS can be enhanced by placing an accumulator ring at the end of the linac. A bunch by bunch extraction scheme can be used to optimize the proton pulse time profile that maximizes peak neutron flux while minimizing instantaneous beam power on the target.

FRXCA01

Progress in Transverse Feedbacks and Related Diagnostics for Hadron Machines

feedback, injection, hadron, damping

3990

W. Höfle
CERN, Geneva, Switzerland

Today Hadron Accelerators with high intensity and high brightness beams increasingly rely on transverse feedback systems for the control of instabilities and the preservation of the transverse emittance. With particular emphasis, but not limited, to the CERN Hadron Accelerator Chain the progress made in recent years and the performances achieved are reviewed. Hadron colliders such as the LHC represent a particular challenge as they ask for low noise electronic systems in these feedbacks for acceptable emittance growth. Achievements of the LHC transverse feedback system used for damping injection oscillations and to provide stability throughout the cycle are summarized. This includes its use for abort gap and injection cleaning as well as transverse blow-up for diagnostics purposes. Beyond systems already in operation, advances in technology and modern digital signal processing with increasingly higher digitization rates have made systems conceivable to cure intra-bunch motion. With its capabilities to both acquire beam oscillations and to actively excite motion, transverse feedback systems have a large variety of applications for beam diagnostics purposes.

Slides FRXCA01 [4.985 MB]