IPAC2013 - List of Keywords (linear-collider)

Paper	Title	Other Keywords	Page
MOPWA057	Development of a High-resolution, Broad-band, Stripline Beam Position Monitoring System	feedback, monitoring, controls, extraction	804
	G.B. Christian, D.R. Bett, N. Blaskovic Kraljevic, P. Burrows, M.R. Davis, Y.I. Kim, C. Perry JAI, Oxford, United Kingdom R. Apsimon, B. Constance CERN, Geneva, Switzerland P. Burrows, C. Perry Oxford University, Physics Department, Oxford, Oxon, United Kingdom J. Resta IFIC, Valencia, Spain
	A low-latency, sub-micron resolution stripline beam position monitoring system has been developed and tested with beam at the KEK Accelerator Test Facility, where it has been used as part of a feedback system for beam stabilisation. The fast analogue front-end signal processor is based on a single-stage down-mixer and is combined with an FPGA-based system for digitisation and feedback control. A resolution as low as 400 nm has been demonstrated for beam intensities of ~1 nC, with single-pass beam. The latest results of recent modifications to balance the input path lengths to the processor will be discussed. These modifications compensate for the inherent phase sensitivity of the processors, and hence improve the intrinsic resolution, without the need for offline correction. Modifications to the FPGA firmware will also be described, to allow for flexible operation with variable system-synchronous data acquisition at up to 400 MHz, with up to nine data channels of 13-bit width, and a nominal record length of 1 KS/channel/pulse (extensible to a total record length of 120 KS per pulse, for example, for use with long bunch trains or wide-band multi-turn measurements in storage rings).

MOPWA065	Affordable, Short Pulse MARX Modulator	controls, high-voltage, shielding, collider	828
	R.A. Phillips, M.P.J. Gaudreau, M.K. Kempkes, B.E. Simpson Diversified Technologies, Inc., Bedford, Massachusetts, USA J.A. Casey Rockfield Research Inc., Las Vegas, Nevada, USA
	Under a U.S. Department of Energy grant, Diversified Technologies, Inc. (DTI) is developing a short pulse, solid-state Marx modulator for the next generation of klystrons and accelerators. For short-pulse modulators, this Marx topology provides a means to achieve astounding risetimes and flattop control that are simply not available with hard switch or transformer coupled topologies. The design is a high peak-power pulse modulator of greater efficiency than presently available, in the 100 kV to 1 MV range, for currents of 0.1 to 1 kA, pulse lengths of 0.2 to 5.0 us, and rise/fall times 10% of pulse length. A key objective of the development effort is a design which is modular and scalable, yet low cost, and easy to manufacture and maintain. The modulator will be delivered to Yale Beam Physics Laboratory for evaluation, and will be affordable for deployment at other national labs for klystron and modulator evaluation. In this paper, DTI will describe the new design and provide an update on progress.

TUOCB203	In Vacuum High Accuracy Mechanical Positioning System of Nano Resolution Beam Position Monitor at the Interaction Point of ATF2	feedback, vacuum, alignment, collider	1149
	P. Bambade, O.R. Blanco, F. Bogard, P. Cornebise, S. Wallon LAL, Orsay, France T. Tauchi, N. Terunuma KEK, Ibaraki, Japan
	ATF2 is a low energy (1.3GeV) prototype of the final focus system for ILC and CLIC linear collider projects. A major goal of ATF2 is to demonstrate the ability to stabilise the beam position at the interaction point, where the beam can be focused down to about 35 nm. For this purpose, a set of new Beam Position Monitors (BPM) has been designed, with an expected resolution of about 2 nm. These BPMs must be very well aligned with respect to the beam, at the few micron level, to fully exploit their fine resolution. In this paper, the mechanical positioning system which has been developed to enable such a precise alignment is presented. It is based on a set of eight piezo actuators with nanometer range displacement resolution, mounted in a new specially made vacuum chamber. Due to the expected resolution of the piezo actuators, this system also brings a new functionality, the possibility to calibrate the BPMs by mechanically scanning the beam.
	Slides TUOCB203 [2.276 MB]

TUPEA088	Argonne Flexible Linear Collider	collider, linac, klystron, wakefield	1322
	C.-J. Jing, S.P. Antipov, A. Kanareykin, P. Schoessow Euclid TechLabs, LLC, Solon, Ohio, USA M.E. Conde, W. Gai, J.G. Power ANL, Argonne, USA
	We propose a linear collider based on a short rf pulse (~22ns flat top), high gradient (~120MV/m loaded gradient), high frequency (26GHz) two beam accelerator design. This is a modular design and its unique locally repetitive drive beam structure allows a flexible configuration to meet different needs. Major parameters of a conceptual 250GeV linear collider are presented. This preliminary study shows that an efficient (~5% overall), 4MW beam power collider may be achievable. The concept is extendable to the TeV scale.

TUPME020	Design of a TeV Beam Driven Plasma-wakefield Linear Collider	plasma, linac, collider, acceleration	1613
	E. Adli University of Oslo, Oslo, Norway W. An, C. Joshi, W.B. Mori UCLA, Los Angeles, California, USA J.-P. Delahaye, S.J. Gessner, M.J. Hogan, T.O. Raubenheimer SLAC, Menlo Park, California, USA P. Muggli MPI, Muenchen, Germany
	Funding: This work is supported by the Research Council of Norway and U.S. Department of Energy under contract number DE-AC02-76SF00515. A novel design of a 500 GeV c.m. beam-driven PWFA linear collider with effective accelerating gradient on the order of 1 GV/m and extendable in the multi-TeV energy range is presented. The main bunches collide in CW mode at several kHz repetition frequency. They are accelerated and focused with several GV/m fields generated in plasma cells by drive bunches with very good transfer efficiency. The drive bunches are themselves accelerated by a CW superconducting rf recirculating linac. We consider the overall optimizations for the proposed design, compare the efficiency with similar collider designs like ILC and CLIC and we outline the major R&D challenges.

TUPME024	Re-optimization of the Final Focus System Optics with Vertical Chromatic Correction	sextupole, luminosity, collider, optics	1622
	Y. Wang, J. Gao IHEP, Beijing, People's Republic of China P. Bambade LAL, Orsay, France
	Funding: The France China Particle Physics Laboratory (FCPPL) and The National Natural Science Foundation of China (NSFC, Project 11175192) The purpose of the final focus (FF) system of the future linear collider (ILC and CLIC) is to demagnify the beam to the required size at the IP. This can be done in a compact way based on a local chromaticity correction. Two important issues are beam-beam induced radiation effects and the optical correction strategy to mitigate static and dynamic imperfections. For a small enough beam energy spread, we investigate the possibility to get a smaller vertical beam size, at the expense of a larger horizontal beam size, by re-optimising the final focus optics with chromatic correction mainly in the vertical plane. Firstly, we track the beam with MAD-X, with and without chromaticity correction, to estimate the optimum betax and betay values by rematching the linear optics, and cross-check and improve the rematching procedure with MAPCLASS. Then, we study the original design and an alternative simplified optical system, using a set of enlarged betax values, and optimize the sextupoles as a function of betay to minimize the vertical beam size for different assumptions on the energy spread.

TUPME039	The Drive Beam Phase Stability in CTF3 and its Relation to the Bunch Compression Factor	linac, acceleration, pick-up, klystron	1655
	E. Ikarios, A. Andersson, J. Barranco, B. Constance, R. Corsini, A. Gerbershagen, T. Persson, P.K. Skowroński, F. Tecker CERN, Geneva, Switzerland
	The proposed Compact Linear Collider (CLIC) is based on a two-beam acceleration scheme. The energy needed to accelerate a low intensity "main" beam is provided by a high intensity, low energy "drive" beam. The precision and stability of the phase relation between two beams is crucial for the performance of the scheme. The tolerable phase jitter is 0.2 deg rms at 12GHz. For this reason it is fundamental to understand the main possible causes of the drive beam timing jitter. Experimental work aimed at such understanding was done in the CLIC Test Facility (CTF3) where a drive beam with characteristics similar to the CLIC one is produced. Several phase measurements allowed us to conclude that the main source of phase jitter is energy jitter of the beam transformed and amplified into phase jitter when passing through a magnetic chicane. This conclusion is supported by measurements done with different momentum compaction values in the chicane. In this paper the results of these several phase measurements will be presented and compared with expectations.

TUPME049	Status of the Exploration of an Alternative CLIC First Energy Stage Based on Klystrons	klystron, linac, luminosity, collider	1676
	D. Schulte, A. Grudiev, P. Lebrun, G. McMonagle, I. Syratchev, W. Wuensch CERN, Geneva, Switzerland
	The Compact Linear Collider is based on a two-beam scheme to accelerate the main, colliding beams. This scheme allows to reach very high centre-of-mass energies. At low collision energies the main beams could be accelerated by powering the accelerating structures with X-band instead of a second beam. We explore this option and indicate the parameters and conceptual design.

TUPME051	CLIC Final Focus System Alignment and Magnet Tolerances	luminosity, quadrupole, sextupole, feedback	1682
	J. Snuverink, J. Barranco, H. Garcia, Y.I. Levinsen, D. Schulte, R. Tomás CERN, Geneva, Switzerland
	The design requirements for the magnets in the Compact Linear Collider (CLIC) Final Focus System (FFS) are very stringent. In this paper the sensitivity for the misalignment and the magnetic imperfections for the different magnets in the FFS and the crab cavity are presented. Possible mitigation methods are discussed.

TUPME052	Sub-harmonic Buncher Design for the CLIC Drive Beam Injector	coupling, beam-loading, electron, collider	1685
	H. Shaker, S. Döbert, R. Leuxe, S. Sanaye Hajari CERN, Geneva, Switzerland L. Dassa Università di Brescia, Brescia, Italy S. Sanaye Hajari, H. Shaker IPM, Tehran, Iran
	The CLIC (Compact LInear Collider) is based on two beam concept where a high current drive beam provides the energy needed for acceleration of the main beam. The CLIC drive beam accelerator starts with a high current injector using a sophisticated sub-harmonic bunching system. This paper will focus on the design of the Sub Harmonic Bunchers (SHBs) the first RF components of the injector. A backward traveling wave structure has been optimized for this task. It will be shown also how to avoid asymmetrical fields inside the coupler cells and how to compensate beam loading by changing the phase velocity in comparison to the beam velocity.

TUPWO017	Simulation on the Breaking of αx Multiknob Orthogonality in the Presence of Gradient and Coupling Errors and Experimental Investigation	coupling, simulation, quadrupole, sextupole	1919
	S. Bai, J. Gao IHEP, Beijing, People's Republic of China P. Bambade LAL, Orsay, France G.R. White SLAC, Menlo Park, California, USA
	The ATF2 project is the final focus system prototype for ILC and CLIC linear collider projects, with a purpose to reach a 37nm vertical beam size at the interaction point. In beam tuning towards the goal beam size, the presence of a tilt of the IP Shintake monitor fringe pattern with respect to the x-y coordinate system of the beam can break the orthogonality in the main σ34 and σ32 waist corrections required to reduce the vertical beam size at IP. Concerning the method of doing αx scan and measuring the vertical beam size to diagnose the IPBSM fringe tilt or residual σ13, one thing should be studied is to check what could break the orthogonality of the αx knob other than σ13 and the IPBSM fringe tilt. In this paper, we report on the simulation study that check for the breaking of orthogonality of the αx knob in the presence of gradient and coupling errors; to what extent this breaking of orthogonality can go; and also calculate the IPBSM fringe tilt angle from experiment results.

WEIB202	Industrialization of the ILC Project	SRF, linac, cavity, collider	2105
	M.C. Ross SLAC, Menlo Park, California, USA
	Funding: Work supported by U.S. Department of Energy, Contract DE-AC02-76SF00515. The International Linear Collider Global Design Effort (GDE) team completed the Technical Design Report (TDR) in early 2013. The TDR consists of a description of the machine design, a summary of the R&D program carried out in support of the design, a cost estimate and a project plan. The number of high technology components to be fabricated for ILC is large, similar to that built for the Large Hadron Collider, and industrial partners have had an important role throughout the technical development and design period. It is recognized that transfer of new technology to industrial partners and subsequent collaborative development can be difficult. To counter this, the ILC Technical Design Phase (TDP) team arranged a series of vendor visits, component development contracts, workshop satellite meetings and industrial production study contracts. The GDE collaboration provided the framework for development through an agreed-upon performance parameter set and project implementation scheme. The latter includes a ‘plug-compatibility’ policy that promotes innovation as long as specified interface conditions are met. In this paper we show the evolution of the technology from the labs where it was developed to the companies where high performance cavities are now routinely produced. The longest journey: the LHC dipoles arrive on time. http://cerncourier.com/cws/article/cern/29723 ** Office of High Energy Physics Accelerator R&D Task Force Report http://www.acceleratorsamerica.org/report/accelerator_task_force_report.pdf
	Slides WEIB202 [5.181 MB]

WEPWO015	Electron Beam Welding for High Gradient Superconducting Cavity	electron, cavity, superconducting-cavity, collider	2346
	T. Kubo, Y. Ajima, H. Hayano, H. Inoue, S. Kato, T. Saeki, M. Sawabe, K. Umemori, Y. Watanabe, S. Yamaguchi, M. Yamanaka KEK, Ibaraki, Japan Y. Iwashita Kyoto ICR, Uji, Kyoto, Japan T. Nagata ULVAC, Inc., Tsukuba, Japan
	Relations between electron beam welding parameters and appearances of weld beads are studied. It was found that a beam generator position and a welding direction affect a geometry of weld bead dramatically. Carbon including contaminants found after the chemistry are also commented.

WEPFI032	New Calibration Method for Radial Line Experiment	wakefield, collider, cavity, damping	2774
	X.W. Wu, H.B. Chen, J. Shi, H. Zha TUB, Beijing, People's Republic of China
	A radial line experiment is proposed to test the SiC load disks of the choke-mode structure. However, the general calibration cannot work out in this situation due to lack of matched load. A new calibration method named multi-offset short calibration is proposed. The principles of the method and the calibration steps involved are presented and the results of actual experimentation are used to validate the method. The results show multi-offset short calibration is a feasible method and that this method can provide a viable calibration scheme for radial line measurements.

WEPFI080	Waveguide Component R&D for the ILC	klystron, linac, cavity, coupling	2881
	C.D. Nantista, C. Adolphsen, G.B. Bowden, A.A. Haase, B.D. McKee, F.Y. Wang SLAC, Menlo Park, California, USA
	Funding: Work supported by the U.S. Department of Energy under contract DE-AC02-76SF00515. Several years of effort have gone into refining the design of the International Linear Collider. The direction the design has evolved in response to driving considerations has resulted in a more sophisticated waveguide system for delivering RF power to the cavities. In particular, the desire to eliminate parallel service tunnels along the main linacs led to the proposal of the Klystron Cluster Scheme (KCS), involving plumbing the combined power from groups of klystrons down from the surface at several locations in overmoded waveguide. Additionally, to increase superconducting cavity yield, the acceptance criteria were relaxed to encompass a ±20% range in sustainable operating gradient, which must be accommodated by tailoring of the RF power distribution. Designs and prototype testing of some of the novel waveguide components developed to allow these changes are described here. Christopher Nantista and Chris Adolphsen, “Klystron Cluster Scheme for ILC High Power RF Distribution,” presented at the 2009 Particle Accel. Conf., Vancouver, B.C., Canada, May 2009.

WEPFI083	High Power Tests of the 2-Pin Waveguide Structures	factory, collider, site, electron	2890
	F.Y. Wang, Z. Li SLAC, Menlo Park, California, USA
	An X-band Two-Pin Waveguide Structure has been designed to study the influence of power flow on rf breakdown. Three different sets of pins will be tested at SLAC. These sets were designed to achieve a similar peak surface electric field on one of the pins for input rf power levels that vary by about an order of magnitude (the other pin is used for matching). Two sets of pins have been tested so far, and the breakdown rate was found to be strongly dependent on the power flow. In this paper, we review the experimental setup, the complete set of results and their implications.

WEPFI086	Normal Conducting Radio Frequency X-band Deflecting Cavity Fabrication, Validation and Tuning	cavity, electron, vacuum, collider	2899
	R.B. Agustsson, L. Faillace, A.Y. Murokh, E. Spranza, S. Storms RadiaBeam, Santa Monica, USA D. Alesini INFN/LNF, Frascati (Roma), Italy V.A. Dolgashev, J.R. Lewandowski SLAC, Menlo Park, California, USA J.B. Rosenzweig UCLA, Los Angeles, California, USA V. Yakimenko BNL, Upton, Long Island, New York, USA
	An X-band Traveling wave Deflector mode cavity (XTD) has been developed, fabricated, tuned and characterized by Radiabeam Technologies to perform longitudinal measurement of the sub-picosecond ultra-relativistic electron beams. The device is optimized for the 100 MeV electron beam parameters at the Accelerator Test Facility (ATF) at Brookhaven National Laboratory, and is scalable to higher energies. The XTD is designed to operate at 11.424 GHz, and features short filling time, femtosecond resolution, and a small footprint. RF design, structure fabrication, cold testing and tuning results are presented.

WEPME045	Development and Validation of a Multipoint Based Laser Alignment System for CLIC	laser, alignment, linac, target	3028
	G. Stern, J. Kemppinen, F. Lackner, H. Mainaud Durand, D. Piedigrossi, J. Sandomierski, M. Sosin CERN, Geneva, Switzerland A. Geiger, S. Guillaume ETH, Zurich, Switzerland
	Alignment is one of the major challenges within CLIC study, since all accelerator components have to be aligned with accuracy up to 10 μm over sliding windows of 200 m. So far, the straight line reference concept has been based on stretched wires coupled with Wire Positioning Sensors. This concept should be validated through inter-comparison with an alternative solution. This paper proposes an alternative concept where laser beam acts as straight line reference and optical shutters coupled with cameras visualise the beam. The principle was first validated by a series of tests using low-cost components. Yet, in order to further decrease measurement uncertainty in this validation step, a high-precision automatised micrometric table and reference targets have been added to the setup. The paper presents the results obtained with this new equipment, in terms of measurement precision. In addition, the paper gives an overview of first tests done at long distance (up to 53 m), having emphasis on beam divergence.

WEPME046	Alignment Challenges for a Future Linear Collider	alignment, linac, collider, laser	3031
	H. Mainaud Durand, D.P. Missiaen, G. Stern CERN, Geneva, Switzerland
	The preservation of ultra-low emittances in the main linac and Beam Delivery System area is one of the main challenges for linear colliders. This requires alignment tolerances never achieved before at that scale, down to the micrometre level. As a matter of fact, in the LHC, the goal for the smoothing of the components was to obtain a 1σ deviation with respect to a smooth curve of 0.15 mm in a 150 m long sliding window, while for the CLIC project for example, it corresponds to 10 micrometres over a sliding window of 200m in the Beam Delivery System area. Two complementary strategies are being studied to fulfill these requirements: the development and validation of long range alignment systems to propagate precision and accuracy over a few hundreds of metres and short range alignment systems over a few metres. The studies undertaken, with associated test setups and the latest results will be detailed, as well as their application for the alignment of both CLIC and ILC colliders.

WEPME053	Latest Performance Results from the FONT 5 Intra Train Beam Position Feedback System at ATF	feedback, kicker, extraction, cavity	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.

THPFI061	Design Process of the Interlock Systems for the Compact Linear Collider	collider, controls, target, hadron	3433
	P. Nouvel, M. Jonker, B. Puccio CERN, Geneva, Switzerland H. Tap INPT, Toulouse, France
	Interlock systems are a critical part for the machine protection of linear colliders. Their goal is to inhibit the next pulse either on failure of critical equipment and/or on low beam quality evaluation. This paper presents the on-going process to validate design choices for the Compact Linear Collider (CLIC) interlock systems. The design process starts by establishing requirements. In mission-critical system case, they are mainly focused on the dependability. Moreover, the new concept of fast beam quality analysis has been introduced into the CLIC interlock system and will be discussed in this paper. To support the design process, experimentation on this concept has been launched. In addition, a hardware demonstration of the interlock systems has been set-up. It allows validating the design in concordance with the requirements.

THPME043	Prototype Adjustable Permanent Magnet Quadrupoles For CLIC	quadrupole, permanent-magnet, collider, magnet-design	3606
	B.J.A. Shepherd, J.A. Clarke STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom A. Bartalesi, M. Modena, M. Struik CERN, Geneva, Switzerland N.A. Collomb STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
	The 42km long Drive Beam Decelerator for the Compact Linear Collider (CLIC) requires over 41,000 quadrupole magnets. ASTeC and CERN are investigating the possibility of permanent magnet quadrupoles (PMQs) to reduce running costs and heat load inside the CLIC tunnel. A prototype of a high-strength adjustable PMQ has been built, based on a simple concept using two moving sections each containing a pair of large permanent magnets. The gradient can be adjusted within a range of 15-60 T/m (3-15T integrated gradient). The prototype has undergone extensive magnetic testing at Daresbury Laboratory and CERN, and performs well in line with expectations. A prototype of the low-strength version (0.9-9T) is currently under construction.

Paper

Title

Other Keywords

Page

MOPWA057

Development of a High-resolution, Broad-band, Stripline Beam Position Monitoring System

feedback, monitoring, controls, extraction

804

G.B. Christian, D.R. Bett, N. Blaskovic Kraljevic, P. Burrows, M.R. Davis, Y.I. Kim, C. Perry
JAI, Oxford, United Kingdom
R. Apsimon, B. Constance
CERN, Geneva, Switzerland
P. Burrows, C. Perry
Oxford University, Physics Department, Oxford, Oxon, United Kingdom
J. Resta
IFIC, Valencia, Spain

A low-latency, sub-micron resolution stripline beam position monitoring system has been developed and tested with beam at the KEK Accelerator Test Facility, where it has been used as part of a feedback system for beam stabilisation. The fast analogue front-end signal processor is based on a single-stage down-mixer and is combined with an FPGA-based system for digitisation and feedback control. A resolution as low as 400 nm has been demonstrated for beam intensities of ~1 nC, with single-pass beam. The latest results of recent modifications to balance the input path lengths to the processor will be discussed. These modifications compensate for the inherent phase sensitivity of the processors, and hence improve the intrinsic resolution, without the need for offline correction. Modifications to the FPGA firmware will also be described, to allow for flexible operation with variable system-synchronous data acquisition at up to 400 MHz, with up to nine data channels of 13-bit width, and a nominal record length of 1 KS/channel/pulse (extensible to a total record length of 120 KS per pulse, for example, for use with long bunch trains or wide-band multi-turn measurements in storage rings).

MOPWA065

Affordable, Short Pulse MARX Modulator

controls, high-voltage, shielding, collider

828

R.A. Phillips, M.P.J. Gaudreau, M.K. Kempkes, B.E. Simpson
Diversified Technologies, Inc., Bedford, Massachusetts, USA
J.A. Casey
Rockfield Research Inc., Las Vegas, Nevada, USA

Under a U.S. Department of Energy grant, Diversified Technologies, Inc. (DTI) is developing a short pulse, solid-state Marx modulator for the next generation of klystrons and accelerators. For short-pulse modulators, this Marx topology provides a means to achieve astounding risetimes and flattop control that are simply not available with hard switch or transformer coupled topologies. The design is a high peak-power pulse modulator of greater efficiency than presently available, in the 100 kV to 1 MV range, for currents of 0.1 to 1 kA, pulse lengths of 0.2 to 5.0 us, and rise/fall times 10% of pulse length. A key objective of the development effort is a design which is modular and scalable, yet low cost, and easy to manufacture and maintain. The modulator will be delivered to Yale Beam Physics Laboratory for evaluation, and will be affordable for deployment at other national labs for klystron and modulator evaluation. In this paper, DTI will describe the new design and provide an update on progress.

TUOCB203

In Vacuum High Accuracy Mechanical Positioning System of Nano Resolution Beam Position Monitor at the Interaction Point of ATF2

feedback, vacuum, alignment, collider

1149

P. Bambade, O.R. Blanco, F. Bogard, P. Cornebise, S. Wallon
LAL, Orsay, France
T. Tauchi, N. Terunuma
KEK, Ibaraki, Japan

ATF2 is a low energy (1.3GeV) prototype of the final focus system for ILC and CLIC linear collider projects. A major goal of ATF2 is to demonstrate the ability to stabilise the beam position at the interaction point, where the beam can be focused down to about 35 nm. For this purpose, a set of new Beam Position Monitors (BPM) has been designed, with an expected resolution of about 2 nm. These BPMs must be very well aligned with respect to the beam, at the few micron level, to fully exploit their fine resolution. In this paper, the mechanical positioning system which has been developed to enable such a precise alignment is presented. It is based on a set of eight piezo actuators with nanometer range displacement resolution, mounted in a new specially made vacuum chamber. Due to the expected resolution of the piezo actuators, this system also brings a new functionality, the possibility to calibrate the BPMs by mechanically scanning the beam.

Slides TUOCB203 [2.276 MB]

TUPEA088

Argonne Flexible Linear Collider

collider, linac, klystron, wakefield

1322

C.-J. Jing, S.P. Antipov, A. Kanareykin, P. Schoessow
Euclid TechLabs, LLC, Solon, Ohio, USA
M.E. Conde, W. Gai, J.G. Power
ANL, Argonne, USA

We propose a linear collider based on a short rf pulse (~22ns flat top), high gradient (~120MV/m loaded gradient), high frequency (26GHz) two beam accelerator design. This is a modular design and its unique locally repetitive drive beam structure allows a flexible configuration to meet different needs. Major parameters of a conceptual 250GeV linear collider are presented. This preliminary study shows that an efficient (~5% overall), 4MW beam power collider may be achievable. The concept is extendable to the TeV scale.

TUPME020

Design of a TeV Beam Driven Plasma-wakefield Linear Collider

plasma, linac, collider, acceleration

1613

E. Adli
University of Oslo, Oslo, Norway
W. An, C. Joshi, W.B. Mori
UCLA, Los Angeles, California, USA
J.-P. Delahaye, S.J. Gessner, M.J. Hogan, T.O. Raubenheimer
SLAC, Menlo Park, California, USA
P. Muggli
MPI, Muenchen, Germany

Funding: This work is supported by the Research Council of Norway and U.S. Department of Energy under contract number DE-AC02-76SF00515.
A novel design of a 500 GeV c.m. beam-driven PWFA linear collider with effective accelerating gradient on the order of 1 GV/m and extendable in the multi-TeV energy range is presented. The main bunches collide in CW mode at several kHz repetition frequency. They are accelerated and focused with several GV/m fields generated in plasma cells by drive bunches with very good transfer efficiency. The drive bunches are themselves accelerated by a CW superconducting rf recirculating linac. We consider the overall optimizations for the proposed design, compare the efficiency with similar collider designs like ILC and CLIC and we outline the major R&D challenges.

TUPME024

Re-optimization of the Final Focus System Optics with Vertical Chromatic Correction

sextupole, luminosity, collider, optics

1622

Y. Wang, J. Gao
IHEP, Beijing, People's Republic of China
P. Bambade
LAL, Orsay, France

Funding: The France China Particle Physics Laboratory (FCPPL) and The National Natural Science Foundation of China (NSFC, Project 11175192)
The purpose of the final focus (FF) system of the future linear collider (ILC and CLIC) is to demagnify the beam to the required size at the IP. This can be done in a compact way based on a local chromaticity correction. Two important issues are beam-beam induced radiation effects and the optical correction strategy to mitigate static and dynamic imperfections. For a small enough beam energy spread, we investigate the possibility to get a smaller vertical beam size, at the expense of a larger horizontal beam size, by re-optimising the final focus optics with chromatic correction mainly in the vertical plane. Firstly, we track the beam with MAD-X, with and without chromaticity correction, to estimate the optimum betax and betay values by rematching the linear optics, and cross-check and improve the rematching procedure with MAPCLASS. Then, we study the original design and an alternative simplified optical system, using a set of enlarged betax values, and optimize the sextupoles as a function of betay to minimize the vertical beam size for different assumptions on the energy spread.

TUPME039

The Drive Beam Phase Stability in CTF3 and its Relation to the Bunch Compression Factor

linac, acceleration, pick-up, klystron

1655

E. Ikarios, A. Andersson, J. Barranco, B. Constance, R. Corsini, A. Gerbershagen, T. Persson, P.K. Skowroński, F. Tecker
CERN, Geneva, Switzerland

The proposed Compact Linear Collider (CLIC) is based on a two-beam acceleration scheme. The energy needed to accelerate a low intensity "main" beam is provided by a high intensity, low energy "drive" beam. The precision and stability of the phase relation between two beams is crucial for the performance of the scheme. The tolerable phase jitter is 0.2 deg rms at 12GHz. For this reason it is fundamental to understand the main possible causes of the drive beam timing jitter. Experimental work aimed at such understanding was done in the CLIC Test Facility (CTF3) where a drive beam with characteristics similar to the CLIC one is produced. Several phase measurements allowed us to conclude that the main source of phase jitter is energy jitter of the beam transformed and amplified into phase jitter when passing through a magnetic chicane. This conclusion is supported by measurements done with different momentum compaction values in the chicane. In this paper the results of these several phase measurements will be presented and compared with expectations.

TUPME049

Status of the Exploration of an Alternative CLIC First Energy Stage Based on Klystrons

klystron, linac, luminosity, collider

1676

D. Schulte, A. Grudiev, P. Lebrun, G. McMonagle, I. Syratchev, W. Wuensch
CERN, Geneva, Switzerland

The Compact Linear Collider is based on a two-beam scheme to accelerate the main, colliding beams. This scheme allows to reach very high centre-of-mass energies. At low collision energies the main beams could be accelerated by powering the accelerating structures with X-band instead of a second beam. We explore this option and indicate the parameters and conceptual design.

TUPME051

CLIC Final Focus System Alignment and Magnet Tolerances

luminosity, quadrupole, sextupole, feedback

1682

J. Snuverink, J. Barranco, H. Garcia, Y.I. Levinsen, D. Schulte, R. Tomás
CERN, Geneva, Switzerland

The design requirements for the magnets in the Compact Linear Collider (CLIC) Final Focus System (FFS) are very stringent. In this paper the sensitivity for the misalignment and the magnetic imperfections for the different magnets in the FFS and the crab cavity are presented. Possible mitigation methods are discussed.

TUPME052

Sub-harmonic Buncher Design for the CLIC Drive Beam Injector

coupling, beam-loading, electron, collider

1685

H. Shaker, S. Döbert, R. Leuxe, S. Sanaye Hajari
CERN, Geneva, Switzerland
L. Dassa
Università di Brescia, Brescia, Italy
S. Sanaye Hajari, H. Shaker
IPM, Tehran, Iran

The CLIC (Compact LInear Collider) is based on two beam concept where a high current drive beam provides the energy needed for acceleration of the main beam. The CLIC drive beam accelerator starts with a high current injector using a sophisticated sub-harmonic bunching system. This paper will focus on the design of the Sub Harmonic Bunchers (SHBs) the first RF components of the injector. A backward traveling wave structure has been optimized for this task. It will be shown also how to avoid asymmetrical fields inside the coupler cells and how to compensate beam loading by changing the phase velocity in comparison to the beam velocity.

TUPWO017

Simulation on the Breaking of αx Multiknob Orthogonality in the Presence of Gradient and Coupling Errors and Experimental Investigation

coupling, simulation, quadrupole, sextupole

1919

S. Bai, J. Gao
IHEP, Beijing, People's Republic of China
P. Bambade
LAL, Orsay, France
G.R. White
SLAC, Menlo Park, California, USA

The ATF2 project is the final focus system prototype for ILC and CLIC linear collider projects, with a purpose to reach a 37nm vertical beam size at the interaction point. In beam tuning towards the goal beam size, the presence of a tilt of the IP Shintake monitor fringe pattern with respect to the x-y coordinate system of the beam can break the orthogonality in the main σ34 and σ32 waist corrections required to reduce the vertical beam size at IP. Concerning the method of doing αx scan and measuring the vertical beam size to diagnose the IPBSM fringe tilt or residual σ13, one thing should be studied is to check what could break the orthogonality of the αx knob other than σ13 and the IPBSM fringe tilt. In this paper, we report on the simulation study that check for the breaking of orthogonality of the αx knob in the presence of gradient and coupling errors; to what extent this breaking of orthogonality can go; and also calculate the IPBSM fringe tilt angle from experiment results.

WEIB202

Industrialization of the ILC Project

SRF, linac, cavity, collider

2105

M.C. Ross
SLAC, Menlo Park, California, USA

Funding: Work supported by U.S. Department of Energy, Contract DE-AC02-76SF00515.
The International Linear Collider Global Design Effort (GDE) team completed the Technical Design Report (TDR) in early 2013. The TDR consists of a description of the machine design, a summary of the R&D program carried out in support of the design, a cost estimate and a project plan. The number of high technology components to be fabricated for ILC is large, similar to that built for the Large Hadron Collider*, and industrial partners have had an important role throughout the technical development and design period. It is recognized that transfer of new technology to industrial partners and subsequent collaborative development can be difficult**. To counter this, the ILC Technical Design Phase (TDP) team arranged a series of vendor visits, component development contracts, workshop satellite meetings and industrial production study contracts. The GDE collaboration provided the framework for development through an agreed-upon performance parameter set and project implementation scheme. The latter includes a ‘plug-compatibility’ policy that promotes innovation as long as specified interface conditions are met. In this paper we show the evolution of the technology from the labs where it was developed to the companies where high performance cavities are now routinely produced.
* The longest journey: the LHC dipoles arrive on time.
http://cerncourier.com/cws/article/cern/29723
** Office of High Energy Physics Accelerator R&D Task Force Report
http://www.acceleratorsamerica.org/report/accelerator_task_force_report.pdf

Slides WEIB202 [5.181 MB]

WEPWO015

Electron Beam Welding for High Gradient Superconducting Cavity

electron, cavity, superconducting-cavity, collider

2346

T. Kubo, Y. Ajima, H. Hayano, H. Inoue, S. Kato, T. Saeki, M. Sawabe, K. Umemori, Y. Watanabe, S. Yamaguchi, M. Yamanaka
KEK, Ibaraki, Japan
Y. Iwashita
Kyoto ICR, Uji, Kyoto, Japan
T. Nagata
ULVAC, Inc., Tsukuba, Japan

Relations between electron beam welding parameters and appearances of weld beads are studied. It was found that a beam generator position and a welding direction affect a geometry of weld bead dramatically. Carbon including contaminants found after the chemistry are also commented.

WEPFI032

New Calibration Method for Radial Line Experiment

wakefield, collider, cavity, damping

2774

X.W. Wu, H.B. Chen, J. Shi, H. Zha
TUB, Beijing, People's Republic of China

A radial line experiment is proposed to test the SiC load disks of the choke-mode structure. However, the general calibration cannot work out in this situation due to lack of matched load. A new calibration method named multi-offset short calibration is proposed. The principles of the method and the calibration steps involved are presented and the results of actual experimentation are used to validate the method. The results show multi-offset short calibration is a feasible method and that this method can provide a viable calibration scheme for radial line measurements.

WEPFI080

Waveguide Component R&D for the ILC

klystron, linac, cavity, coupling

2881

C.D. Nantista, C. Adolphsen, G.B. Bowden, A.A. Haase, B.D. McKee, F.Y. Wang
SLAC, Menlo Park, California, USA

Funding: Work supported by the U.S. Department of Energy under contract DE-AC02-76SF00515.
Several years of effort have gone into refining the design of the International Linear Collider. The direction the design has evolved in response to driving considerations has resulted in a more sophisticated waveguide system for delivering RF power to the cavities. In particular, the desire to eliminate parallel service tunnels along the main linacs led to the proposal of the Klystron Cluster Scheme (KCS)*, involving plumbing the combined power from groups of klystrons down from the surface at several locations in overmoded waveguide. Additionally, to increase superconducting cavity yield, the acceptance criteria were relaxed to encompass a ±20% range in sustainable operating gradient, which must be accommodated by tailoring of the RF power distribution. Designs and prototype testing of some of the novel waveguide components developed to allow these changes are described here.
* Christopher Nantista and Chris Adolphsen, “Klystron Cluster Scheme for ILC High Power RF Distribution,” presented at the 2009 Particle Accel. Conf., Vancouver, B.C., Canada, May 2009.

WEPFI083

High Power Tests of the 2-Pin Waveguide Structures

factory, collider, site, electron

2890

F.Y. Wang, Z. Li
SLAC, Menlo Park, California, USA

An X-band Two-Pin Waveguide Structure has been designed to study the influence of power flow on rf breakdown. Three different sets of pins will be tested at SLAC. These sets were designed to achieve a similar peak surface electric field on one of the pins for input rf power levels that vary by about an order of magnitude (the other pin is used for matching). Two sets of pins have been tested so far, and the breakdown rate was found to be strongly dependent on the power flow. In this paper, we review the experimental setup, the complete set of results and their implications.

WEPFI086

Normal Conducting Radio Frequency X-band Deflecting Cavity Fabrication, Validation and Tuning

cavity, electron, vacuum, collider

2899

R.B. Agustsson, L. Faillace, A.Y. Murokh, E. Spranza, S. Storms
RadiaBeam, Santa Monica, USA
D. Alesini
INFN/LNF, Frascati (Roma), Italy
V.A. Dolgashev, J.R. Lewandowski
SLAC, Menlo Park, California, USA
J.B. Rosenzweig
UCLA, Los Angeles, California, USA
V. Yakimenko
BNL, Upton, Long Island, New York, USA

An X-band Traveling wave Deflector mode cavity (XTD) has been developed, fabricated, tuned and characterized by Radiabeam Technologies to perform longitudinal measurement of the sub-picosecond ultra-relativistic electron beams. The device is optimized for the 100 MeV electron beam parameters at the Accelerator Test Facility (ATF) at Brookhaven National Laboratory, and is scalable to higher energies. The XTD is designed to operate at 11.424 GHz, and features short filling time, femtosecond resolution, and a small footprint. RF design, structure fabrication, cold testing and tuning results are presented.

WEPME045

Development and Validation of a Multipoint Based Laser Alignment System for CLIC

laser, alignment, linac, target

3028

G. Stern, J. Kemppinen, F. Lackner, H. Mainaud Durand, D. Piedigrossi, J. Sandomierski, M. Sosin
CERN, Geneva, Switzerland
A. Geiger, S. Guillaume
ETH, Zurich, Switzerland

Alignment is one of the major challenges within CLIC study, since all accelerator components have to be aligned with accuracy up to 10 μm over sliding windows of 200 m. So far, the straight line reference concept has been based on stretched wires coupled with Wire Positioning Sensors. This concept should be validated through inter-comparison with an alternative solution. This paper proposes an alternative concept where laser beam acts as straight line reference and optical shutters coupled with cameras visualise the beam. The principle was first validated by a series of tests using low-cost components. Yet, in order to further decrease measurement uncertainty in this validation step, a high-precision automatised micrometric table and reference targets have been added to the setup. The paper presents the results obtained with this new equipment, in terms of measurement precision. In addition, the paper gives an overview of first tests done at long distance (up to 53 m), having emphasis on beam divergence.

WEPME046

Alignment Challenges for a Future Linear Collider

alignment, linac, collider, laser

3031

H. Mainaud Durand, D.P. Missiaen, G. Stern
CERN, Geneva, Switzerland

The preservation of ultra-low emittances in the main linac and Beam Delivery System area is one of the main challenges for linear colliders. This requires alignment tolerances never achieved before at that scale, down to the micrometre level. As a matter of fact, in the LHC, the goal for the smoothing of the components was to obtain a 1σ deviation with respect to a smooth curve of 0.15 mm in a 150 m long sliding window, while for the CLIC project for example, it corresponds to 10 micrometres over a sliding window of 200m in the Beam Delivery System area. Two complementary strategies are being studied to fulfill these requirements: the development and validation of long range alignment systems to propagate precision and accuracy over a few hundreds of metres and short range alignment systems over a few metres. The studies undertaken, with associated test setups and the latest results will be detailed, as well as their application for the alignment of both CLIC and ILC colliders.

WEPME053

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

feedback, kicker, extraction, cavity

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.

THPFI061

Design Process of the Interlock Systems for the Compact Linear Collider

collider, controls, target, hadron

3433

P. Nouvel, M. Jonker, B. Puccio
CERN, Geneva, Switzerland
H. Tap
INPT, Toulouse, France

Interlock systems are a critical part for the machine protection of linear colliders. Their goal is to inhibit the next pulse either on failure of critical equipment and/or on low beam quality evaluation. This paper presents the on-going process to validate design choices for the Compact Linear Collider (CLIC) interlock systems. The design process starts by establishing requirements. In mission-critical system case, they are mainly focused on the dependability. Moreover, the new concept of fast beam quality analysis has been introduced into the CLIC interlock system and will be discussed in this paper. To support the design process, experimentation on this concept has been launched. In addition, a hardware demonstration of the interlock systems has been set-up. It allows validating the design in concordance with the requirements.

THPME043

Prototype Adjustable Permanent Magnet Quadrupoles For CLIC

quadrupole, permanent-magnet, collider, magnet-design

3606

B.J.A. Shepherd, J.A. Clarke
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
A. Bartalesi, M. Modena, M. Struik
CERN, Geneva, Switzerland
N.A. Collomb
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom

The 42km long Drive Beam Decelerator for the Compact Linear Collider (CLIC) requires over 41,000 quadrupole magnets. ASTeC and CERN are investigating the possibility of permanent magnet quadrupoles (PMQs) to reduce running costs and heat load inside the CLIC tunnel. A prototype of a high-strength adjustable PMQ has been built, based on a simple concept using two moving sections each containing a pair of large permanent magnets. The gradient can be adjusted within a range of 15-60 T/m (3-15T integrated gradient). The prototype has undergone extensive magnetic testing at Daresbury Laboratory and CERN, and performs well in line with expectations. A prototype of the low-strength version (0.9-9T) is currently under construction.