IPAC2016 - List of Keywords (scattering)

Paper	Title	Other Keywords	Page
MOPMB006	First Tests of SuperKEKB Luminosity Monitors during 2016 Single Beam Commissioning	luminosity, vacuum, simulation, background	81
	D. El Khechen, P. Bambade, A. Blin, P. Cornebise, D. Jehanno, V. Kubytskyi, Y. Peinaud, C. Rimbault LAL, Orsay, France Y. Funakoshi, Y. Ohnishi, S. Uehara KEK, Ibaraki, Japan
	The SuperKEKB e⁺e⁻ collider aims to reach a very high luminosity of 8 10³⁵ cm^-2s⁻¹, using highly focused ultra-low emittance bunches colliding every 4ns. Fast luminosity monitoring is required for luminosity feedback and optimisation in presence of dynamic imperfections. The aimed relative precision is about 10^-3 in 1ms, which can be in principle achieved thanks to the very large cross-section of the radiative Bhabha process at zero degree scattering angle. Diamond, Cherenkov and scintillator sensors are to be placed just outside the beam pipe, downstream of the interaction point in both rings, at locations with event rates consistent with the aimed precision and small enough backgrounds from single-beam particle losses. The initial configuration installed for the 2016 "phase 1" single beam commissioning will be described, including the sensors, mechanical setup, readout electronics and first stage DAQ. Preliminary measurements and analysis of beam gas Bremsstrahlung loss data collected with the luminosity monitors will be reported and compared with a detailed simulation, for several experimental conditions during the SuperKEKB commissioning.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB006
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MOPMB008	Modeling and Experimental Studies of Beam Halo at ATF2	vacuum, coupling, damping, optics	88
	R.J. Yang, P. Bambade, V. Kubytskyi LAL, Orsay, France A. Faus-Golfe, N. Fuster-Martínez IFIC, Valencia, Spain T. Naito KEK, Ibaraki, Japan
	The Accelerator Test Facility 2 (ATF2) at KEK is a prototype of the final focus system for the next generation of Future Linear Colliders(FCL). It aims to focus the beams to tens of nanometer transverse sizes and to provide stability at the few nm level. Achieving these goals requires modelling, measuring and suppressing of the transverse beam halo before the interaction point (IP). This paper presents a beam tail/halo generator based on realistic model and the investigation of vertical and horizontal beam tail/halo distribution at ATF2.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB008
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MOPOR004	Recent Progress of 1-MW Beam Tuning in the J-PARC 3-GeV RCS	resonance, injection, emittance, power-supply	592
	H. Hotchi, H. Harada, S. Kato, M. Kinsho, K. Okabe, P.K. Saha, Y. Shobuda, F. Tamura, N. Tani, Y. Watanabe, K. Yamamoto, M. Yoshimoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	The J-PARC 3-GeV RCS started 1 MW beam test from October 2014, and successfully achieved a 1 MW beam acceleration in January 2015. Since then, a large fraction of our effort has been focused on reducing and managing beam losses. This paper presents the recent progress of 1 MW beam tuning, especially focusing on our approaches to beam loss issues, such as space-charge induced beam loss and foil scattering beam loss during charge-exchange injection, etc.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOR004
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MOPOW017	Generation of GeV Photons from X-ray Free Electron Laser Oscillators	electron, photon, laser, FEL	751
	R. Hajima JAEA, Ibaraki-ken, Japan M. Fujiwara RCNP, Osaka, Japan
	We propose generation of narrow-bandwidth GeV photons, gamma-rays, via Compton scattering of hard X-ray photons in X-ray free-electron laser oscillators. The gamma-rays have a narrow-bandwidth spectrum with a sharp peak, ~0.1% (FWHM), due to the nature of Compton scattering in relativistic regime. Such gamma-rays will be a unique probe for studying hadron physics. We discuss features of the gamma-ray source, flux, spectrum, polarization, tunability and energy resolution.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW017
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TUPMR009	Analytical Studies of Ion Beam Evolution under Coherent Electron Cooling	ion, electron, synchrotron, simulation	1247
	G. Wang, M. Blaskiewicz, V. Litvinenko BNL, Upton, Long Island, New York, USA V. Litvinenko Stony Brook University, Stony Brook, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. In the presence of coherent electron cooling (CeC), the evolution of the longitudinal profile of a circulating ion bunch can be described by the 1-D Fokker-Planck equation. We show that, in the absence of diffusion, the 1-D equation can be solved analytically for certain dependence of cooling force on the synchrotron amplitude. For more general cases, we solved the 1-D Fokker-Planck equation numerically and the numerical solutions have been used to benchmark our simulation code as well as providing fast estimations of the cooling effects.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR009
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TUPMW002	LHC Luminosity Modeling for RUNII	luminosity, emittance, radiation, proton	1403
	F. Antoniou, G. Arduini, M. Hostettler, M. Lamont, S. Papadopoulou, Y. Papaphilippou, G. Papotti, M. Pojer, B. Salvachua, M. Wyszynski CERN, Geneva, Switzerland
	Funding: Research supported by the High Luminosity LHC project After a long shut-down (LS1), LHC restarted its operation on April 2015 at a record energy of 6.5TeV, achieving soon a good luminosity performance. In this paper, a luminosity model based on the three main components of the LHC luminosity degradation (intrabeam scattering, synchrotron radiation and luminosity burn-off), is compared with data from runII. Based on the observations, other sources of luminosity degradation are discussed and the model is refined. Finally, based on the experience from runI and runII, the model is used for integrated luminosity projections for the HL-LHC beam parameters.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMW002
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TUPMW008	Evolution of the Beam Parameters during Luminosity Production in the Future Circular Hadron Collider	emittance, luminosity, collider, damping	1426
	X. Buffat, D. Schulte CERN, Geneva, Switzerland
	The evolution of the beam parameters during luminosity production in the Future Circular Hadron Collider (FCC-hh) is described based on basic models of the effect of synchrotron radiations, intra-beam scattering, luminosity burn-off and beam-beam limitations, allowing for an estimation of the luminosity performance in different running scenarios. It is shown that a large variations of the beam parameters is expected during a cycle. Potential operational schemes adapting to these variations are considered.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMW008
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TUPMW022	Modelling and Measurements of Bunch Profiles at the LHC Flat Bottom	emittance, lattice, radiation, damping	1477
	S. Papadopoulou, F. Antoniou, J.E. Muller, Y. Papaphilippou, G. Trad CERN, Geneva, Switzerland
	At the LHC flat bottom the interplay between a series of effects (i.e. intrabeam scattering, longitudinal beam manipulations, non-linearities of the machine, etc) can lead to a population of the tails of the beam distributions, which may become non-Gaussian. This paper presents observations of the evolution of particle distributions in the LHC flat bottom. Novel distribution functions are employed to represent the beam profiles, and used as a guideline for generalising emittance growth rate estimations due to IBS. Finally, an attempt is made to benchmark an IBS Monte-Carlo simulation code, able to track 3D particle distributions, with the measured beam profile evolutions.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMW022
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TUPMY006	MICE Step IV Optics without the M1 Coil in SSD	emittance, lattice, solenoid, simulation	1553
	A. Liu Fermilab, Batavia, Illinois, USA
	Funding: Fermi National Accelerator Laboratory The international Muon Ionization Cooling Experiment (MICE) will demonstrate ionization cooling, the only technique that, given the short muon lifetime, can reduce the phase-space volume occupied by a muon beam quickly enough. MICE will demonstrate cooling in two steps. In the first one, Step IV, MICE will study the multiple Coulomb scattering in liquid hydrogen (LH2) and lithium hydride (LiH). A focus coil module will provide focussing on the absorber. The transverse emittance will be measured upstream and downstream of the absorber in two spectrometer solenoids (SS). Magnetic fields generated by two match coils in the SSs allow the beam to be matched into a flat-field regions in which the tracking detectors are installed. An incident in September 2015 rendered matching coil \#1 (M1D) of the downstream spectrometer inoperable. A new Step IV lattice without M1D and its optimization via a Genetic Algorithm (GA) will be described in this paper.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMY006
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TUPMY010	Status of Mice Step IV	emittance, factory, experiment, optics	1562
	P.M. Hanlet IIT, Chicago, Illinois, USA
	Funding: STFC, DOE, NSF, INFN, CHIPP AND MORE Muon beams of low emittance provide the basis for the intense, well characterised neutrino beams of the Neutrino Factory and for lepton-antilepton collisions at energies of up to several TeV at a Muon Collider. The international Muon Ionization Cooling Experiment (MICE) will demonstrate ionization cooling–the technique by which it is proposed to reduce the phase-space volume occupied by the muon beam. MICE is being constructed in a series of Steps. The configuration currently in operation at the Rutherford Appleton Laboratory is optimised for the study the properties of liquid hydrogen and lithium hydride that affect cooling. The plans for data taking in the present configuration will be described together with a summary of the status of preparation of the experimental configuration by which MICE will demonstration the principle of ionization cooling. Submitted by the MICE speakers bureau that will identify later a member of the collaboration to present the contribution
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMY010
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TUPMY012	Hybrid Methods for Simulation of Muon Ionization Cooling Channels	simulation, experiment, emittance, lattice	1568
	J.D. Kunz IIT, Chicago, Illinois, USA M. Berz, K. Makino MSU, East Lansing, Michigan, USA P. Snopok Illinois Institute of Technology, Chicago, Illlinois, USA
	Funding: Work is supported by the U.S. Department of Energy. COSY Infinity is an arbitrary-order beam dynamics simulation and analysis code. It can determine high-order transfer maps of combinations of particle optical elements of arbitrary field configurations. New features are being developed for inclusion in COSY to follow the distribution of charged particles through matter. To study in detail some of the properties of muons passing through material, the transfer map approach alone is not sufficient. The interplay of beam optics and atomic processes must be studied by a hybrid transfer map–Monte Carlo approach in which transfer map methods describe the deterministic behavior of the particles in the accelerator channel, and Monte Carlo methods are used to model the stochastic processes intrinsic to liquid and solid absorbers. The advantage of the new approach is that the vast majority of the dynamics is represented by fast application of the high-order transfer map of an entire element and accumulated stochastic effects. The gains in speed are expected to simplify the optimization of muon cooling channels which are usually very computationally demanding. Progress on the development of the required algorithms is reported.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMY012
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TUPMY013	Progress on Beam-Plasma Effect Simulations in Muon Ionization Cooling Lattices	plasma, simulation, space-charge, emittance	1571
	J.S. Ellison IIT, Chicago, Illinois, USA P. Snopok Illinois Institute of Technology, Chicago, Illlinois, USA
	Funding: Work supported by the U.S. Department of Energy. New computational tools are essential for accurate modeling and simulation of the next generation of muon based accelerator experiments. One of the crucial physics processes specific to muon accelerators that has not yet been implemented in any current simulation code is beam induced plasma effect in liquid, solid, and gaseous absorbers. We report here on the progress of developing the required simulation tools and applying them to study the properties of plasma and its effects on the beam in muon ionization cooling channels.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMY013
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TUPMY030	Measurements of Transmitted Electron Beam Extinction through Si Crystal Membranes	electron, emittance, laser, experiment	1611
	E.A. Nanni, R.K. Li, C. Limborg, X. Shen, S.P. Weathersby SLAC, Menlo Park, California, USA W.S. Graves, R. Kirian, J. Spence, U. Weierstall Arizona State University, Tempe, USA
	A recently proposed method for the generation of relativistic electron beams with nanometer-scale current modulation requires diffracting relativistic electrons from a perfect crystal Si grating, accelerating the diffracted beam and imaging the crystal structure into the temporal dimension via emittance exchange. The relative intensity of the current modulation is limited by the ability to extinguish the transmitted beam via diffraction with a single-crystal Si membrane. In these preliminary experiments we will measure the extinction of the transmitted electron beam at zero scattering angle due to multiple Bragg scattering from a Si membrane with a uniform thickness of 340 nm at 2.35 MeV using the SLAC UED facility. The impact of beam divergence and charge density at the Si target will be quantified. The longevity of the Si membrane will also be investigated by monitoring the diffraction pattern as a function of time to observe the potential onset of damage to the crystal.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMY030
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TUPOW050	Parametric X-rays at FAST	brilliance, electron, photon, detector	1877
	T. Sen Fermilab, Batavia, Illinois, USA
	Funding: Fermilab is operated by Fermi Research Alliance LLC under DOE contract No. DE-AC02CH11359 We discuss the generation of parametric X-rays (PXR) in the photoinjector at the new FAST facility at Fermilab. Detailed calculations of the intensity spectrum, energy and angular widths and spectral brilliance with a diamond crystal are presented. We also report on expected results with PXR generated while the beam is channeling. The low emittance electron beam makes this facility a promising source for creating brilliant X-rays.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW050
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TUPOY024	Wave Particle Cherenkov Interactions Mediated via Novel Materials	simulation, acceleration, electron, operation	1960
	A. Hopper IIAA, Huddersfield, United Kingdom R. Seviour University of Huddersfield, Huddersfield, United Kingdom
	Currently there is an increasing interest in dielectric wall accelerators. These work by slowing the speed of an EM wave to match the velocity of a particle beam, allowing wave-beam interactions, accelerating the beam. However conventional dielectric materials have limited interaction regions, so wave-beam energy transfer is minimal. In this paper we consider Artificial Materials (AMs), as slow wave structures, in the presence of charged particle beams to engineer Inverse-Cherenkov acceleration. AMs are periodic constructs whose properties depend on their subwavelength geometry rather than their material composition, and can be engineered to give an arbitrary dispersion relation. We show that Metamaterials, one example of an AM, can mediate an Inverse-Cherenkov interaction, but break down in high power environments due to high absorption. We consider AMs with low constitutive parameters and show they can exhibit low absorption whilst maintaining the ability to have a user defined dispersion relation, and mediate a wavebeam interaction leading to Inverse-Cherenkov acceleration.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOY024
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WEPMB053	Study of Third Harmonic Cavity for Taiwan Photon Source	cavity, dipole, vacuum, electron	2237
	Z.K. Liu, L.-H. Chang, M.H. Chang, L.J. Chen, PY. Chen, F.-T. Chung, M.-C. Lin, C.H. Lo, C.L. Tsai, M.H. Tsai, Ch. Wang, M.-S. Yeh, T.-C. Yu NSRRC, Hsinchu, Taiwan
	Taiwan Photon Source (TPS) is a modern light source with 3 GeV electron energy and low emittance. The bunch length is about 3 mm at designed beam current of 500 mA and operating gap voltage of 3.2 MV. The short bunch length results in short Touschek lifetime and high parasitic loss of insertion device (ID). Some of the undulators are operated in vacuum at TPS, therefore the head load become an important issue. To install higher harmonic cavity is a solution for improving the Touschek lifetime and the heat load by lengthening the bunch length. The effect of installing 3rd harmonic cavity for TPS is investigated. The expected maximum elongation factor for bunch lengthening, as well as the effect on the Touschek lifetime and heat load of ID are presented in this paper.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMB053
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WEPMW036	MERLIN Cleaning Studies with Advanced Collimator Materials for HL-LHC	collimation, simulation, proton, hadron	2514
	A. Valloni, R. Bruce, A. Mereghetti, E. Quaranta, S. Redaelli CERN, Geneva, Switzerland R.B. Appleby UMAN, Manchester, United Kingdom J. Molson LAL, Orsay, France H. Rafique University of Huddersfield, Huddersfield, United Kingdom
	The challenges of the High-Luminosity upgrade of the Large Hadron Collider require improving the beam collimation system. An intense R&D program has started at CERN to explore novel materials for new collimator jaws to improve robustness and reduce impedance. Particle tracking simulations of collimation efficiency are performed using the code MERLIN which has been extended to include new materials based on composites. After presenting two different implementations of composite materials tested in MERLIN, we present simulation studies with the aim of studying the effect of the advanced collimators on the LHC beam cleaning.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMW036
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WEPMW037	MERLIN Simulations of the LHC Collimation System with 6.5 TeV Beams	collimation, simulation, proton, betatron	2518
	A. Valloni Rome University La Sapienza, Roma, Italy R.B. Appleby, S.C. Tygier UMAN, Manchester, United Kingdom R. Bruce, A. Mereghetti, S. Redaelli CERN, Geneva, Switzerland J. Molson LAL, Orsay, France H. Rafique University of Huddersfield, Huddersfield, United Kingdom
	The accelerator physics code MERLIN has been extended in many areas to make detailed studies of the LHC collima- tion system and calculate loss maps from beam halo losses. Large scale tracking simulations have been produced for the 2015 run configuration at 6.5 TeV. We present results of cleaning inefficiency simulations of the LHC's multi-stage collimation system along with a detailed comparison be- tween MERLIN, SixTrack, and measured beam losses.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMW037
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WEPOR022	Residual Radiation Measurements at J-PARC MR Using the ASTROCAM 7000HS Newly Developed Radioactive Substance Visualization Camera	radiation, controls, electron, site	2719
	N. Ikeda, T. Sugano MHI-MS, Kobe, Japan K. Genba, M. Komeda, Y. Kuroda, D.M. Matsuura MHI, Komaki-si, Japan A. Harayama, T. Takahashi, S. Watanabe ISAS/JAXA, Kanazawa, Japan H. Nakamura, K. Niki, C. Ohmori, M.J. Shirakata KEK, Ibaraki, Japan S. Takeda OIST, Onna-son, Okinawa, Japan
	Mitsubishi Heavy Industries, Ltd. (MHI) released the ASTROCAM 7000HS, a radioactive substance visualization camera. The ASTROCAM 7000HS incorporates the technologies for the gamma-ray detector used for the ASTRO-H satellite, which MHI has been developing under entrustment from and together with scientists at the Institute of Space and Astronautical Science (ISAS) at the Japan Aerospace Exploration Agency (JAXA), and the design was modified for use on land to commercialize the product. MHI and Mitsubishi Heavy Industries Mechatronics Systems, Ltd. (MHI-MS) performed on-site residual radiation measurements at the 50 GeV Main Ring (MR) of the Japan Proton Accelerator Research Complex (J-PARC) under collaboration with the High Energy Accelerator Research Organization (KEK) and the Japan Atomic Energy Agency (JAEA) and succeeded visualization of radiation hot spots of the accelerator components. The outline of the ASTROCAM 7000HS, the measurement principle and the first measurement results at the J-PARC MR are described.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOR022
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WEPOW016	Designing an Ultra Low Emittance Lattices for Iranian Light Source Facility Storage Ring	emittance, lattice, storage-ring, vacuum	2858
	E. Ahmadi, M. Jafarzadeh, J. Rahighi ILSF, Tehran, Iran H. Ghasem IPM, Tehran, Iran S.M. Jazayeri IUST, Narmac, Tehran, Iran
	Electron storage rings are extensively used for high luminosity colliders, damping rings in high-energy physics and synchrotron light sources. To further increase the luminosity at the colliders or brightness of a synchrotron light sources, the beam emittance is being continually pushed downward. In this paper, we investigate the lattice design for the storage ring of Iranian Light Source Facility (ILSF) with an ultra-low emittance, intermediate energy of 3 GeV and circumference of 528 m. We present the design results for a five-band achromat lattice with the natural emittance of 276 pm-rad. The base line is based on 20 straight sections with the length of 7 m.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOW016
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WEPOW039	Preliminary Beam Loss Study of TPS during Beam Commissioning	injection, radiation, photon, EPICS	2926
	C.H. Huang, J. Chen, Y.-S. Cheng, K.T. Hsu, K.H. Hu, D. Lee, C.Y. Liao, C.Y. Wu NSRRC, Hsinchu, Taiwan
	Taiwan photon source (TPS) is a 3rd generation and 3 GeV synchrotron light source in NSRRC. Several types of beam loss monitors (BLMs) such as RadFETs and PIN-diode BLMs are installed in the storage ring to understand the beam loss distribution and mechanism during the injection, decay mode, top-up operation and beam trip. Several RadFETs are also installed around the inserting devices to study the beam loss near the linear scalar. The preliminary beam loss study using RadFETs are PIN-diode BLMs in the storage will be summarized in this report.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOW039
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THPMB035	A Comparative Study of Low Energy Compact Storage Rings for a Thomson Scattering X-ray Source	storage-ring, lattice, emittance, dynamic-aperture	3308
	L. Ovchinnikova, V.I. Shvedunov SINP MSU, Moscow, Russia E.G. Bessonov, M.V. Gorbunkov LPI, Moscow, Russia A.A. Mikhailichenko Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA V.I. Shvedunov LEA MSU, Moscow, Russia
	A low-energy (<50 MeV) compact storage ring is a basic component of an X-ray source with high average flux based on Thomson scattering. Such ring provides electron bunches with ~1 nC charge and repetition rate up to 100 MHz for interaction with intense laser pulses. Such ring should provide a small (tens of microns rms) beam radius at interaction point, must have large dynamic aperture, sufficient space for allocation of different elements, such as laser resonator, RF cavity, fast beam injection/extraction systems, beam pick-ups and correctors. In this report, we present the results of comparative study of four versions of storage ring with different structure of lattices.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMB035
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THPMR020	Bunch Purity Measurements at PETRA III	electron, synchrotron, operation, timing	3434
	J. Keil, H. Ehrlichmann DESY, Hamburg, Germany
	Since 2010 the 6 GeV synchrotron light source PETRA III is in operation. With a horizontal emittance of 1.2 nm*rad, a coupling of typically 1% and a total beam current of 100 mA the machine provides extremely brilliant synchrotron radiation for the users. For time-resolved measurements a filling pattern with 40 equidistant bunches with equal charge is used. To measure parasitic bunches between the main bunches two beamlines are equipped with avalanche photodiodes (APD) and time to digital converters (TDC) electronics. Besides parasitic bunches originating from the pre-accelerators of PETRA III it has been observed that initially empty buckets following the main bunch are populated. Measurements of the effect will be discussed and compared with simulations.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMR020
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THPMY018	Benchmarking and Calibration of Monte Carlo Vacuum Simulations with SynRad and MolFlow+	vacuum, photon, storage-ring, experiment	3695
	J.A. Carter ANL, Argonne, Ilinois, USA
	The APS-Upgrade project is using SynRad and MolFlow+ to evaluate the vacuum system design for the future 6 GeV, 200 mA APS-Upgrade storage ring. The goal of this work is to explore PSD outgassing predictions from the two programs in order to build confidence in pressure calculations for the APS-U storage ring vacuum system. A study is performed on calibrating PSD measurements for aluminum vacuum chambers and then applying them to APS-U vacuum system calculations. The study reveals that a PSD measurement may not reveal a single unique behavior for a vacuum material and that multiple sources should be considered for vacuum calculations.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMY018
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THPOR014	MDI Design in CEPC Partial Double Ring	detector, solenoid, radiation, synchrotron	3802
	S. Bai, J. Gao, Y. Wang, Q.L. Xiu, W.C. Yao, Y. Yue IHEP, Beijing, People's Republic of China
	With the discovery of the higgs boson at around 125GeV, a circular higgs factory design with high luminosity (L ~ 10³⁴ cm^-2 s^-1) is becoming more popular in the accelerator world. The CEPC project in China is one of them. Machine Detector Interface (MDI) is the key research area in electron-positron colliders, especially in CEPC, it is one of the criteria to measure the accelerator and detector design performance. Detector background, collimator and solenoid compensation are the most critical physics problem. Beamstrahlung is the problem which is never gotten into before in the existed electron positron collider of world history. Every kinds of background are bad for detector, and solenoid can make damage to accelerator beam. We will use a Monte Carlo simulation method to calculate and analysis the CEPC detector background and the harm it makes to detector. Anti-solenoid are designed to compensate the strong detector solenoid field of several tesla.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOR014
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THPOR045	Analytical Estimation of ATF Beam Halo Distribution	emittance, vacuum, electron, damping	3888
	D. Wang, J. Gao IHEP, Beijing, People's Republic of China P. Bambade LAL, Orsay, France T. Naito KEK, Ibaraki, Japan
	Funding: Work supported by the National Foundation of Natural Sciences (11505198 and 11575218) Halo distribution is a key topic for background study. This paper has developed an analytical method to give an estimation of ATF beam halo distribution. The equilibrium particle distribution of the beam tail in the ATF damping ring is calculated analytically with different emittance and different vacuum degree. The analytical results agree the measurements very well. This is a general method which can be applied to any electron rings.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOR045
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THPOW023	Intrinsic Emittance Reduction in Transmission Mode Photocathodes	electron, emittance, laser, cathode	3987
	H. Lee, I.V. Bazarov, L. Cultrera Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	High quantum efficiency (QE) and low emittance electron beams provided by multi-alkali photocathodes make them of great interest for next generation high brightness photoinjectors. Spicer's three-step model well describe the photoemission process, however, some photocathode characteristics such as their thickness have not been completely exploited to further improve the brightness of the generated electron beam. In this work, we report on the emittance and QE of a multi-alkali photocathode grown onto glass substrate operated in transmission and reflection modes at different photon energies. We observed a 20% reduction on the intrinsic emittance from the reflection to the transmission mode operation. This observation can be explained by inelastic electron-phonon scattering events experienced by electrons during their transit towards the cathode surface. This scattering will expect the further emittance reduction than the no scattering at the cryo-temperatures.
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THPOW057	Direct High Power Laser Diagnostic Technique on Focused Electron Bunch	laser, electron, experiment, solenoid	4073
	D. Igarashi, A. Endo, K. Sakaue, T. Takahashi, M. Washio RISE, Tokyo, Japan
	In laser produced plasma EUV source, high intensity pulse CO2 laser is essential for plasma generation. To achieve high conversion efﬁciency and stable EUV power, we would like to measure a laser proﬁle in the interaction point. However, there is no way to measure directly the laser profile of such a high intensity laser at the focus point. Therefore, we have been developing laser profiler based on laser Compton scattering(LCS). LCS signal by using focused electron beam shows 1D laser profile. 2D laser profile can be reconstructed by one-dimensional laser profiles from various angles using computer tomography. This method is suitable for high intensity laser, but very small spot size of electron beam is required. To obtain small spot size, we used S-band Cs-Te photocathode RF-Gun and specially designed solenoid lens at Waseda university. We already succeeded in observing minimum beam size of about 20 μm rms and this is adequate to scan the CO2 laser. In this conference, we will report the result of the laser Compton scattering with pulse CO2 laser, the preparatory experiment in measuring a metal wire cross section and the present progresses.
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THPOY034	Simulations of the Beam Loss Distribution at J-PARC Main Ring	proton, simulation, radiation, operation	4175
	B. Yee-Rendón, H. Kuboki, Y. Sato, K. Satou, M.J. Shirakata, T. Toyama KEK, Ibaraki, Japan H. Harada JAEA/J-PARC, Tokai-mura, Japan
	The Japan Proton Accelerator Research Complex (J-PARC) is integrated by a set of high intensity proton accelerators. At this operation level, the monitoring and control of the beam losses and residual radiation are priority for its safe performance and maintenance. At Main Ring (MR), a discrepancy appears between the beam loss signal detected by the monitors and the residual dose measured. To understand this difference and the mechanism that produces these losses, a beam simulation study is implemented using the Strategic Accelerator Design (SAD) and Geometry and Tracking (Geant4) code. The first stage of the survey uses SAD to obtain the location of the losses around the lattice per turn. Then, Geant4 produces the secondary showers in the elements. Finally, we make the extrapolation with the residual radiation and compare with the measurements. The description and results of this work are presented in this paper.
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THPOY059	Synchronization System for Tsinghua Thomson Scattering X-ray Source	laser, controls, LLRF, low-level-rf	4237
	J. Yang, Y.-C. Du, W.-H. Huang, D. Wang, L.X. Yan TUB, Beijing, People's Republic of China J.M. Byrd, L.R. Doolittle, Q. Du, G. Huang, R.B. Wilcox, Y.L. Xu LBNL, Berkeley, California, USA
	Tsinghua Thomson scattering X-ray Source (TTX) generates X-ray based on inverse thomson scattering method. The synchronization system for TTX includes reference distribution, normal conducting cavity Low Level RF control and Laser-RF synchronization. In collaboration with LBNL, we're working on a prototype synchronization system for TTX. Some test result based on Tsinghua Thomson scattering X-ray Source were obtained. In this paper we will show the synchronization system design and preliminary test result.
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Paper

Title

Other Keywords

Page

MOPMB006

First Tests of SuperKEKB Luminosity Monitors during 2016 Single Beam Commissioning

luminosity, vacuum, simulation, background

81

D. El Khechen, P. Bambade, A. Blin, P. Cornebise, D. Jehanno, V. Kubytskyi, Y. Peinaud, C. Rimbault
LAL, Orsay, France
Y. Funakoshi, Y. Ohnishi, S. Uehara
KEK, Ibaraki, Japan

The SuperKEKB e⁺e⁻ collider aims to reach a very high luminosity of 8 10³⁵ cm^-2s⁻¹, using highly focused ultra-low emittance bunches colliding every 4ns. Fast luminosity monitoring is required for luminosity feedback and optimisation in presence of dynamic imperfections. The aimed relative precision is about 10^-3 in 1ms, which can be in principle achieved thanks to the very large cross-section of the radiative Bhabha process at zero degree scattering angle. Diamond, Cherenkov and scintillator sensors are to be placed just outside the beam pipe, downstream of the interaction point in both rings, at locations with event rates consistent with the aimed precision and small enough backgrounds from single-beam particle losses. The initial configuration installed for the 2016 "phase 1" single beam commissioning will be described, including the sensors, mechanical setup, readout electronics and first stage DAQ. Preliminary measurements and analysis of beam gas Bremsstrahlung loss data collected with the luminosity monitors will be reported and compared with a detailed simulation, for several experimental conditions during the SuperKEKB commissioning.

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MOPMB008

Modeling and Experimental Studies of Beam Halo at ATF2

vacuum, coupling, damping, optics

88

R.J. Yang, P. Bambade, V. Kubytskyi
LAL, Orsay, France
A. Faus-Golfe, N. Fuster-Martínez
IFIC, Valencia, Spain
T. Naito
KEK, Ibaraki, Japan

The Accelerator Test Facility 2 (ATF2) at KEK is a prototype of the final focus system for the next generation of Future Linear Colliders(FCL). It aims to focus the beams to tens of nanometer transverse sizes and to provide stability at the few nm level. Achieving these goals requires modelling, measuring and suppressing of the transverse beam halo before the interaction point (IP). This paper presents a beam tail/halo generator based on realistic model and the investigation of vertical and horizontal beam tail/halo distribution at ATF2.

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MOPOR004

Recent Progress of 1-MW Beam Tuning in the J-PARC 3-GeV RCS

resonance, injection, emittance, power-supply

592

H. Hotchi, H. Harada, S. Kato, M. Kinsho, K. Okabe, P.K. Saha, Y. Shobuda, F. Tamura, N. Tani, Y. Watanabe, K. Yamamoto, M. Yoshimoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

The J-PARC 3-GeV RCS started 1 MW beam test from October 2014, and successfully achieved a 1 MW beam acceleration in January 2015. Since then, a large fraction of our effort has been focused on reducing and managing beam losses. This paper presents the recent progress of 1 MW beam tuning, especially focusing on our approaches to beam loss issues, such as space-charge induced beam loss and foil scattering beam loss during charge-exchange injection, etc.

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MOPOW017

Generation of GeV Photons from X-ray Free Electron Laser Oscillators

electron, photon, laser, FEL

751

R. Hajima
JAEA, Ibaraki-ken, Japan
M. Fujiwara
RCNP, Osaka, Japan

We propose generation of narrow-bandwidth GeV photons, gamma-rays, via Compton scattering of hard X-ray photons in X-ray free-electron laser oscillators. The gamma-rays have a narrow-bandwidth spectrum with a sharp peak, ~0.1% (FWHM), due to the nature of Compton scattering in relativistic regime. Such gamma-rays will be a unique probe for studying hadron physics. We discuss features of the gamma-ray source, flux, spectrum, polarization, tunability and energy resolution.

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TUPMR009

Analytical Studies of Ion Beam Evolution under Coherent Electron Cooling

ion, electron, synchrotron, simulation

1247

G. Wang, M. Blaskiewicz, V. Litvinenko
BNL, Upton, Long Island, New York, USA
V. Litvinenko
Stony Brook University, Stony Brook, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
In the presence of coherent electron cooling (CeC), the evolution of the longitudinal profile of a circulating ion bunch can be described by the 1-D Fokker-Planck equation. We show that, in the absence of diffusion, the 1-D equation can be solved analytically for certain dependence of cooling force on the synchrotron amplitude. For more general cases, we solved the 1-D Fokker-Planck equation numerically and the numerical solutions have been used to benchmark our simulation code as well as providing fast estimations of the cooling effects.

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TUPMW002

LHC Luminosity Modeling for RUNII

luminosity, emittance, radiation, proton

1403

F. Antoniou, G. Arduini, M. Hostettler, M. Lamont, S. Papadopoulou, Y. Papaphilippou, G. Papotti, M. Pojer, B. Salvachua, M. Wyszynski
CERN, Geneva, Switzerland

Funding: Research supported by the High Luminosity LHC project
After a long shut-down (LS1), LHC restarted its operation on April 2015 at a record energy of 6.5TeV, achieving soon a good luminosity performance. In this paper, a luminosity model based on the three main components of the LHC luminosity degradation (intrabeam scattering, synchrotron radiation and luminosity burn-off), is compared with data from runII. Based on the observations, other sources of luminosity degradation are discussed and the model is refined. Finally, based on the experience from runI and runII, the model is used for integrated luminosity projections for the HL-LHC beam parameters.

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TUPMW008

Evolution of the Beam Parameters during Luminosity Production in the Future Circular Hadron Collider

emittance, luminosity, collider, damping

1426

X. Buffat, D. Schulte
CERN, Geneva, Switzerland

The evolution of the beam parameters during luminosity production in the Future Circular Hadron Collider (FCC-hh) is described based on basic models of the effect of synchrotron radiations, intra-beam scattering, luminosity burn-off and beam-beam limitations, allowing for an estimation of the luminosity performance in different running scenarios. It is shown that a large variations of the beam parameters is expected during a cycle. Potential operational schemes adapting to these variations are considered.

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TUPMW022

Modelling and Measurements of Bunch Profiles at the LHC Flat Bottom

emittance, lattice, radiation, damping

1477

S. Papadopoulou, F. Antoniou, J.E. Muller, Y. Papaphilippou, G. Trad
CERN, Geneva, Switzerland

At the LHC flat bottom the interplay between a series of effects (i.e. intrabeam scattering, longitudinal beam manipulations, non-linearities of the machine, etc) can lead to a population of the tails of the beam distributions, which may become non-Gaussian. This paper presents observations of the evolution of particle distributions in the LHC flat bottom. Novel distribution functions are employed to represent the beam profiles, and used as a guideline for generalising emittance growth rate estimations due to IBS. Finally, an attempt is made to benchmark an IBS Monte-Carlo simulation code, able to track 3D particle distributions, with the measured beam profile evolutions.

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TUPMY006

MICE Step IV Optics without the M1 Coil in SSD

emittance, lattice, solenoid, simulation

1553

A. Liu
Fermilab, Batavia, Illinois, USA

Funding: Fermi National Accelerator Laboratory
The international Muon Ionization Cooling Experiment (MICE) will demonstrate ionization cooling, the only technique that, given the short muon lifetime, can reduce the phase-space volume occupied by a muon beam quickly enough. MICE will demonstrate cooling in two steps. In the first one, Step IV, MICE will study the multiple Coulomb scattering in liquid hydrogen (LH2) and lithium hydride (LiH). A focus coil module will provide focussing on the absorber. The transverse emittance will be measured upstream and downstream of the absorber in two spectrometer solenoids (SS). Magnetic fields generated by two match coils in the SSs allow the beam to be matched into a flat-field regions in which the tracking detectors are installed. An incident in September 2015 rendered matching coil \#1 (M1D) of the downstream spectrometer inoperable. A new Step IV lattice without M1D and its optimization via a Genetic Algorithm (GA) will be described in this paper.

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TUPMY010

Status of Mice Step IV

emittance, factory, experiment, optics

1562

P.M. Hanlet
IIT, Chicago, Illinois, USA

Funding: STFC, DOE, NSF, INFN, CHIPP AND MORE
Muon beams of low emittance provide the basis for the intense, well characterised neutrino beams of the Neutrino Factory and for lepton-antilepton collisions at energies of up to several TeV at a Muon Collider. The international Muon Ionization Cooling Experiment (MICE) will demonstrate ionization cooling–the technique by which it is proposed to reduce the phase-space volume occupied by the muon beam. MICE is being constructed in a series of Steps. The configuration currently in operation at the Rutherford Appleton Laboratory is optimised for the study the properties of liquid hydrogen and lithium hydride that affect cooling. The plans for data taking in the present configuration will be described together with a summary of the status of preparation of the experimental configuration by which MICE will demonstration the principle of ionization cooling.
Submitted by the MICE speakers bureau that will identify later a member of the collaboration to present the contribution

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TUPMY012

Hybrid Methods for Simulation of Muon Ionization Cooling Channels

simulation, experiment, emittance, lattice

1568

J.D. Kunz
IIT, Chicago, Illinois, USA
M. Berz, K. Makino
MSU, East Lansing, Michigan, USA
P. Snopok
Illinois Institute of Technology, Chicago, Illlinois, USA

Funding: Work is supported by the U.S. Department of Energy.
COSY Infinity is an arbitrary-order beam dynamics simulation and analysis code. It can determine high-order transfer maps of combinations of particle optical elements of arbitrary field configurations. New features are being developed for inclusion in COSY to follow the distribution of charged particles through matter. To study in detail some of the properties of muons passing through material, the transfer map approach alone is not sufficient. The interplay of beam optics and atomic processes must be studied by a hybrid transfer map–Monte Carlo approach in which transfer map methods describe the deterministic behavior of the particles in the accelerator channel, and Monte Carlo methods are used to model the stochastic processes intrinsic to liquid and solid absorbers. The advantage of the new approach is that the vast majority of the dynamics is represented by fast application of the high-order transfer map of an entire element and accumulated stochastic effects. The gains in speed are expected to simplify the optimization of muon cooling channels which are usually very computationally demanding. Progress on the development of the required algorithms is reported.

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TUPMY013

Progress on Beam-Plasma Effect Simulations in Muon Ionization Cooling Lattices

plasma, simulation, space-charge, emittance

1571

J.S. Ellison
IIT, Chicago, Illinois, USA
P. Snopok
Illinois Institute of Technology, Chicago, Illlinois, USA

Funding: Work supported by the U.S. Department of Energy.
New computational tools are essential for accurate modeling and simulation of the next generation of muon based accelerator experiments. One of the crucial physics processes specific to muon accelerators that has not yet been implemented in any current simulation code is beam induced plasma effect in liquid, solid, and gaseous absorbers. We report here on the progress of developing the required simulation tools and applying them to study the properties of plasma and its effects on the beam in muon ionization cooling channels.

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TUPMY030

Measurements of Transmitted Electron Beam Extinction through Si Crystal Membranes

electron, emittance, laser, experiment

1611

E.A. Nanni, R.K. Li, C. Limborg, X. Shen, S.P. Weathersby
SLAC, Menlo Park, California, USA
W.S. Graves, R. Kirian, J. Spence, U. Weierstall
Arizona State University, Tempe, USA

A recently proposed method for the generation of relativistic electron beams with nanometer-scale current modulation requires diffracting relativistic electrons from a perfect crystal Si grating, accelerating the diffracted beam and imaging the crystal structure into the temporal dimension via emittance exchange. The relative intensity of the current modulation is limited by the ability to extinguish the transmitted beam via diffraction with a single-crystal Si membrane. In these preliminary experiments we will measure the extinction of the transmitted electron beam at zero scattering angle due to multiple Bragg scattering from a Si membrane with a uniform thickness of 340 nm at 2.35 MeV using the SLAC UED facility. The impact of beam divergence and charge density at the Si target will be quantified. The longevity of the Si membrane will also be investigated by monitoring the diffraction pattern as a function of time to observe the potential onset of damage to the crystal.

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TUPOW050

Parametric X-rays at FAST

brilliance, electron, photon, detector

1877

T. Sen
Fermilab, Batavia, Illinois, USA

Funding: Fermilab is operated by Fermi Research Alliance LLC under DOE contract No. DE-AC02CH11359
We discuss the generation of parametric X-rays (PXR) in the photoinjector at the new FAST facility at Fermilab. Detailed calculations of the intensity spectrum, energy and angular widths and spectral brilliance with a diamond crystal are presented. We also report on expected results with PXR generated while the beam is channeling. The low emittance electron beam makes this facility a promising source for creating brilliant X-rays.

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TUPOY024

Wave Particle Cherenkov Interactions Mediated via Novel Materials

simulation, acceleration, electron, operation

1960

A. Hopper
IIAA, Huddersfield, United Kingdom
R. Seviour
University of Huddersfield, Huddersfield, United Kingdom

Currently there is an increasing interest in dielectric wall accelerators. These work by slowing the speed of an EM wave to match the velocity of a particle beam, allowing wave-beam interactions, accelerating the beam. However conventional dielectric materials have limited interaction regions, so wave-beam energy transfer is minimal. In this paper we consider Artificial Materials (AMs), as slow wave structures, in the presence of charged particle beams to engineer Inverse-Cherenkov acceleration. AMs are periodic constructs whose properties depend on their subwavelength geometry rather than their material composition, and can be engineered to give an arbitrary dispersion relation. We show that Metamaterials, one example of an AM, can mediate an Inverse-Cherenkov interaction, but break down in high power environments due to high absorption. We consider AMs with low constitutive parameters and show they can exhibit low absorption whilst maintaining the ability to have a user defined dispersion relation, and mediate a wavebeam interaction leading to Inverse-Cherenkov acceleration.

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WEPMB053

Study of Third Harmonic Cavity for Taiwan Photon Source

cavity, dipole, vacuum, electron

2237

Z.K. Liu, L.-H. Chang, M.H. Chang, L.J. Chen, PY. Chen, F.-T. Chung, M.-C. Lin, C.H. Lo, C.L. Tsai, M.H. Tsai, Ch. Wang, M.-S. Yeh, T.-C. Yu
NSRRC, Hsinchu, Taiwan

Taiwan Photon Source (TPS) is a modern light source with 3 GeV electron energy and low emittance. The bunch length is about 3 mm at designed beam current of 500 mA and operating gap voltage of 3.2 MV. The short bunch length results in short Touschek lifetime and high parasitic loss of insertion device (ID). Some of the undulators are operated in vacuum at TPS, therefore the head load become an important issue. To install higher harmonic cavity is a solution for improving the Touschek lifetime and the heat load by lengthening the bunch length. The effect of installing 3rd harmonic cavity for TPS is investigated. The expected maximum elongation factor for bunch lengthening, as well as the effect on the Touschek lifetime and heat load of ID are presented in this paper.

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WEPMW036

MERLIN Cleaning Studies with Advanced Collimator Materials for HL-LHC

collimation, simulation, proton, hadron

2514

A. Valloni, R. Bruce, A. Mereghetti, E. Quaranta, S. Redaelli
CERN, Geneva, Switzerland
R.B. Appleby
UMAN, Manchester, United Kingdom
J. Molson
LAL, Orsay, France
H. Rafique
University of Huddersfield, Huddersfield, United Kingdom

The challenges of the High-Luminosity upgrade of the Large Hadron Collider require improving the beam collimation system. An intense R&D program has started at CERN to explore novel materials for new collimator jaws to improve robustness and reduce impedance. Particle tracking simulations of collimation efficiency are performed using the code MERLIN which has been extended to include new materials based on composites. After presenting two different implementations of composite materials tested in MERLIN, we present simulation studies with the aim of studying the effect of the advanced collimators on the LHC beam cleaning.

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WEPMW037

MERLIN Simulations of the LHC Collimation System with 6.5 TeV Beams

collimation, simulation, proton, betatron

2518

A. Valloni
Rome University La Sapienza, Roma, Italy
R.B. Appleby, S.C. Tygier
UMAN, Manchester, United Kingdom
R. Bruce, A. Mereghetti, S. Redaelli
CERN, Geneva, Switzerland
J. Molson
LAL, Orsay, France
H. Rafique
University of Huddersfield, Huddersfield, United Kingdom

The accelerator physics code MERLIN has been extended in many areas to make detailed studies of the LHC collima- tion system and calculate loss maps from beam halo losses. Large scale tracking simulations have been produced for the 2015 run configuration at 6.5 TeV. We present results of cleaning inefficiency simulations of the LHC's multi-stage collimation system along with a detailed comparison be- tween MERLIN, SixTrack, and measured beam losses.

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WEPOR022

Residual Radiation Measurements at J-PARC MR Using the ASTROCAM 7000HS Newly Developed Radioactive Substance Visualization Camera

radiation, controls, electron, site

2719

N. Ikeda, T. Sugano
MHI-MS, Kobe, Japan
K. Genba, M. Komeda, Y. Kuroda, D.M. Matsuura
MHI, Komaki-si, Japan
A. Harayama, T. Takahashi, S. Watanabe
ISAS/JAXA, Kanazawa, Japan
H. Nakamura, K. Niki, C. Ohmori, M.J. Shirakata
KEK, Ibaraki, Japan
S. Takeda
OIST, Onna-son, Okinawa, Japan

Mitsubishi Heavy Industries, Ltd. (MHI) released the ASTROCAM 7000HS, a radioactive substance visualization camera. The ASTROCAM 7000HS incorporates the technologies for the gamma-ray detector used for the ASTRO-H satellite, which MHI has been developing under entrustment from and together with scientists at the Institute of Space and Astronautical Science (ISAS) at the Japan Aerospace Exploration Agency (JAXA), and the design was modified for use on land to commercialize the product. MHI and Mitsubishi Heavy Industries Mechatronics Systems, Ltd. (MHI-MS) performed on-site residual radiation measurements at the 50 GeV Main Ring (MR) of the Japan Proton Accelerator Research Complex (J-PARC) under collaboration with the High Energy Accelerator Research Organization (KEK) and the Japan Atomic Energy Agency (JAEA) and succeeded visualization of radiation hot spots of the accelerator components. The outline of the ASTROCAM 7000HS, the measurement principle and the first measurement results at the J-PARC MR are described.

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WEPOW016

Designing an Ultra Low Emittance Lattices for Iranian Light Source Facility Storage Ring

emittance, lattice, storage-ring, vacuum

2858

E. Ahmadi, M. Jafarzadeh, J. Rahighi
ILSF, Tehran, Iran
H. Ghasem
IPM, Tehran, Iran
S.M. Jazayeri
IUST, Narmac, Tehran, Iran

Electron storage rings are extensively used for high luminosity colliders, damping rings in high-energy physics and synchrotron light sources. To further increase the luminosity at the colliders or brightness of a synchrotron light sources, the beam emittance is being continually pushed downward. In this paper, we investigate the lattice design for the storage ring of Iranian Light Source Facility (ILSF) with an ultra-low emittance, intermediate energy of 3 GeV and circumference of 528 m. We present the design results for a five-band achromat lattice with the natural emittance of 276 pm-rad. The base line is based on 20 straight sections with the length of 7 m.

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WEPOW039

Preliminary Beam Loss Study of TPS during Beam Commissioning

injection, radiation, photon, EPICS

2926

C.H. Huang, J. Chen, Y.-S. Cheng, K.T. Hsu, K.H. Hu, D. Lee, C.Y. Liao, C.Y. Wu
NSRRC, Hsinchu, Taiwan

Taiwan photon source (TPS) is a 3rd generation and 3 GeV synchrotron light source in NSRRC. Several types of beam loss monitors (BLMs) such as RadFETs and PIN-diode BLMs are installed in the storage ring to understand the beam loss distribution and mechanism during the injection, decay mode, top-up operation and beam trip. Several RadFETs are also installed around the inserting devices to study the beam loss near the linear scalar. The preliminary beam loss study using RadFETs are PIN-diode BLMs in the storage will be summarized in this report.

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOW039

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THPMB035

A Comparative Study of Low Energy Compact Storage Rings for a Thomson Scattering X-ray Source

storage-ring, lattice, emittance, dynamic-aperture

3308

L. Ovchinnikova, V.I. Shvedunov
SINP MSU, Moscow, Russia
E.G. Bessonov, M.V. Gorbunkov
LPI, Moscow, Russia
A.A. Mikhailichenko
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
V.I. Shvedunov
LEA MSU, Moscow, Russia

A low-energy (<50 MeV) compact storage ring is a basic component of an X-ray source with high average flux based on Thomson scattering. Such ring provides electron bunches with ~1 nC charge and repetition rate up to 100 MHz for interaction with intense laser pulses. Such ring should provide a small (tens of microns rms) beam radius at interaction point, must have large dynamic aperture, sufficient space for allocation of different elements, such as laser resonator, RF cavity, fast beam injection/extraction systems, beam pick-ups and correctors. In this report, we present the results of comparative study of four versions of storage ring with different structure of lattices.

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMB035

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THPMR020

Bunch Purity Measurements at PETRA III

electron, synchrotron, operation, timing

3434

J. Keil, H. Ehrlichmann
DESY, Hamburg, Germany

Since 2010 the 6 GeV synchrotron light source PETRA III is in operation. With a horizontal emittance of 1.2 nm*rad, a coupling of typically 1% and a total beam current of 100 mA the machine provides extremely brilliant synchrotron radiation for the users. For time-resolved measurements a filling pattern with 40 equidistant bunches with equal charge is used. To measure parasitic bunches between the main bunches two beamlines are equipped with avalanche photodiodes (APD) and time to digital converters (TDC) electronics. Besides parasitic bunches originating from the pre-accelerators of PETRA III it has been observed that initially empty buckets following the main bunch are populated. Measurements of the effect will be discussed and compared with simulations.

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMR020

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THPMY018

Benchmarking and Calibration of Monte Carlo Vacuum Simulations with SynRad and MolFlow+

vacuum, photon, storage-ring, experiment

3695

J.A. Carter
ANL, Argonne, Ilinois, USA

The APS-Upgrade project is using SynRad and MolFlow+ to evaluate the vacuum system design for the future 6 GeV, 200 mA APS-Upgrade storage ring. The goal of this work is to explore PSD outgassing predictions from the two programs in order to build confidence in pressure calculations for the APS-U storage ring vacuum system. A study is performed on calibrating PSD measurements for aluminum vacuum chambers and then applying them to APS-U vacuum system calculations. The study reveals that a PSD measurement may not reveal a single unique behavior for a vacuum material and that multiple sources should be considered for vacuum calculations.

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMY018

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THPOR014

MDI Design in CEPC Partial Double Ring

detector, solenoid, radiation, synchrotron

3802

S. Bai, J. Gao, Y. Wang, Q.L. Xiu, W.C. Yao, Y. Yue
IHEP, Beijing, People's Republic of China

With the discovery of the higgs boson at around 125GeV, a circular higgs factory design with high luminosity (L ~ 10³⁴ cm^-2 s^-1) is becoming more popular in the accelerator world. The CEPC project in China is one of them. Machine Detector Interface (MDI) is the key research area in electron-positron colliders, especially in CEPC, it is one of the criteria to measure the accelerator and detector design performance. Detector background, collimator and solenoid compensation are the most critical physics problem. Beamstrahlung is the problem which is never gotten into before in the existed electron positron collider of world history. Every kinds of background are bad for detector, and solenoid can make damage to accelerator beam. We will use a Monte Carlo simulation method to calculate and analysis the CEPC detector background and the harm it makes to detector. Anti-solenoid are designed to compensate the strong detector solenoid field of several tesla.

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOR014

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THPOR045

Analytical Estimation of ATF Beam Halo Distribution

emittance, vacuum, electron, damping

3888

D. Wang, J. Gao
IHEP, Beijing, People's Republic of China
P. Bambade
LAL, Orsay, France
T. Naito
KEK, Ibaraki, Japan

Funding: Work supported by the National Foundation of Natural Sciences (11505198 and 11575218)
Halo distribution is a key topic for background study. This paper has developed an analytical method to give an estimation of ATF beam halo distribution. The equilibrium particle distribution of the beam tail in the ATF damping ring is calculated analytically with different emittance and different vacuum degree. The analytical results agree the measurements very well. This is a general method which can be applied to any electron rings.

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOR045

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THPOW023

Intrinsic Emittance Reduction in Transmission Mode Photocathodes

electron, emittance, laser, cathode

3987

H. Lee, I.V. Bazarov, L. Cultrera
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

High quantum efficiency (QE) and low emittance electron beams provided by multi-alkali photocathodes make them of great interest for next generation high brightness photoinjectors. Spicer's three-step model well describe the photoemission process, however, some photocathode characteristics such as their thickness have not been completely exploited to further improve the brightness of the generated electron beam. In this work, we report on the emittance and QE of a multi-alkali photocathode grown onto glass substrate operated in transmission and reflection modes at different photon energies. We observed a 20% reduction on the intrinsic emittance from the reflection to the transmission mode operation. This observation can be explained by inelastic electron-phonon scattering events experienced by electrons during their transit towards the cathode surface. This scattering will expect the further emittance reduction than the no scattering at the cryo-temperatures.

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW023

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THPOW057

Direct High Power Laser Diagnostic Technique on Focused Electron Bunch

laser, electron, experiment, solenoid

4073

D. Igarashi, A. Endo, K. Sakaue, T. Takahashi, M. Washio
RISE, Tokyo, Japan

In laser produced plasma EUV source, high intensity pulse CO2 laser is essential for plasma generation. To achieve high conversion efﬁciency and stable EUV power, we would like to measure a laser proﬁle in the interaction point. However, there is no way to measure directly the laser profile of such a high intensity laser at the focus point. Therefore, we have been developing laser profiler based on laser Compton scattering(LCS). LCS signal by using focused electron beam shows 1D laser profile. 2D laser profile can be reconstructed by one-dimensional laser profiles from various angles using computer tomography. This method is suitable for high intensity laser, but very small spot size of electron beam is required. To obtain small spot size, we used S-band Cs-Te photocathode RF-Gun and specially designed solenoid lens at Waseda university. We already succeeded in observing minimum beam size of about 20 μm rms and this is adequate to scan the CO2 laser. In this conference, we will report the result of the laser Compton scattering with pulse CO2 laser, the preparatory experiment in measuring a metal wire cross section and the present progresses.

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW057

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THPOY034

Simulations of the Beam Loss Distribution at J-PARC Main Ring

proton, simulation, radiation, operation

4175

B. Yee-Rendón, H. Kuboki, Y. Sato, K. Satou, M.J. Shirakata, T. Toyama
KEK, Ibaraki, Japan
H. Harada
JAEA/J-PARC, Tokai-mura, Japan

The Japan Proton Accelerator Research Complex (J-PARC) is integrated by a set of high intensity proton accelerators. At this operation level, the monitoring and control of the beam losses and residual radiation are priority for its safe performance and maintenance. At Main Ring (MR), a discrepancy appears between the beam loss signal detected by the monitors and the residual dose measured. To understand this difference and the mechanism that produces these losses, a beam simulation study is implemented using the Strategic Accelerator Design (SAD) and Geometry and Tracking (Geant4) code. The first stage of the survey uses SAD to obtain the location of the losses around the lattice per turn. Then, Geant4 produces the secondary showers in the elements. Finally, we make the extrapolation with the residual radiation and compare with the measurements. The description and results of this work are presented in this paper.

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOY034

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THPOY059

Synchronization System for Tsinghua Thomson Scattering X-ray Source

laser, controls, LLRF, low-level-rf

4237

J. Yang, Y.-C. Du, W.-H. Huang, D. Wang, L.X. Yan
TUB, Beijing, People's Republic of China
J.M. Byrd, L.R. Doolittle, Q. Du, G. Huang, R.B. Wilcox, Y.L. Xu
LBNL, Berkeley, California, USA

Tsinghua Thomson scattering X-ray Source (TTX) generates X-ray based on inverse thomson scattering method. The synchronization system for TTX includes reference distribution, normal conducting cavity Low Level RF control and Laser-RF synchronization. In collaboration with LBNL, we're working on a prototype synchronization system for TTX. Some test result based on Tsinghua Thomson scattering X-ray Source were obtained. In this paper we will show the synchronization system design and preliminary test result.

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOY059

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