IPAC2015 - List of Keywords (background)

Paper	Title	Other Keywords	Page
MOPJE078	Beam Delivery Simulation - Recent Developments and Optimization	simulation, collider, toolkit, linear-collider	499
	J. Snuverink, S.T. Boogert, H. Garcia Morales, S.M. Gibson, R. Kwee-Hinzmann, L.J. Nevay JAI, Egham, Surrey, United Kingdom L.C. Deacon UCL, London, United Kingdom
	Funding: Research supported by FP7 HiLumi LHC - grant agreement 284404 and by the STFC via the JAI3 grant Beam Delivery Simulation (BDSIM) is a particle tracking code that simulates the passage of particles through both the magnetic accelerator lattice as well as their interaction with the material of the accelerator itself. The Geant4 toolkit is used to give a full range of physics processes needed to simulate both the interaction of primary particles and the production and subsequent propagation of secondaries. BDSIM has already been used to simulate linear accelerators such as the International Linear Collider (ILC) and the Compact Linear Collider (CLIC), but it has recently been adapted to simulate circular accelerators as well, producing loss maps for the Large Hadron Collider (LHC). In this paper the most recent developments, which extend BDSIM's functionality as well as improve its efficiency are presented. Improvement and refactorisation of the tracking algorithms are presented alongside improved automatic geometry construction for increased particle tracking speed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE078
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPHA027	Transverse Emittance Measurement at REGAE	emittance, electron, detector, solenoid	837
	M. Hachmann, K. Flöttmann DESY, Hamburg, Germany
	The linear accelerator REGAE at DESY produces short and low charged electron bunches, on the one hand to resolve the excitation transitions of atoms temporally by pump probe electron diffraction experiments and on the other hand to investigate principal mechanisms of laser plasma acceleration. For both cases a high quality electron beam is required which can be identified with a small beam emittance. A standard magnet scan is used for the emittance measurement which is in case of a low charged bunch most sensitive to the beam size determination (2nd central moment of a distribution). Therefore the diagnostic and a routine to calculate proper central moments of an arbitrary distribution will be introduced and discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPHA027
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPWI014	Design and Development for the Next Generation X-ray Beam Position Monitor System at the APS	undulator, electron, photon, coupling	1175
	B.X. Yang, G. Decker, Y. Jaski, S.-H. Lee, M. Ramanathan, N. Sereno, F. Westferro ANL, Argonne, Ilinois, USA
	Funding: Work performed at Argonne National Laboratory, operated by UChicago Argonne, LLC, for the U.S. Department of Energy under contract DE-AC02-06CH11357. The proposed Advanced Photon Source (APS) Upgrade will bring storage-ring beam sizes down to several micrometers and require x-ray beam directional stability in 100 nrad range for undulator power exceeding 16 kW. The next generation x-ray beam position monitors (XBPMs) are designed to meet these requirements. We present first commissioning data on the recently installed grazing-incidence insertion device x-ray beam position monitor (GRID-XBPM) based on Cu K-edge x-ray fluorescence from limiting absorbers of the front end for two inline undulators. It demonstrated a 50-fold improvement for signal-to-background ratio over existing photoemission-based XBPMs. Techniques for calibrating the XBPMs will be discussed. We will also present a new XBPM design based Compton scattering from diamond blades. This XBPM is designed for less powerful undulators such as the APS canted-undulator beamlines where each undulator generates < 10 kW of beam power. We will discuss the thermal design of the blade, the optics design of the detector assembly, and computer simulations of expected response to the x-ray beam. Test data of the prototype may be presented if available.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWI014
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPJE032	Updates of the PAL-XFEL Undulator Program	undulator, FEL, electron, controls	1675
	D.E. Kim, M.-H. Cho, Y.-G. Jung, H.-S. Kang, I.S. Ko, H.-G. Lee, S.B. Lee, W.W. Lee, B.G. Oh, K.-H. Park, H.S. Suh PAL, Pohang, Kyungbuk, Republic of Korea S. Karabekyan, J. Pflüger XFEL. EU, Hamburg, Germany
	Pohang Accelerator Laboratory (PAL) is developing a 0.1 nm SASE based FEL based on 10 GeV S-band linear accelerator named PAL-XFEL. At the first stage, PAL-XFEL needs two undulator lines for photon source. The hard X-ray undulator line requires 18 units of 5 m long hybrid-type conventional planar undulator and soft X-ray line requires 6 units of 5 m long hybrid type planar undulator with additional few EPUs for final polarization control. PAL is developing undulator magnetic structure based on EU-XFEL concepts. The key parameters are min pole gap of 8.3 mm, with period length 26 mm (HXU), 35 mm (SXU), and 5.0 m magnetic length. . In this report, the prototyping, and the development of pole tuning procedure, the impact of the background field error, and the effects of the girder bending on the optical phase error will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPJE032
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTY016	Study of Background and MDI Design for CEPC	detector, scattering, photon, simulation	2028
	Y. Yue, Q. Qin IHEP, Beijing, People's Republic of China
	CEPC is a project designed to obtain a large number of Higgs events by keeping e⁺e⁻ collisions at the center-of-mass energy of 240 GeV and deliver peak luminosity above 10³⁴ cm^-2 s^-1 for each interaction point. The super high energy and the pretty high luminosity will bring some special background problems, which will exert difficulty on the MDI design and the detectors protection. In this article, I will show the simulation result of the main background sources at CEPC and give some suggestions on the MDI design and detectors protection.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY016
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTY019	Realistic Beam Halo Model study in the Extraction Line of ATF2	simulation, optics, electron, diagnostics	2038
	N. Fuster-Martínez, A. Faus-Golfe IFIC, Valencia, Spain P. Bambade, S. Liu, S. Wallon LAL, Orsay, France K. Kubo, T. Okugi, T. Tauchi, N. Terunuma KEK, Ibaraki, Japan E. Marín, G.R. White SLAC, Menlo Park, California, USA
	Funding: Work supported by IDC-20101074, FPA2013-47883-C2-1-P and ANR-11-IDEX-0003-02 The understanding and control of the transverse beam halo distributions is an important issue to reduce sources of background noise in Future Linear Colliders (FLC) and specifically at ATF2. A realistic model of the beam halo in the old extraction line of the ATF damping ring was obtained in 2005, based on wire scanner measurements. Recently, new measurements were done in the new extraction line of ATF2, using both wire scanners, in 2013, and Optical Transition Radiation monitors (OTR), in 2014. The beam halo propagation through the ATF2 beamline by means of tracking simulations has been investigated using as input a purely Gaussian and uniform beam halo model.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTY027	SixTrack Simulations of Beam Cleaning During High-beta Operation in the LHC	simulation, proton, experiment, collimation	2060
	R. Bruce CERN, Geneva, Switzerland
	The 1000 m high-beta run in the LHC provided very clean conditions for observing experimental backgrounds. In ATLAS, a much higher background was observed for Beam 2 than for Beam 1, suspected to be caused by upstream showers from beam losses on collimators or aperture. However, no local beam losses were observed in the vicinity. This paper presents SixTrack simulations of the beam cleaning during the high-beta run. The results demonstrate that, for the special optics and collimator settings used, the highest loss location in IR1 is at the TAS absorber just in front of the ATLAS detector, where no beam loss monitor is installed. Furthermore, the highest losses are seen in Beam 2. The results could thus provide a possible explanation of the ATLAS observations, although detailed shower calculations would be needed for a quantitative comparison.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY027
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTY032	Study of Muon Backgrounds in the CLIC Beam Delivery System	shielding, collimation, hadron, betatron	2075
	F.B. Pilicer, E. Pilicer, I. Tapan UU, Bursa, Turkey H. Burkhardt, L. Gatignon, A. Latina, D. Schulte, R. Tomás CERN, Geneva, Switzerland
	We describe the detailed modelling of muon background generation and absorption in the CLIC beam delivery system. The majority of the background muons originates in the first stages of halo collimation. We also discuss options to use magnetised cylindrical iron shields to reduce the muon background flux reaching the detector region.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY032
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTY066	Beam Cleaning in Experimental IRs in HL-LHC for Incoming Beam	collimation, optics, betatron, quadrupole	2181
	H. Garcia Morales Royal Holloway, University of London, Surrey, United Kingdom R. Bruce, S. Redaelli CERN, Geneva, Switzerland
	The HL-LHC will store 675 MJ of energy per beam, about 300 MJ more than the nominal LHC. Due to the increase in stored energy and a different interaction region (IR) optics design, the collimation system for the incoming beam must be revisited in order to avoid dangerous losses that could cause quenches and machine damage. This paper studies the ffectiveness of the current LHC collimation system in intercepting cleaning losses close to the experiments in the HL-LHC. The study reveals that additional tertiary collimators would be beneficial in order to protect not only the final focusing triplets but also the two quadrupoles further upstream.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY066
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTY067	Beam Induced Background Simulation Studies at IR1 with New High Luminosity LHC Layout	optics, simulation, collimation, luminosity	2184
	R. Kwee-Hinzmann, S.M. Gibson JAI, Egham, Surrey, United Kingdom R. Bruce, F. Cerutti, L.S. Esposito, A. Lechner CERN, Geneva, Switzerland S.M. Gibson Royal Holloway, University of London, Surrey, United Kingdom
	Funding: Research supported by FP7 HiLumi LHC – Grant agreement 284404 In the High Luminosity LHC (HL-LHC), the collimation system will be upgraded in the high-luminosity experimental regions. Additional protection is planned for the Q4 and Q5 magnets that are located further upstream of the tertiary collimators that protect the inner triplet magnets. We evaluate the effect of this proposed collimation layout for the incoming beam 1 on machine-induced background in the experimental area of IR1 (ATLAS). The main scenario is the round optics with β∗ of 15 cm, but a flat scenario is also briefly discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY067
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMN059	Design Study and Construction of a Transverse Beam Halo Collimation System for ATF2	wakefield, simulation, collimation, dipole	3062
	N. Fuster-Martínez, A. Faus-Golfe IFIC, Valencia, Spain P. Bambade, S. Liu, S. Wallon LAL, Orsay, France K. Kubo, T. Okugi, T. Tauchi, N. Terunuma KEK, Ibaraki, Japan I. Podadera, F. Toral CIEMAT, Madrid, Spain
	Funding: Work supported by IDC-20121074, FPA2013-47883-C2-1-P and ANR-11-IDEX-0003-02 The feasibility and efficiency of a transverse beam halo collimation system for reducing the background in the ATF2 beamline has been studied in simulations. In this paper the design and construction of a retractable transverse beam halo collimator device is presented. The wakefield induced-impact of a realistic mechanical prototype has been studied with CST PS, as well as the wakefield beam dynamics impact by using the tracking code PLACET.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMN059
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPTY076	RF Performance Studies of Thin-Film Superconductors Using a Sample Host Cavity	cavity, niobium, SRF, operation	3462
	J.T. Maniscalco, D.L. Hall, M. Liepe Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Thin-film superconductors have the potential for reduced cost and for improved SRF performance over traditional bulk niobium superconducting cavities. Materials such as Nb3Sn, multilayer NbN/MgO, and thin-film Nb are currently under investigation for cost reduction or possible improvements in RF losses and accelerating gradients. Due to the complex geometries of traditional RF cavities, it is preferable to use a sample host cavity to study flat samples of the novel materials. The Cornell sample host cavity has been commissioned and has now reached peak magnetic surface fields of 100 mT. We present updates on the recent performance of the cavity.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPTY076
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPWI024	Vacuum Characterization and Improvement for the Jefferson Lab Polarized Electron Source	ion, electron, vacuum, gun	3540
	M.L. Stutzman, P.A. Adderley, M. Poelker JLab, Newport News, Virginia, USA M.A. Mamun Old Dominion University, Norfolk, Virginia, USA
	Operating the JLab polarized electron source with high reliability and long lifetime requires vacuum near the XHV level (<=1x10^-12 Torr). This paper describes ongoing vacuum research at Jefferson Lab including characterization of outgassing rates for surface coatings and heat treatments, ultimate pressure measurements, investigation of pumping including an XHV cryopump, and characterization of ionization gauges in this pressure regime.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWI024
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPF009	Pumping Properties of Cryogenic Surfaces in SIS100	cryogenics, vacuum, simulation, operation	3696
	L.H.J. Bozyk, O.K. Kester, P.J. Spiller GSI, Darmstadt, Germany F. Chill, O.K. Kester IAP, Frankfurt am Main, Germany
	Funding: Work supported by Hic4Fair and BMBF (FKZ:05P12RDRBK). The synchrotron SIS100 of the planned FAIR facility will provide heavy ion beams of highest intensities. The required low charge states are subject to enhanced charge exchange processes in collisions with residual gas molecules. Therefore, highest vacuum quality is crucial for a reliable operation and minimal beam loss. The generation of the required low gas densities relies on the pumping capabilities of the cryogenic beam pipe walls. Most typical gas components in ultra high vacuum are bound by cryocondensation at LHe temperatures, resulting in ultimate low pressures with almost infinite pumping capacity. Hydrogen can not be crycondensated to acceptable low pressures. But if the surface coverage is sufficiently low, it can get bound by cryoadsorption. The pumping capabilities of cryogenic walls for Hydrogen have been investigated for SIS100-like conditions. The measurement results have been used in dynamic vacuum simulations at heavy ion operation. The simulation results are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THPF009
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

MOPJE078

Beam Delivery Simulation - Recent Developments and Optimization

simulation, collider, toolkit, linear-collider

499

J. Snuverink, S.T. Boogert, H. Garcia Morales, S.M. Gibson, R. Kwee-Hinzmann, L.J. Nevay
JAI, Egham, Surrey, United Kingdom
L.C. Deacon
UCL, London, United Kingdom

Funding: Research supported by FP7 HiLumi LHC - grant agreement 284404 and by the STFC via the JAI3 grant
Beam Delivery Simulation (BDSIM) is a particle tracking code that simulates the passage of particles through both the magnetic accelerator lattice as well as their interaction with the material of the accelerator itself. The Geant4 toolkit is used to give a full range of physics processes needed to simulate both the interaction of primary particles and the production and subsequent propagation of secondaries. BDSIM has already been used to simulate linear accelerators such as the International Linear Collider (ILC) and the Compact Linear Collider (CLIC), but it has recently been adapted to simulate circular accelerators as well, producing loss maps for the Large Hadron Collider (LHC). In this paper the most recent developments, which extend BDSIM's functionality as well as improve its efficiency are presented. Improvement and refactorisation of the tracking algorithms are presented alongside improved automatic geometry construction for increased particle tracking speed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE078

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPHA027

Transverse Emittance Measurement at REGAE

emittance, electron, detector, solenoid

837

M. Hachmann, K. Flöttmann
DESY, Hamburg, Germany

The linear accelerator REGAE at DESY produces short and low charged electron bunches, on the one hand to resolve the excitation transitions of atoms temporally by pump probe electron diffraction experiments and on the other hand to investigate principal mechanisms of laser plasma acceleration. For both cases a high quality electron beam is required which can be identified with a small beam emittance. A standard magnet scan is used for the emittance measurement which is in case of a low charged bunch most sensitive to the beam size determination (2nd central moment of a distribution). Therefore the diagnostic and a routine to calculate proper central moments of an arbitrary distribution will be introduced and discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPHA027

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPWI014

Design and Development for the Next Generation X-ray Beam Position Monitor System at the APS

undulator, electron, photon, coupling

1175

B.X. Yang, G. Decker, Y. Jaski, S.-H. Lee, M. Ramanathan, N. Sereno, F. Westferro
ANL, Argonne, Ilinois, USA

Funding: Work performed at Argonne National Laboratory, operated by UChicago Argonne, LLC, for the U.S. Department of Energy under contract DE-AC02-06CH11357.
The proposed Advanced Photon Source (APS) Upgrade will bring storage-ring beam sizes down to several micrometers and require x-ray beam directional stability in 100 nrad range for undulator power exceeding 16 kW. The next generation x-ray beam position monitors (XBPMs) are designed to meet these requirements. We present first commissioning data on the recently installed grazing-incidence insertion device x-ray beam position monitor (GRID-XBPM) based on Cu K-edge x-ray fluorescence from limiting absorbers of the front end for two inline undulators. It demonstrated a 50-fold improvement for signal-to-background ratio over existing photoemission-based XBPMs. Techniques for calibrating the XBPMs will be discussed. We will also present a new XBPM design based Compton scattering from diamond blades. This XBPM is designed for less powerful undulators such as the APS canted-undulator beamlines where each undulator generates < 10 kW of beam power. We will discuss the thermal design of the blade, the optics design of the detector assembly, and computer simulations of expected response to the x-ray beam. Test data of the prototype may be presented if available.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWI014

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPJE032

Updates of the PAL-XFEL Undulator Program

undulator, FEL, electron, controls

1675

D.E. Kim, M.-H. Cho, Y.-G. Jung, H.-S. Kang, I.S. Ko, H.-G. Lee, S.B. Lee, W.W. Lee, B.G. Oh, K.-H. Park, H.S. Suh
PAL, Pohang, Kyungbuk, Republic of Korea
S. Karabekyan, J. Pflüger
XFEL. EU, Hamburg, Germany

Pohang Accelerator Laboratory (PAL) is developing a 0.1 nm SASE based FEL based on 10 GeV S-band linear accelerator named PAL-XFEL. At the first stage, PAL-XFEL needs two undulator lines for photon source. The hard X-ray undulator line requires 18 units of 5 m long hybrid-type conventional planar undulator and soft X-ray line requires 6 units of 5 m long hybrid type planar undulator with additional few EPUs for final polarization control. PAL is developing undulator magnetic structure based on EU-XFEL concepts. The key parameters are min pole gap of 8.3 mm, with period length 26 mm (HXU), 35 mm (SXU), and 5.0 m magnetic length. . In this report, the prototyping, and the development of pole tuning procedure, the impact of the background field error, and the effects of the girder bending on the optical phase error will be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPJE032

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTY016

Study of Background and MDI Design for CEPC

detector, scattering, photon, simulation

2028

Y. Yue, Q. Qin
IHEP, Beijing, People's Republic of China

CEPC is a project designed to obtain a large number of Higgs events by keeping e⁺e⁻ collisions at the center-of-mass energy of 240 GeV and deliver peak luminosity above 10³⁴ cm^-2 s^-1 for each interaction point. The super high energy and the pretty high luminosity will bring some special background problems, which will exert difficulty on the MDI design and the detectors protection. In this article, I will show the simulation result of the main background sources at CEPC and give some suggestions on the MDI design and detectors protection.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY016

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTY019

Realistic Beam Halo Model study in the Extraction Line of ATF2

simulation, optics, electron, diagnostics

2038

N. Fuster-Martínez, A. Faus-Golfe
IFIC, Valencia, Spain
P. Bambade, S. Liu, S. Wallon
LAL, Orsay, France
K. Kubo, T. Okugi, T. Tauchi, N. Terunuma
KEK, Ibaraki, Japan
E. Marín, G.R. White
SLAC, Menlo Park, California, USA

Funding: Work supported by IDC-20101074, FPA2013-47883-C2-1-P and ANR-11-IDEX-0003-02
The understanding and control of the transverse beam halo distributions is an important issue to reduce sources of background noise in Future Linear Colliders (FLC) and specifically at ATF2. A realistic model of the beam halo in the old extraction line of the ATF damping ring was obtained in 2005, based on wire scanner measurements. Recently, new measurements were done in the new extraction line of ATF2, using both wire scanners, in 2013, and Optical Transition Radiation monitors (OTR), in 2014. The beam halo propagation through the ATF2 beamline by means of tracking simulations has been investigated using as input a purely Gaussian and uniform beam halo model.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTY027

SixTrack Simulations of Beam Cleaning During High-beta Operation in the LHC

simulation, proton, experiment, collimation

2060

R. Bruce
CERN, Geneva, Switzerland

The 1000 m high-beta run in the LHC provided very clean conditions for observing experimental backgrounds. In ATLAS, a much higher background was observed for Beam 2 than for Beam 1, suspected to be caused by upstream showers from beam losses on collimators or aperture. However, no local beam losses were observed in the vicinity. This paper presents SixTrack simulations of the beam cleaning during the high-beta run. The results demonstrate that, for the special optics and collimator settings used, the highest loss location in IR1 is at the TAS absorber just in front of the ATLAS detector, where no beam loss monitor is installed. Furthermore, the highest losses are seen in Beam 2. The results could thus provide a possible explanation of the ATLAS observations, although detailed shower calculations would be needed for a quantitative comparison.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY027

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTY032

Study of Muon Backgrounds in the CLIC Beam Delivery System

shielding, collimation, hadron, betatron

2075

F.B. Pilicer, E. Pilicer, I. Tapan
UU, Bursa, Turkey
H. Burkhardt, L. Gatignon, A. Latina, D. Schulte, R. Tomás
CERN, Geneva, Switzerland

We describe the detailed modelling of muon background generation and absorption in the CLIC beam delivery system. The majority of the background muons originates in the first stages of halo collimation. We also discuss options to use magnetised cylindrical iron shields to reduce the muon background flux reaching the detector region.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY032

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTY066

Beam Cleaning in Experimental IRs in HL-LHC for Incoming Beam

collimation, optics, betatron, quadrupole

2181

H. Garcia Morales
Royal Holloway, University of London, Surrey, United Kingdom
R. Bruce, S. Redaelli
CERN, Geneva, Switzerland

The HL-LHC will store 675 MJ of energy per beam, about 300 MJ more than the nominal LHC. Due to the increase in stored energy and a different interaction region (IR) optics design, the collimation system for the incoming beam must be revisited in order to avoid dangerous losses that could cause quenches and machine damage. This paper studies the ffectiveness of the current LHC collimation system in intercepting cleaning losses close to the experiments in the HL-LHC. The study reveals that additional tertiary collimators would be beneficial in order to protect not only the final focusing triplets but also the two quadrupoles further upstream.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY066

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTY067

Beam Induced Background Simulation Studies at IR1 with New High Luminosity LHC Layout

optics, simulation, collimation, luminosity

2184

R. Kwee-Hinzmann, S.M. Gibson
JAI, Egham, Surrey, United Kingdom
R. Bruce, F. Cerutti, L.S. Esposito, A. Lechner
CERN, Geneva, Switzerland
S.M. Gibson
Royal Holloway, University of London, Surrey, United Kingdom

Funding: Research supported by FP7 HiLumi LHC – Grant agreement 284404
In the High Luminosity LHC (HL-LHC), the collimation system will be upgraded in the high-luminosity experimental regions. Additional protection is planned for the Q4 and Q5 magnets that are located further upstream of the tertiary collimators that protect the inner triplet magnets. We evaluate the effect of this proposed collimation layout for the incoming beam 1 on machine-induced background in the experimental area of IR1 (ATLAS). The main scenario is the round optics with β∗ of 15 cm, but a flat scenario is also briefly discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY067

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMN059

Design Study and Construction of a Transverse Beam Halo Collimation System for ATF2

wakefield, simulation, collimation, dipole

3062

N. Fuster-Martínez, A. Faus-Golfe
IFIC, Valencia, Spain
P. Bambade, S. Liu, S. Wallon
LAL, Orsay, France
K. Kubo, T. Okugi, T. Tauchi, N. Terunuma
KEK, Ibaraki, Japan
I. Podadera, F. Toral
CIEMAT, Madrid, Spain

Funding: Work supported by IDC-20121074, FPA2013-47883-C2-1-P and ANR-11-IDEX-0003-02
The feasibility and efficiency of a transverse beam halo collimation system for reducing the background in the ATF2 beamline has been studied in simulations. In this paper the design and construction of a retractable transverse beam halo collimator device is presented. The wakefield induced-impact of a realistic mechanical prototype has been studied with CST PS, as well as the wakefield beam dynamics impact by using the tracking code PLACET.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMN059

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPTY076

RF Performance Studies of Thin-Film Superconductors Using a Sample Host Cavity

cavity, niobium, SRF, operation

3462

J.T. Maniscalco, D.L. Hall, M. Liepe
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Thin-film superconductors have the potential for reduced cost and for improved SRF performance over traditional bulk niobium superconducting cavities. Materials such as Nb3Sn, multilayer NbN/MgO, and thin-film Nb are currently under investigation for cost reduction or possible improvements in RF losses and accelerating gradients. Due to the complex geometries of traditional RF cavities, it is preferable to use a sample host cavity to study flat samples of the novel materials. The Cornell sample host cavity has been commissioned and has now reached peak magnetic surface fields of 100 mT. We present updates on the recent performance of the cavity.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPTY076

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPWI024

Vacuum Characterization and Improvement for the Jefferson Lab Polarized Electron Source

ion, electron, vacuum, gun

3540

M.L. Stutzman, P.A. Adderley, M. Poelker
JLab, Newport News, Virginia, USA
M.A. Mamun
Old Dominion University, Norfolk, Virginia, USA

Operating the JLab polarized electron source with high reliability and long lifetime requires vacuum near the XHV level (<=1x10^-12 Torr). This paper describes ongoing vacuum research at Jefferson Lab including characterization of outgassing rates for surface coatings and heat treatments, ultimate pressure measurements, investigation of pumping including an XHV cryopump, and characterization of ionization gauges in this pressure regime.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWI024

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPF009

Pumping Properties of Cryogenic Surfaces in SIS100

cryogenics, vacuum, simulation, operation

3696

L.H.J. Bozyk, O.K. Kester, P.J. Spiller
GSI, Darmstadt, Germany
F. Chill, O.K. Kester
IAP, Frankfurt am Main, Germany

Funding: Work supported by Hic4Fair and BMBF (FKZ:05P12RDRBK).
The synchrotron SIS100 of the planned FAIR facility will provide heavy ion beams of highest intensities. The required low charge states are subject to enhanced charge exchange processes in collisions with residual gas molecules. Therefore, highest vacuum quality is crucial for a reliable operation and minimal beam loss. The generation of the required low gas densities relies on the pumping capabilities of the cryogenic beam pipe walls. Most typical gas components in ultra high vacuum are bound by cryocondensation at LHe temperatures, resulting in ultimate low pressures with almost infinite pumping capacity. Hydrogen can not be crycondensated to acceptable low pressures. But if the surface coverage is sufficiently low, it can get bound by cryoadsorption. The pumping capabilities of cryogenic walls for Hydrogen have been investigated for SIS100-like conditions. The measurement results have been used in dynamic vacuum simulations at heavy ion operation. The simulation results are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THPF009

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)