IPAC2016 - List of Keywords (background)

Paper	Title	Other Keywords	Page
MOPMB006	First Tests of SuperKEKB Luminosity Monitors during 2016 Single Beam Commissioning	luminosity, vacuum, simulation, scattering	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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MOPMB034	Design and Application of Double-slit Emittance Meter for C-ADS Proton Beams	emittance, rfq, proton, instrumentation	164
	L. Yu, Y.F. Sui, J.X. Zhao, D.C. Zhu IHEP, Beijing, People's Republic of China
	To reduce the beam loss in the high current linac, beam transverse emittance is a key value which has to be characterized. At Institute of High Energy Physics (IHEP) in Beijing the C-ADS project has started beam commissioning. A newly developed double-slit emittance meter (DEM) for pulsed proton beam from the (RFQ) has been installed in the beam line. In this paper principal of operation, instrumentation and programming of emittance meter are discussed. The emittance measurement has been carried out with the newly developed DEM at a beam energy of 3.2 MeV and a beam current of 10 mA. Typical rms emittance for x and y direction are measured to be 0.1303 and 0.1347 π mm mrad，which are well below the design standard of the RFQ.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB034
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MOPMR024	A Versatile Beam Loss Monitoring System for CLIC	electron, quadrupole, beam-losses, cavity	286
	M. Kastriotou, S. Döbert, W. Farabolini, E.B. Holzer, E. Nebot Del Busto, F. Tecker CERN, Geneva, Switzerland M. Kastriotou, E. Nebot Del Busto, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom M. Kastriotou, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom
	The design of a potential CLIC beam loss monitoring (BLM) system presents multiple challenges. To successfully cover the 48 km of beamline, ionisation chambers and optical fibre BLMs are under investigation. The former fulfils all CLIC requirements but would need more than 40000 monitors to protect the whole facility. For the latter, the capability of reconstructing the original loss position with a multi-bunch beam pulse and multiple loss locations still needs to be quantified. Two main sources of background for beam loss measurements are identified for CLIC. The two-beam accelerator scheme introduces so-called crosstalk, i.e. detection of losses originating in one beam line by the monitors protecting the other. Moreover, electrons emitted from the inner surface of RF cavities and boosted by the high RF gradients may produce signals in neighbouring BLMs, limiting their ability to detect real beam losses. This contribution presents the results of dedicated experiments performed in the CLIC Test Facility to quantify the position resolution of optical fibre BLMs in a multi-bunch, multi-loss scenario as well as the sensitivity limitations due to crosstalk and electron field emission.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR024
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MOPMR040	First Steps Towards a Single-Shot Longitudinal Profile Monitor: Study of the Properties of Coherent Smith-Purcell Radiation Using the Surface Current Model	radiation, detector, polarization, simulation	340
	H. Harrison, G. Doucas, I.V. Konoplev, A.J. Lancaster JAI, Oxford, United Kingdom A. Aryshev, K. Lekomtsev, M. Shevelev, N. Terunuma, J. Urakawa KEK, Ibaraki, Japan
	Funding: UK STFC, Leverhulme Trust, Photon and Quantum Basic Research Coordinated Development Program (Ministry of Education, Culture, Sports, Science and Technology, Japan)and JSPS KAKENHI. We propose to use the polarization of coherent Smith-Purcell radiation (cSPr) to separate the signal from background radiation in a single-shot longitudinal bunch profile monitor. We compare simulation and experimental results for the degree of polarization of cSPr generated by a grating with a 1mm periodic structure at the LUCX facility, KEK (Japan). Both experiment and simulation show that the majority of the cSPr signal is polarized in the direction parallel to the grating grooves. The degree of polarization predicted by simulation is higher than the measured result, therefore further investigation is needed to resolve this discrepancy.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR040
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MOPMR041	Experimental and Theoretical Studies of the Properties of Coherent Smith-Purcell Radiation	radiation, polarization, electron, experiment	344
	F. Bakkali Taheri, R. Bartolini, G. Doucas, I.V. Konoplev, A. Reichold JAI, Oxford, United Kingdom J. Barros, N. Delerue LAL, Orsay, France R. Bartolini DLS, Oxfordshire, United Kingdom C.I. Clarke SLAC, Menlo Park, California, USA
	Funding: This work was supported (in parts) by the UK Science and Technology Facilities Council (STFC UK) through grant ST/M003590/1 and The Leverhulme Trust through the International Network Grant IN-2015-012 Previous studies have demonstrated that coherent Smith-Purcell radiation (cSPr) can be used for relativistic electron bunch time profile reconstruction at pico-second and femtosecond scales. The E203 experiments undertaken in May 2015 at FACET (SLAC) were dedicated to the study of some properties of cSPr, namely the azimuthal distribution and the polarization of the radiation. The experimental set up description which allowed such studies will be presented along with the results. To understand the experimental data both semi-analytical and numerical models were studied. The semi-analytical approach was based on the surface-current model, and the 3D particle-in-cell code VSim was used for numerical modeling. The experimental and theoretical studies are compared.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR041
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MOPOY027	Emittance Measurement with Wire Scanners at C-ADS Injector-I	emittance, rfq, simulation, beam-transport	910
	H. Geng, C. Meng, Y.F. Sui, F. Yan, L. Yu, Y.L. Zhao IHEP, Beijing, People's Republic of China
	The transverse emittance at C-ADS injector-I has been measured by the wire scanners at the Medium Energy Beam Transport-I (MEBT1). We have studied the effect of different fitting methods for obtaining the beam sizes on the emittance result, the result will be presented in this paper. The validation study of the quad-scan method with the presence of space charge effect at 10 mA will also be shown, and finally the quad-scan results will be compared with the multi-wire results.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOY027
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TUPMB009	Vibrating Wire Measurements for the XiPAF Permanent Magnet Quadrupoles	multipole, experiment, permanent-magnet, DTL	1124
	B.C. Wang, M.T. Qiu, Z.M. Wang State Key Laboratory of Intense Pulsed Radiation Simulation and Effect, Northwest Institute of Nuclear Technology, Shannxi, People's Republic of China C.T. Du, X.W. Wang, L. Wu, Q.Z. Xing, S.X. Zheng TUB, Beijing, People's Republic of China
	Vibrating wire technique is a promising measure-ment method for small-aperture Permanent Magnet Quadrupoles (PMQs) in linear accelerators and scan-ning nuclear microprobes. In this paper, we describe the improved vibrating wire setup for measuring an individual PMQ with the minimum aperture of several millimeters. This setup is aiming at measuring the magnetic center. The advantage of this setup is that any mechanical measurement on the wire, which may be the main error source, is avoided. Experiments of the 20 mm-aperture Halbach-type PMQs for Xi'an Proton Application Facility (XiPAF) DTL has been carried out. The research results of the magnetic center measurements show a precision of about 10 μm and robustness against the background magnetic field. Results of the magnetic center and field multipoles measurements agree with the ones obtained from the rotating coil.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMB009
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TUPMY003	Development of Muon LINAC for the Muon g-2/EDM Experiment at J-PARC	rfq, acceleration, linac, cavity	1543
	M. Otani, T. Mibe, F. Naito, N. Saito, M. Yoshida KEK, Tsukuba, Japan K. Hasegawa, T. Ito, Y. Kondo JAEA/J-PARC, Tokai-mura, Japan N. Hayashizaki RLNR, Tokyo, Japan Y. Iwashita Kyoto ICR, Uji, Kyoto, Japan Y. Iwata NIRS, Chiba-shi, Japan R. Kitamura University of Tokyo, Tokyo, Japan
	Precision measurements of the muon's anomalous magnetic moment (g-2) and electric dipole moment (EDM) are effective ways to cast light on beyond the standard model of elementary particle physics. The J-PARC E34 experiment aims to measure g-2 with a precision of 0.1 ppm and search for EDM with a sensitivity to 10-{-21} e· cm with high intensity proton beam at J-PARC and a novel technique of making a muon beam with small emittance (the ultra-cold muon beam). The ultra-cold muon beam is generated from a surface muon beam by the thermal muonium (30 meV) production followed by the laser ionization, and acceleration to 212 MeV or 300 MeV/c by the muon dedicated LINAC. The muon LINAC consists of RFQ, inter-digital IH, Disk And Washer (DAW) coupled cell and disk loaded structure. The ultra-cold muons will have an extremely small transverse momentum spread of less than 1 % with a normalized transverse emittance of around 1.5 pi mm-mrad. The muon acceleration to 300 MeV/c will be the first case in the world and it will be one of the base technologies of future accelerator programs. In this talk, design and status of the muon LINAC will be reported.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMY003
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TUPMY024	First Test of The Imperial College Gabor (Plasma) Lens prototype at the Surrey Ion Beam centre	plasma, proton, electron, ion	1598
	P.A. Posocco, J.K. Pozimski, Y. Xia Imperial College of Science and Technology, Department of Physics, London, United Kingdom M.J. Merchant UoM ICS, Manchester, United Kingdom M.J. Merchant The Christie NHS Foundation Trust, Manchester, United Kingdom
	Funding: Funding was provided by the Imperial College Confidence in Concepts scheme. The first plasma (Gabor) lens prototype operating at high electron density was built by the Imperial College London in 2015. In November 2015 the lens was tested at the Ion Beam Centre of the University of Surrey with a 1 MeV proton beam. Over 500 snapshots of the beam hitting a scintillator screen installed 0.5 m downstream of the lens were taken for a wide range of settings. Unexpectedly, instead of over- or underfocusing the incoming particles, the lens converted pencil beams into rings. In addition to the dependence of their radius on the lens settings, periodic features appeared along the circumference, suggesting that the electron plasma was exited into a coherent off-axis rotation. The cause of this phenomenon is under investigation.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMY024
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TUPOW015	Experiment of High Resolution Field Emission Imaging in an rf Photocathode Gun	cathode, electron, experiment, gun	1772
	J.H. Shao, H.B. Chen, J. Shi, X.W. Wu TUB, Beijing, People's Republic of China S.P. Antipov, S.V. Baryshev, C.-J. Jing Euclid TechLabs, LLC, Solon, Ohio, USA M.E. Conde, W. Gai, G. Ha, E.E. Wisniewski ANL, Argonne, Illinois, USA F.Y. Wang SLAC, Menlo Park, California, USA
	The first in situ high resolution field emission (FE) imaging experiment has been carried out on an L-band photocathode gun test stand at Argonne Wakefield Accelerator facility (AWA). Separated strong emitters have been observed to dominate the field emission. Field enhancement factor, beta, of small regions on the cathode has been measured with the imaging system. It is shown that most strong emitters overlaps with the high beta regions. The post surface examinations reveal the origins of ~75% strong emitters overlap with the spots where rf breakdown have occurred. Detailed results are presented in this paper.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW015
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TUPOW049	Expected Results From Channeling Radiation Experiments at Fast	photon, detector, electron, emittance	1873
	T. Sen, D.R. Broemmelsiek, D.R. Edstrom Fermilab, Batavia, Illinois, USA J. Hyun Sokendai, Ibaraki, Japan D. Mihalcea, P. Piot Northern Illinois University, DeKalb, Illinois, USA W.D. Rush KU, Lawrence, Kansas, USA
	Funding: Fermilab is operated by Fermi Research Alliance LLC under DOE contract No. DE-AC02CH11359 The photoinjector at the new Fermilab FAST facility will accelerate electron beams to about 50 GeV. After initial beam commissioning, channeling radiation experiments to generate hard X-rays will be performed. In the initial stage, low bunch charge beams will be used to keep the photon count rate low and avoid pile up in the detector. We report here on the optics solutions, the expected channaling spectrum including background from bremmstrahlung and the use of a Compton scatterer for higher bunch charge operation.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW049
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TUPOW052	LLNL Laser-Compton X-ray Characterization	laser, electron, photon, simulation	1885
	Y. Hwang, T. Tajima UCI, Irvine, California, USA G.G. Anderson, C.P.J. Barty, D.J. Gibson, R.A. Marsh LLNL, Livermore, California, USA
	Funding: This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 Laser-Compton X-rays have been produced at LLNL, and results agree very well with modeling predictions. An X-ray CCD camera and image plates were calibrated and used to characterize the 30 keV X-ray beam. A resolution test pattern was imaged to measure the source size. K-edge absorption images using thin foils confirm the narrow bandwidth of the source and offer electron beam diagnostics.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW052
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TUPOW055	Coronagraph Measurements on the Australian Synchrotron Storage Ring Optical Diagnostic Beamline	synchrotron, extraction, diagnostics, photon	1895
	M.J. Boland, Y.E. Tan SLSA, Clayton, Australia T.M. Mitsuhashi KEK, Ibaraki, Japan
	A coronagraph was constructed on the Optical Diagnostic Beamline at the Australian Synchrotron to observe the tails of the stored beam and the injected beam on the first few turns. Some results are presented with special emphasis on the limitation of the dynamic range due to the quality of the synchrotron light extraction mirror.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW055
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WEPMR009	Magnetic Flux Expulsion Studies in Niobium SRF Cavities	cavity, niobium, cryomodule, survey	2277
	S. Posen, M. Checchin, A.C. Crawford, A. Grassellino, M. Martinello, O.S. Melnychuk, A. Romanenko, D.A. Sergatskov, Y. Trenikhina Fermilab, Batavia, Illinois, USA
	With the recent discovery of nitrogen doping treatment for SRF cavities, ultra-high quality factors at medium accelerating fields are regularly achieved in vertical RF tests. To preserve these quality factors into the cryomodule, it is important to consider background magnetic fields, which can become trapped in the surface of the cavity during cooldown and cause Q₀ degradation. Building on the recent discovery that spatial thermal gradients during cooldown can significantly improve expulsion of magnetic flux, a detailed study was performed of flux expulsion on two cavities with different furnace treatments that are cooled in magnetic fields amplitudes representative of what is expected in a realistic cryomodule. In this contribution, we summarize these cavity results, in order to improve understanding of the impact of flux expulsion on cavity performance.
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WEPOY046	Beam Delivery Simulation: BDSIM - Automatic Geant4 Models of Accelerators	simulation, collider, detector, radiation	3098
	L.J. Nevay, S.T. Boogert, L.C. Deacon, S.M. Gibson, R. Kwee-Hinzmann, W. Shields, J. Snuverink JAI, Egham, Surrey, United Kingdom H. Garcia CERN, Geneva, Switzerland
	Beam Delivery Simulation (BDSIM) is a program that uses a suite of high energy physics software including Geant4, CLHEP & ROOT, that seamlessly tracks particles through accelerators and detectors utilising the full range of particles and physics processes from Geant4. BDSIM has been used to simulate linear colliders such as the International Linear Collider (ILC) and more recently, circular colliders such as the Large Hadron Collider (LHC). The latest developments including improved geometry modelling; external geometry support; process biasing; and a new event display are presented. A significantly revised and improved accompanying tool chain is presented comprising of a series of Python utilities that allow efficient and automatic preparation of models. Furthermore, a library for both ROOT and Python that provides powerful analysis and event viewing after simulation is demonstrated.
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THPOR030	Commissioning and First Performance Studies of a Single Vertical Beam Halo Collimation System at ATF2	photon, collimation, simulation, wakefield	3844
	N. Fuster-Martínez, A. Faus-Golfe IFIC, Valencia, Spain P. Bambade, A. Faus-Golfe, S. Wallon, R.J. Yang LAL, Orsay, France K. Kubo, T. Okugi, T. Tauchi, N. Terunuma KEK, Ibaraki, Japan I. Podadera, F. Toral CIEMAT, Madrid, Spain T. Tauchi, N. Terunuma Sokendai, Ibaraki, Japan
	A single vertical beam halo collimation system has been installed in the ATF2 beamline to reduce the background that could limit the precision of the diagnostics located in the post-IP beamline. On this paper the commissioning and first performance studies of a single vertical beam halo collimation system are reported. Furthermore realistic efficiency studies have been done using the simulation code BDSIM and compared with the first experimental tests.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOR030
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Paper

Title

Other Keywords

Page

MOPMB006

First Tests of SuperKEKB Luminosity Monitors during 2016 Single Beam Commissioning

luminosity, vacuum, simulation, scattering

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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MOPMB034

Design and Application of Double-slit Emittance Meter for C-ADS Proton Beams

emittance, rfq, proton, instrumentation

164

L. Yu, Y.F. Sui, J.X. Zhao, D.C. Zhu
IHEP, Beijing, People's Republic of China

To reduce the beam loss in the high current linac, beam transverse emittance is a key value which has to be characterized. At Institute of High Energy Physics (IHEP) in Beijing the C-ADS project has started beam commissioning. A newly developed double-slit emittance meter (DEM) for pulsed proton beam from the (RFQ) has been installed in the beam line. In this paper principal of operation, instrumentation and programming of emittance meter are discussed. The emittance measurement has been carried out with the newly developed DEM at a beam energy of 3.2 MeV and a beam current of 10 mA. Typical rms emittance for x and y direction are measured to be 0.1303 and 0.1347 π mm mrad，which are well below the design standard of the RFQ.

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MOPMR024

A Versatile Beam Loss Monitoring System for CLIC

electron, quadrupole, beam-losses, cavity

286

M. Kastriotou, S. Döbert, W. Farabolini, E.B. Holzer, E. Nebot Del Busto, F. Tecker
CERN, Geneva, Switzerland
M. Kastriotou, E. Nebot Del Busto, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
M. Kastriotou, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom

The design of a potential CLIC beam loss monitoring (BLM) system presents multiple challenges. To successfully cover the 48 km of beamline, ionisation chambers and optical fibre BLMs are under investigation. The former fulfils all CLIC requirements but would need more than 40000 monitors to protect the whole facility. For the latter, the capability of reconstructing the original loss position with a multi-bunch beam pulse and multiple loss locations still needs to be quantified. Two main sources of background for beam loss measurements are identified for CLIC. The two-beam accelerator scheme introduces so-called crosstalk, i.e. detection of losses originating in one beam line by the monitors protecting the other. Moreover, electrons emitted from the inner surface of RF cavities and boosted by the high RF gradients may produce signals in neighbouring BLMs, limiting their ability to detect real beam losses. This contribution presents the results of dedicated experiments performed in the CLIC Test Facility to quantify the position resolution of optical fibre BLMs in a multi-bunch, multi-loss scenario as well as the sensitivity limitations due to crosstalk and electron field emission.

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MOPMR040

First Steps Towards a Single-Shot Longitudinal Profile Monitor: Study of the Properties of Coherent Smith-Purcell Radiation Using the Surface Current Model

radiation, detector, polarization, simulation

340

H. Harrison, G. Doucas, I.V. Konoplev, A.J. Lancaster
JAI, Oxford, United Kingdom
A. Aryshev, K. Lekomtsev, M. Shevelev, N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan

Funding: UK STFC, Leverhulme Trust, Photon and Quantum Basic Research Coordinated Development Program (Ministry of Education, Culture, Sports, Science and Technology, Japan)and JSPS KAKENHI.
We propose to use the polarization of coherent Smith-Purcell radiation (cSPr) to separate the signal from background radiation in a single-shot longitudinal bunch profile monitor. We compare simulation and experimental results for the degree of polarization of cSPr generated by a grating with a 1mm periodic structure at the LUCX facility, KEK (Japan). Both experiment and simulation show that the majority of the cSPr signal is polarized in the direction parallel to the grating grooves. The degree of polarization predicted by simulation is higher than the measured result, therefore further investigation is needed to resolve this discrepancy.

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MOPMR041

Experimental and Theoretical Studies of the Properties of Coherent Smith-Purcell Radiation

radiation, polarization, electron, experiment

344

F. Bakkali Taheri, R. Bartolini, G. Doucas, I.V. Konoplev, A. Reichold
JAI, Oxford, United Kingdom
J. Barros, N. Delerue
LAL, Orsay, France
R. Bartolini
DLS, Oxfordshire, United Kingdom
C.I. Clarke
SLAC, Menlo Park, California, USA

Funding: This work was supported (in parts) by the UK Science and Technology Facilities Council (STFC UK) through grant ST/M003590/1 and The Leverhulme Trust through the International Network Grant IN-2015-012
Previous studies have demonstrated that coherent Smith-Purcell radiation (cSPr) can be used for relativistic electron bunch time profile reconstruction at pico-second and femtosecond scales. The E203 experiments undertaken in May 2015 at FACET (SLAC) were dedicated to the study of some properties of cSPr, namely the azimuthal distribution and the polarization of the radiation. The experimental set up description which allowed such studies will be presented along with the results. To understand the experimental data both semi-analytical and numerical models were studied. The semi-analytical approach was based on the surface-current model, and the 3D particle-in-cell code VSim was used for numerical modeling. The experimental and theoretical studies are compared.

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MOPOY027

Emittance Measurement with Wire Scanners at C-ADS Injector-I

emittance, rfq, simulation, beam-transport

910

H. Geng, C. Meng, Y.F. Sui, F. Yan, L. Yu, Y.L. Zhao
IHEP, Beijing, People's Republic of China

The transverse emittance at C-ADS injector-I has been measured by the wire scanners at the Medium Energy Beam Transport-I (MEBT1). We have studied the effect of different fitting methods for obtaining the beam sizes on the emittance result, the result will be presented in this paper. The validation study of the quad-scan method with the presence of space charge effect at 10 mA will also be shown, and finally the quad-scan results will be compared with the multi-wire results.

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TUPMB009

Vibrating Wire Measurements for the XiPAF Permanent Magnet Quadrupoles

multipole, experiment, permanent-magnet, DTL

1124

B.C. Wang, M.T. Qiu, Z.M. Wang
State Key Laboratory of Intense Pulsed Radiation Simulation and Effect, Northwest Institute of Nuclear Technology, Shannxi, People's Republic of China
C.T. Du, X.W. Wang, L. Wu, Q.Z. Xing, S.X. Zheng
TUB, Beijing, People's Republic of China

Vibrating wire technique is a promising measure-ment method for small-aperture Permanent Magnet Quadrupoles (PMQs) in linear accelerators and scan-ning nuclear microprobes. In this paper, we describe the improved vibrating wire setup for measuring an individual PMQ with the minimum aperture of several millimeters. This setup is aiming at measuring the magnetic center. The advantage of this setup is that any mechanical measurement on the wire, which may be the main error source, is avoided. Experiments of the 20 mm-aperture Halbach-type PMQs for Xi'an Proton Application Facility (XiPAF) DTL has been carried out. The research results of the magnetic center measurements show a precision of about 10 μm and robustness against the background magnetic field. Results of the magnetic center and field multipoles measurements agree with the ones obtained from the rotating coil.

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMB009

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TUPMY003

Development of Muon LINAC for the Muon g-2/EDM Experiment at J-PARC

rfq, acceleration, linac, cavity

1543

M. Otani, T. Mibe, F. Naito, N. Saito, M. Yoshida
KEK, Tsukuba, Japan
K. Hasegawa, T. Ito, Y. Kondo
JAEA/J-PARC, Tokai-mura, Japan
N. Hayashizaki
RLNR, Tokyo, Japan
Y. Iwashita
Kyoto ICR, Uji, Kyoto, Japan
Y. Iwata
NIRS, Chiba-shi, Japan
R. Kitamura
University of Tokyo, Tokyo, Japan

Precision measurements of the muon's anomalous magnetic moment (g-2) and electric dipole moment (EDM) are effective ways to cast light on beyond the standard model of elementary particle physics. The J-PARC E34 experiment aims to measure g-2 with a precision of 0.1 ppm and search for EDM with a sensitivity to 10-{-21} e· cm with high intensity proton beam at J-PARC and a novel technique of making a muon beam with small emittance (the ultra-cold muon beam). The ultra-cold muon beam is generated from a surface muon beam by the thermal muonium (30 meV) production followed by the laser ionization, and acceleration to 212 MeV or 300 MeV/c by the muon dedicated LINAC. The muon LINAC consists of RFQ, inter-digital IH, Disk And Washer (DAW) coupled cell and disk loaded structure. The ultra-cold muons will have an extremely small transverse momentum spread of less than 1 % with a normalized transverse emittance of around 1.5 pi mm-mrad. The muon acceleration to 300 MeV/c will be the first case in the world and it will be one of the base technologies of future accelerator programs. In this talk, design and status of the muon LINAC will be reported.

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMY003

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TUPMY024

First Test of The Imperial College Gabor (Plasma) Lens prototype at the Surrey Ion Beam centre

plasma, proton, electron, ion

1598

P.A. Posocco, J.K. Pozimski, Y. Xia
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
M.J. Merchant
UoM ICS, Manchester, United Kingdom
M.J. Merchant
The Christie NHS Foundation Trust, Manchester, United Kingdom

Funding: Funding was provided by the Imperial College Confidence in Concepts scheme.
The first plasma (Gabor) lens prototype operating at high electron density was built by the Imperial College London in 2015. In November 2015 the lens was tested at the Ion Beam Centre of the University of Surrey with a 1 MeV proton beam. Over 500 snapshots of the beam hitting a scintillator screen installed 0.5 m downstream of the lens were taken for a wide range of settings. Unexpectedly, instead of over- or underfocusing the incoming particles, the lens converted pencil beams into rings. In addition to the dependence of their radius on the lens settings, periodic features appeared along the circumference, suggesting that the electron plasma was exited into a coherent off-axis rotation. The cause of this phenomenon is under investigation.

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMY024

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TUPOW015

Experiment of High Resolution Field Emission Imaging in an rf Photocathode Gun

cathode, electron, experiment, gun

1772

J.H. Shao, H.B. Chen, J. Shi, X.W. Wu
TUB, Beijing, People's Republic of China
S.P. Antipov, S.V. Baryshev, C.-J. Jing
Euclid TechLabs, LLC, Solon, Ohio, USA
M.E. Conde, W. Gai, G. Ha, E.E. Wisniewski
ANL, Argonne, Illinois, USA
F.Y. Wang
SLAC, Menlo Park, California, USA

The first in situ high resolution field emission (FE) imaging experiment has been carried out on an L-band photocathode gun test stand at Argonne Wakefield Accelerator facility (AWA). Separated strong emitters have been observed to dominate the field emission. Field enhancement factor, beta, of small regions on the cathode has been measured with the imaging system. It is shown that most strong emitters overlaps with the high beta regions. The post surface examinations reveal the origins of ~75% strong emitters overlap with the spots where rf breakdown have occurred. Detailed results are presented in this paper.

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW015

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TUPOW049

Expected Results From Channeling Radiation Experiments at Fast

photon, detector, electron, emittance

1873

T. Sen, D.R. Broemmelsiek, D.R. Edstrom
Fermilab, Batavia, Illinois, USA
J. Hyun
Sokendai, Ibaraki, Japan
D. Mihalcea, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
W.D. Rush
KU, Lawrence, Kansas, USA

Funding: Fermilab is operated by Fermi Research Alliance LLC under DOE contract No. DE-AC02CH11359
The photoinjector at the new Fermilab FAST facility will accelerate electron beams to about 50 GeV. After initial beam commissioning, channeling radiation experiments to generate hard X-rays will be performed. In the initial stage, low bunch charge beams will be used to keep the photon count rate low and avoid pile up in the detector. We report here on the optics solutions, the expected channaling spectrum including background from bremmstrahlung and the use of a Compton scatterer for higher bunch charge operation.

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW049

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TUPOW052

LLNL Laser-Compton X-ray Characterization

laser, electron, photon, simulation

1885

Y. Hwang, T. Tajima
UCI, Irvine, California, USA
G.G. Anderson, C.P.J. Barty, D.J. Gibson, R.A. Marsh
LLNL, Livermore, California, USA

Funding: This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344
Laser-Compton X-rays have been produced at LLNL, and results agree very well with modeling predictions. An X-ray CCD camera and image plates were calibrated and used to characterize the 30 keV X-ray beam. A resolution test pattern was imaged to measure the source size. K-edge absorption images using thin foils confirm the narrow bandwidth of the source and offer electron beam diagnostics.

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TUPOW055

Coronagraph Measurements on the Australian Synchrotron Storage Ring Optical Diagnostic Beamline

synchrotron, extraction, diagnostics, photon

1895

M.J. Boland, Y.E. Tan
SLSA, Clayton, Australia
T.M. Mitsuhashi
KEK, Ibaraki, Japan

A coronagraph was constructed on the Optical Diagnostic Beamline at the Australian Synchrotron to observe the tails of the stored beam and the injected beam on the first few turns. Some results are presented with special emphasis on the limitation of the dynamic range due to the quality of the synchrotron light extraction mirror.

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW055

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WEPMR009

Magnetic Flux Expulsion Studies in Niobium SRF Cavities

cavity, niobium, cryomodule, survey

2277

S. Posen, M. Checchin, A.C. Crawford, A. Grassellino, M. Martinello, O.S. Melnychuk, A. Romanenko, D.A. Sergatskov, Y. Trenikhina
Fermilab, Batavia, Illinois, USA

With the recent discovery of nitrogen doping treatment for SRF cavities, ultra-high quality factors at medium accelerating fields are regularly achieved in vertical RF tests. To preserve these quality factors into the cryomodule, it is important to consider background magnetic fields, which can become trapped in the surface of the cavity during cooldown and cause Q₀ degradation. Building on the recent discovery that spatial thermal gradients during cooldown can significantly improve expulsion of magnetic flux, a detailed study was performed of flux expulsion on two cavities with different furnace treatments that are cooled in magnetic fields amplitudes representative of what is expected in a realistic cryomodule. In this contribution, we summarize these cavity results, in order to improve understanding of the impact of flux expulsion on cavity performance.

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WEPOY046

Beam Delivery Simulation: BDSIM - Automatic Geant4 Models of Accelerators

simulation, collider, detector, radiation

3098

L.J. Nevay, S.T. Boogert, L.C. Deacon, S.M. Gibson, R. Kwee-Hinzmann, W. Shields, J. Snuverink
JAI, Egham, Surrey, United Kingdom
H. Garcia
CERN, Geneva, Switzerland

Beam Delivery Simulation (BDSIM) is a program that uses a suite of high energy physics software including Geant4, CLHEP & ROOT, that seamlessly tracks particles through accelerators and detectors utilising the full range of particles and physics processes from Geant4. BDSIM has been used to simulate linear colliders such as the International Linear Collider (ILC) and more recently, circular colliders such as the Large Hadron Collider (LHC). The latest developments including improved geometry modelling; external geometry support; process biasing; and a new event display are presented. A significantly revised and improved accompanying tool chain is presented comprising of a series of Python utilities that allow efficient and automatic preparation of models. Furthermore, a library for both ROOT and Python that provides powerful analysis and event viewing after simulation is demonstrated.

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOY046

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THPOR030

Commissioning and First Performance Studies of a Single Vertical Beam Halo Collimation System at ATF2

photon, collimation, simulation, wakefield

3844

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

A single vertical beam halo collimation system has been installed in the ATF2 beamline to reduce the background that could limit the precision of the diagnostics located in the post-IP beamline. On this paper the commissioning and first performance studies of a single vertical beam halo collimation system are reported. Furthermore realistic efficiency studies have been done using the simulation code BDSIM and compared with the first experimental tests.

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOR030

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