IPAC2011 - List of Keywords (shielding)

Paper	Title	Other Keywords	Page
MOPC137	Medium Power 352 MHz Solid State Pulsed RF Amplifiers for the CERN Linac4 Project	controls, linac, cavity, rf-amplifier	400
	J.C. Broere, J. Marques Balula CERN, Geneva, Switzerland Y. Gomez LPSC, Grenoble Cedex, France M. Rossi DBE, Padova, Italy
	Economic, modular and highly linear pulsed RF amplifiers have recently been developed to be used for the three Buncher cavities in the CERN Linac4. The amplifiers are water cooled and can provide up to 33 kW pulsed RF power, 1.5 msec pulse length and 50 Hz repetition rate. Furthermore a 60 kWatt unit is under construction to provide the required RF Power for the Debuncher cavity. The concept is based on 1.2 kW RF power modules using the latest 6th generation LDMOS technology. For integration into the CERN control environment the amplifiers have an internal industrial controller, which will provide easy control and extended diagnostic functions. This paper describes the construction, performance, including linearity, phase stability and EMC compliance tests.

MOPC140	Phase and Frequency Locked Magnetrons for SRF Sources	controls, cavity, resonance, SRF	406
	M.L. Neubauer, M.A.C. Cummings, A. Dudas, R.P. Johnson, R. Sah Muons, Inc, Batavia, USA A. Moretti, M. Popovic Fermilab, Batavia, USA
	Typically, high power sources for accelerator applications are multi-megawatt microwave tubes that may be combined together to form ultra-high-power localized power stations. The RF power is then distributed to multiple strings of cavities through high power waveguide systems which are problematic in terms of expense, efficiency, and reliability. Magnetrons are the lowest cost microwave source in dollars/kW, and they have the highest efficiency (typically greater than 85%). However, the frequency stability and phase stability of magnetrons are not adequate, when magnetrons are used as power sources for accelerators. Novel variable frequency cavity techniques have been developed which will be utilized to phase and frequency lock magnetrons, allowing their use for either individual cavities, or cavity strings. Ferrite or YIG (Yttrium Iron Garnet) materials will be attached in the regions of high magnetic field of radial-vaned, π−mode structures of a selected ordinary magnetron. The microwave characteristics of several materials have been tested with magnetic fields to control the frequency of the magnetron. These results will be presented and an optimum material chosen.

MOPS052	Analytical and Numerical Calculations of Beam Pipe Impedances at Low Frequencies with Application to Thin SIS100 Pipe	impedance, coupling, synchrotron, betatron	721
	U. Niedermayer, O. Boine-Frankenheim, L. Hänichen TEMF, TU Darmstadt, Darmstadt, Germany
	The projected fast ramped synchrotron SIS100 for FAIR uses an elliptical stainless steel beam pipe of 0.3 mm thickness. The lowest coherent betatron sidebands reach down to 100 kHz which demands accurate impedance calculations in the low frequency (LF) regime. For these frequencies, i.e. skin depth greater than wall thickness, structures behind the pipe may contribute to the impedance. Due to the extremely large wake length numerical methods in the time domain are not applicable. The longitudinal and transverse impedance of the thin SIS100 beam pipe including structures behind the pipe are obtained numerically by a method using power loss in the frequency domain. We compare different analytical models for simplified pipe structures to the numerical results. The dc and ultra-relativistic limits are investigated. The interpretation of bench measurements in the LF regime is discussed.

MOPZ008	Particle Production Simulations for the Neutrino Factory Target	target, proton, factory, simulation	835
	J.J. Back University of Warwick, Coventry, United Kingdom X.P. Ding UCLA, Los Angeles, California, USA I. Efthymiopoulos, S.S. Gilardoni, O.M. Hansen, G. Prior CERN, Geneva, Switzerland H.G. Kirk, N. Souchlas BNL, Upton, Long Island, New York, USA R.J. Weggel Particle Beam Lasers, Inc., Northridge, California, USA
	Funding: EU FP7 EUROnu WP3 In the International Design Study for the Neutrino Factory (IDS-NF), a proton beam with a kinetic energy between 5 and 15 GeV interacts with a liquid mercury jet target in order to produce pions that will decay to muons, which in turn decay to neutrinos. The target is situated in a solenoidal field tapering from 20 T down to 1.5 T over a length of several metres, allowing for an optimised capture of pions in order to produce a useful muon beam for the machine. We present results of target particle production calculations using MARS, FLUKA and G4BEAMLINE simulation codes.

TUPO031	The Shielding Design of BERLinPro	neutron, electron, radiation, linac	1503
	K. Ott, M. Helmecke HZB, Berlin, Germany
	Funding: Funded by the Bundesministerium für Bildung und Forschung and by the Land Berlin. The Helmholtz-Zentrum Berlin started in January 2011 the design and construction of the Berlin Energy Recovery Linac Project BERLinPro as a demonstrator of ERL science and technology. BERLinPro consists of a SRF photo injector, a merger, superconducting booster and linac modules, the ring and a beamdump. The energy is 50 MeV, the maximum current is 100 mA (cw), acceleration to higher energies is an option for the future. The low energy parts of the machine are operated at about 10 MeV. Due to the potential radiation hazard posed by the tremendous beampower the facility will be placed subterraneously. The shielding concept is presented here. We used the Monte Carlo code FLUKA to calculate the details of the shielding, activations, energy doses for radiation damage and energy spectra for realistic scenarios. Due to computing time reasons we used FLUKA calculations in the 50 MeV to 1 GeV range to derive analytical formulas for the vertical shielding. Extrapolation of existing formulas valid in the GeV range (or below 100 MeV) are not applicable because of the rapidly increasing cross section of photo pion production between 100 and 200 MeV.

TUPS012	The Present Status of Vacuum System of XFEL in SPring-8	vacuum, electron, undulator, laser	1542
	T. Bizen RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan T. Hasegawa RIKEN/SPring-8, Hyogo, Japan
	The vacuum component assembly and installation were completed by February in 2011. The total length of the vacuum system is about 630 m. A 455 sputter ion pumps and a 10⁸ NEG cartridge pumps generate vacuum. The average pressures are on the order of ·10^-7 Pa or less. The flange developed for C-band waveguide shows high reliability of vacuum seal.

TUPS013	Development of the H0 Dump Branch Duct for the Additional Collimation System in J-PARC RCS	septum, collimation, beam-losses, vacuum	1545
	M. Yoshimoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	For the new collimation system in the J-PARC RCS, we have the H0 branch duct installed at the dump septum magnet remodeled. This new branch duct is made of the two kinds of the stainless steels as follows; austenitic stainless steel, SUS316L and ferritic stainless steel, SUS430. In order to research on the property of the SUS430, test ducts were made in various heat-treating condition. In this presentation, we report the design of the new H0 branch duct and the study results with the test ducts.

TUPS017	The LHC Experimental Beam Pipe Neon Venting, Pumping and Conditioning	injection, vacuum, ion, monitoring	1557
	V. Baglin, G. Bregliozzi, D. Calegari, J.M. Jimenez, G. Lanza, G. Schneider CERN, Geneva, Switzerland
	The experimental vacuum chambers of the four LHC experiments (ATLAS, CMS, LHCb and ALICE) are mechanically optimized in order to be transparent to particles. In order to grant their mechanical stability and to avoid any overstress, every time there was a request for detector opening or closing and for working in the vicinity of the vacuum chamber, the experimental beam vacuum chambers have been vented to atmospheric pressure. Since the LHC start up a safety procedure has been applied to mechanically secure the four experimental beam pipes during each long technical stop. Ultra-pure neon was used to preserve at best the NEG pumping efficiency. Up to now more than 15 neon injections and pump down have been performed without detecting any reduction of the NEG efficiency. This paper describes the Gas Injection System performances and the main points of the venting and pumping procedure. Details of the experimental beam pipe vacuum recovery and conditioning are presented for each of the four LHC experiments (ATLAS, CMS, LHCb and ALICE).

TUPS039	Reduction of Magnetic Interference on the Position Sensors of the LHC Collimators	simulation, radiation, dipole	1623
	A. Masi, M. Lamberti, R. Losito, M. Martino CERN, Geneva, Switzerland
	The jaws of the LHC collimators have to be positioned with respect to the beam with an accuracy of 20 μm. On some collimators, installed in the LHC transfer lines from SPS, huge reading errors of several tens of micrometers have been observed on the Linear Variable Differential Transformer (LVDT) positioning sensors in synchronization with the variable magnetic field produced by the feed cables of the pulsed resistive dipoles of the transfer line. In this paper we introduce and describe in detail the problem, the model developed using FLUXTM for the simulation of the magnetic flux density generated by the current cables in the complex environment of an LHC transfer line, and the magnetic shielding we designed and implemented. Finally, we compare the results of simulations with experimental measurements taken during on-line pulsed magnets test campaigns.

TUPS045	IFMIF/EVEDA Beam Dump Shielding: Optimized Design of the Front Part	radiation, photon, neutron, diagnostics	1635
	M. García, D. Lopez, A. Mayoral, F. Ogando, J. Sanz, P. Sauvan UNED, Madrid, Spain J.M. Arroyo, B. Brañas CIEMAT, Madrid, Spain
	The Beam Dump of the IFMIF/EVEDA accelerator prototype, designed to stop deuteron beam with energy up to 9 MeV and a maximum beam power of 1.12 MW, needs to fulfill radioprotection requirements. The deuteron beam collides with the beam stop and neutron and photon sources are produced. The objective of this paper is to design and justify the front part of the local shielding of the Beam Dump that complies with radiation limits for workers during beam-off phases. This shielding must allow unrestricted maintenance operations inside the vault, where the accelerator is located, after a reasonable cooling time after shutdown. In doing so, two main handicaps have been overcome. On one hand, the reliability of the traditionally used Monte Carlo codes such as MCNPX and PHITS has demonstrated to be very poor for deuteron transport at these low energies. In order to solve this lack, the MCUNED code using TENDL library is proposed to be used for deuteron transport and the prediction of the neutron and photon sources. On the other hand, the lack of space in the area dedicated to the last part of the accelerator demands a specially optimized shielding solution.

TUPS048	Equipment and Techniques for the Replacement of the ISIS Proton Beam to Target Window	target, radiation, proton, neutron	1638
	S.D. Gallimore, S.J.S. Jago STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	The ISIS Spallation Neutron Source has been in operation at the Rutherford Appleton Laboratory for over 25 years. Much of the original equipment installed during the construction of the facility is still in operation. The window separating the proton beam transfer line from the neutron target is a key component in the accelerator complex. During the operational life of the Beam Entry Window it has absorbed a considerable amount of energy deposited from the proton beam as it passes from the accelerator vacuum to the target area. Due to the difficulties in accessing and handling the window assembly, a decision was made to replace this component in a planned maintenance period. This paper describes the specialist remote handling equipment and techniques that were developed during the 3 year build up to the removal and replacement of the of the highly active Beam Entry Window.

TUPS053	A Target Magnet System for a Muon Collider and Neutrino Factory	target, radiation, factory, collider	1650
	H.G. Kirk BNL, Upton, Long Island, New York, USA V.B. Graves ORNL, Oak Ridge, Tennessee, USA K.T. McDonald PU, Princeton, New Jersey, USA N. Souchlas, R.J. Weggel Particle Beam Lasers, Inc., Northridge, California, USA
	Funding: This work is supported in part by the US DOE Contract NO. DE-AC02-98CH10886. The target system envisioned for a Muon Collider or Neutrino Factory includes a 20-T solenoid field surrounding a mercury jet target with the field tapering to 1.5 T 15 m downstream of the target. A principal challenge is to shield the superconducting magnets from the radiation issuing from the 4-MW proton beam impacting the target. We describe a solution which will deliver the desired field while being capable of tolerating the intense radiation environment surrounding the target.

TUPS059	SPS WANF Dismantling: A Large Scale-Decommissioning Project at CERN	radiation, target, feedback, ion	1668
	S. Evrard, Y. Algoet, N. Conan, D. DePaoli, I. Efthymiopoulos, S. Fumey, H. Gaillard, J.L. Grenard, D. Grenier, A. Pardons, E. Paulat, Y.D.R. Seraphin, M. Tavlet, C. Theis, H. Vincke CERN, Geneva, Switzerland
	The operation of the SPS (Super Proton Synchrotron) West Area Neutrino Facility (WANF) was halted in 1998. In 2010 a large scale-decommissioning of this facility was conducted. Besides CERN’s commitment to remove non-operational facilities, the additional motivation was the use of the installation (underground tunnels and available infrastructure) for the new HiRadMat facility, which is designed to study the impact of high-intensity pulsed beams on accelerator components and materials. The removal of 800 tons of radioactive equipment and the waste management according to the ALARA (As Low As Reasonably Achievable) principles were two major challenges. This paper describes the solutions implemented and the lessons learnt confirming that the decommissioning phase of a particle accelerator must be carefully studied as from the design stage.

WEPC108	CSR Impedance for an Ultrarelativistic Beam moving in a Curved Trajectory	impedance, vacuum, resonance, radiation	2268
	D.M. Zhou, K. Ohmi, K. Oide KEK, Ibaraki, Japan
	A dedicated computer code, CSRZ, has been developed to calculate the coherent synchrotron radiation (CSR) impedance for an ultrarelativistic beam moving in a curved trajectory. Following the pioneering work of T. Agoh and K. Yokoya, the code solves the parabolic equation in the frequency domain in a curvilinear coordinate system. The beam is assumed to move along a vacuum chamber which has a uniform rectangular cross section but with variable bending radius. Using this code, we did investigations in calculating the longitudinal CSR impedance of a single and a series of bending magnets. The calculation results indicate that the shielding effect due to outer chamber wall can be well explained by a simple optical approximation model at high frequencies. The CSR fields reflected by the outer wall may interfere with each other in a long bending magnet and lead to sharp narrow peaks in the CSR impedance. T. Agoh and K. Yokoya, Phys. Rev. ST Accel. Beams, 7(5):054403 (2004).

WEPC165	Monte Carlo Simulation of the Total Dose Distribution around the 12 MeV UPC Race-track Microtron and Radiation Shielding Calculations	radiation, simulation, target, beam-losses	2370
	C. de la Fuente, M.A. Duch, Yu.A. Kubyshin UPC, Barcelona, Spain V.I. Shvedunov MSU, Moscow, Russia
	The Technical University of Catalonia is building a miniature 12 MeV electron race-track microtron for medical applications. In the paper we study the leakage radiation caused by beam losses inside the accelerator head, as well as the bremstrahlung radiation produced by the primary beam in the commissioning setting. Results of Monte Carlo simulations using the PENELOPE code are presented and two shielding schemes, global and local, are studied. The obtained shielding parameters are compared with estimates based on international recommendations of the radiation safety standards.

WEPC166	Licensing and Safety Issues of the ESS Accelerator	radiation, target, beam-losses, neutron	2373
	P.E.T. Jacobsson, M. Brandin, D. Ene, T. Hansson ESS, Lund, Sweden
	The licensing process for the European Spallation Source (ESS) has started up. The process includes both an application to the Environmental Court in Sweden as well as the application towards the Swedish Radiation Protection Authority (SSM). The applications will be based on an Environmental Impact Assessment EIA) and a Safety Analysis Report (SAR). One important step has been to define which regulations that apply for ESS. ESS has also set up General Safety Objectives (GSO). Based on the GSO and the legal requirements, the process design of the whole ESS facility is ongoing. This paper will focus upon the radiation safety issues related to the accelerator. This includes items as radiation shielding, personal protection system and operation emissions. Analyses and calculations, based on a preliminary design and layout of the ESS accelerator, will be presented. Discussion is made on issues like shielding material, shielding design and analysis models.

WEPO006	Suppression of Leakage Fields from DC Magnets in J-PARC 3 GeV RCS	beam-losses, extraction, septum, vacuum	2412
	M. Yoshimoto, H. Harada, N. Hayashi, H. Hotchi, M. Kinsho, P.K. Saha, K. Yamamoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	In the J-PARC 3 GeV RCS, we found that DC leakage fields from the extraction beam line significantly affected the beam. For this issue, we installed additional shields and got the 40% reduction of the DC leakage field. Thus the circulating beam loss was successfully reduced. In this presentation, we report the detail of the shield structure and the results of the beam studies.

THPC146	The Radiated EMI Isolation for TPS Kicker Magnet*	kicker, radiation, electromagnetic-fields, controls	3227
	C.S. Chen, C.K. Chan, C.L. Chen, Y.L. Chu, K.H. Hsu, C.Y. Kuo, Y.-H. Liu, C.-S. Yang NSRRC, Hsinchu, Taiwan
	Electromagnetic interference is a critical problem for electronic equipment, especially for those sophisticated measuring sensors using in TLS. Therefore, lots of efforts have been made to isolate the EM noise from the kicker magnets. In this article, different thicknesses of aluminum chambers are applied to block the radiated EM noise. Furthermore, the different widths of slits simulate the necessary openings on kicker assembly. According to the results of small-scale experiment, some parameters are obtained to design the enclosure of kicker magnet. Compared the results with the data from the original scale kicker, these parameters provide a believable guideline in the beginning of design status.

THPC186	Heat Load for the APS Superconducting Undulator	photon, radiation, simulation, undulator	3332
	L.E. Boon, A.F. Garfinkel Purdue University, West Lafayette, Indiana, USA K.C. Harkay ANL, Argonne, USA
	Funding: Work supported by U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. The APS Upgrade calls for the development and commissioning of a superconducting undulator (SCU) at the Advanced Photon Source (APS), a 7-GeV electron synchrotron. The first SCU will be installed in June 2012. Until then, simulations such as SYNRAD3D will be used to understand and reduce the heat load on the cryo-system from primary and secondary photons. Current calculations predict that primary photons will distribute 0.5W/m on the chamber walls of the cryostat. SYNRAD3D will be used to calculate the ratio of primary and secondary photons to calculate the heat load due to secondary photons. Previous simulations were of only one sector of the APS accelerator. Simulated here are multiple sectors, to include photons back scattered from downstream photon absorbers.

THPS055	Controlling Beamloss at Injection into the LHC	injection, beam-losses, emittance, kicker	3553
	B. Goddard, F. Alessio, W. Bartmann, P. Baudrenghien, V. Boccone, C. Bracco, M. Brugger, K. Cornelis, B. Dehning, A. Di Mauro, L.N. Drosdal, E.B. Holzer, W. Höfle, R. Jacobsson, V. Kain, M. Meddahi, V. Mertens, A. Nordt, J.A. Uythoven, D. Valuch, S. Weisz, E.N. del Busto CERN, Geneva, Switzerland R. Appleby UMAN, Manchester, United Kingdom
	Losses at injection into the superconducting LHC can adversely affect the machine performance in several important ways. The high injected beam intensity and energy mean that precautions must be taken against damage and quenches, including collimators placed close to the beam in the injection regions. Clean injection is essential, to avoid spurious signals on the sensitive beam loss monitoring system which will trigger beam dumps. In addition, the use of the two injection insertions to house downstream high energy physics experiments brings constraints on permitted beam loss levels. In this paper the sources of injection beam loss are discussed together with the contributing factors and various issues experienced in the first full year of LHC operation. Simulations are compared with measurement, and the implemented and planned mitigation measures and diagnostic improvements are described. An outlook for future LHC operation is given.

THPS065	Upgraded X-band 950 KeV Linac X-ray Source for On-site Inspection at Petrochemical Complex	linac, status, coupling, site	3574
	M. Jin, K. Demachi, K. Dobashi, H.F. Jin, T. Natsui, M. Uesaka The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan J. Kusano, N. Nakamura, M. Yamamoto Accuthera Inc., Kawasaki, Kanagawa, Japan E. Tanabe AET, Kawasaki-City, Japan
	Abstract―Our portable X-band (9.3GHz) 950KeV linac has been successfully upgraded. The problems of RF power oscillation, beam current oscillation and reduction and finally lack of X-ray intensity were solved by replacing the axial coupling cavities with the side-coupled ones. Designed X-ray dose rate of 0.05 Sv/min@1m is going to be achieved. Length of the accelerating tube is reduced to less than 25 cm. X-ray source part with the local radiation shielding is connected by the flexible waveguide with the box of the 300 kW　magnetron and cooling unit. The total system consists of the three suit-case-size units, the last of which is one for the electric power supply. Even on-line dynamic transmission imaging is available by using the high intensity X-ray camera. Demonstration of the measurement of wall thinning of metal pipes with thick thermal shielding is under way. Updated measurement results will be presented. KEYWORDS: portable X-band linac X-ray source, on-site high energy X-ray inspection, petrochemical complex

THPS068	A Proton Therapy Test Facility: The Radiation Protection Design	proton, radiation, neutron, simulation	3583
	S. Sandri, M.C. Carpanese, G. Ottaviano, L. Picardi, C. Poggi, C. Ronsivalle ENEA C.R. Frascati, Frascati (Roma), Italy
	A proton therapy test facility is planned to be sited in the Frascati ENEA Research Center, in Italy. A 30 m long, 3 m wide bunker has to be designed to host a proton linear accelerator with a low beam current, lower than 10 nA in average, and an energy up to 150 MeV. The accelerator will be part of the TOP-IMPLART project for deep tumors treatment. The design of the 150 MeV accelerator is under study and the radiation protection solutions are considered in this phase. The linear accelerator has some safety advantages if compared to cyclotrons and synchrotrons. It can be easily housed in the long, narrow tunnel. The main radiation losses during the acceleration process occur below 20 MeV, with a low neutron production. As a consequence the barriers needed should be substantially lighter than the one used for other types of machines. In the paper the simulation models and the calculation performed with Monte Carlo codes are described. The related results are presented together with those assessed by using published experimental data. Considerations about workers and population protection are issued in the conclusions.

FRXAA01	Theory of Microwave Instability and Coherent Synchrotron Radiation in Electron Storage Rings	impedance, synchrotron, electron, storage-ring	3774
	Y. Cai SLAC, Menlo Park, California, USA
	Funding: This work was supported by Department of Energy Contract No. DE-AC02-76SF00515. Bursting of coherent synchrotron radiation has been observed and in fact used to generate THz radiation in many electron storage rings. In order to understand and control the bursting, we return to the study of the microwave instability. In this talk, we will report on the theoretical understanding, including recent developments, of the microwave instability in electron storage rings. The historical progress of the theories will be surveyed, starting from the dispersion relation of coasting beams, to the work of Sacherer on a bunched beam, and ending with the Oide and Yokoya method of discretization. This theoretical survey will be supplemented with key experimental results over the years. Finally, we will describe the recent theoretical development of utilizing the Laguerre polynomials in the presence of potential-well distortion. This self-consistent method will be applied to study the microwave instability driven by commonly known impedances, including that of coherent synchrotron radiation.
	Slides FRXAA01 [0.948 MB]

Paper

Title

Other Keywords

Page

MOPC137

Medium Power 352 MHz Solid State Pulsed RF Amplifiers for the CERN Linac4 Project

controls, linac, cavity, rf-amplifier

400

J.C. Broere, J. Marques Balula
CERN, Geneva, Switzerland
Y. Gomez
LPSC, Grenoble Cedex, France
M. Rossi
DBE, Padova, Italy

Economic, modular and highly linear pulsed RF amplifiers have recently been developed to be used for the three Buncher cavities in the CERN Linac4. The amplifiers are water cooled and can provide up to 33 kW pulsed RF power, 1.5 msec pulse length and 50 Hz repetition rate. Furthermore a 60 kWatt unit is under construction to provide the required RF Power for the Debuncher cavity. The concept is based on 1.2 kW RF power modules using the latest 6th generation LDMOS technology. For integration into the CERN control environment the amplifiers have an internal industrial controller, which will provide easy control and extended diagnostic functions. This paper describes the construction, performance, including linearity, phase stability and EMC compliance tests.

MOPC140

Phase and Frequency Locked Magnetrons for SRF Sources

controls, cavity, resonance, SRF

406

M.L. Neubauer, M.A.C. Cummings, A. Dudas, R.P. Johnson, R. Sah
Muons, Inc, Batavia, USA
A. Moretti, M. Popovic
Fermilab, Batavia, USA

Typically, high power sources for accelerator applications are multi-megawatt microwave tubes that may be combined together to form ultra-high-power localized power stations. The RF power is then distributed to multiple strings of cavities through high power waveguide systems which are problematic in terms of expense, efficiency, and reliability. Magnetrons are the lowest cost microwave source in dollars/kW, and they have the highest efficiency (typically greater than 85%). However, the frequency stability and phase stability of magnetrons are not adequate, when magnetrons are used as power sources for accelerators. Novel variable frequency cavity techniques have been developed which will be utilized to phase and frequency lock magnetrons, allowing their use for either individual cavities, or cavity strings. Ferrite or YIG (Yttrium Iron Garnet) materials will be attached in the regions of high magnetic field of radial-vaned, π−mode structures of a selected ordinary magnetron. The microwave characteristics of several materials have been tested with magnetic fields to control the frequency of the magnetron. These results will be presented and an optimum material chosen.

MOPS052

Analytical and Numerical Calculations of Beam Pipe Impedances at Low Frequencies with Application to Thin SIS100 Pipe

impedance, coupling, synchrotron, betatron

721

U. Niedermayer, O. Boine-Frankenheim, L. Hänichen
TEMF, TU Darmstadt, Darmstadt, Germany

The projected fast ramped synchrotron SIS100 for FAIR uses an elliptical stainless steel beam pipe of 0.3 mm thickness. The lowest coherent betatron sidebands reach down to 100 kHz which demands accurate impedance calculations in the low frequency (LF) regime. For these frequencies, i.e. skin depth greater than wall thickness, structures behind the pipe may contribute to the impedance. Due to the extremely large wake length numerical methods in the time domain are not applicable. The longitudinal and transverse impedance of the thin SIS100 beam pipe including structures behind the pipe are obtained numerically by a method using power loss in the frequency domain. We compare different analytical models for simplified pipe structures to the numerical results. The dc and ultra-relativistic limits are investigated. The interpretation of bench measurements in the LF regime is discussed.

MOPZ008

Particle Production Simulations for the Neutrino Factory Target

target, proton, factory, simulation

835

J.J. Back
University of Warwick, Coventry, United Kingdom
X.P. Ding
UCLA, Los Angeles, California, USA
I. Efthymiopoulos, S.S. Gilardoni, O.M. Hansen, G. Prior
CERN, Geneva, Switzerland
H.G. Kirk, N. Souchlas
BNL, Upton, Long Island, New York, USA
R.J. Weggel
Particle Beam Lasers, Inc., Northridge, California, USA

Funding: EU FP7 EUROnu WP3
In the International Design Study for the Neutrino Factory (IDS-NF), a proton beam with a kinetic energy between 5 and 15 GeV interacts with a liquid mercury jet target in order to produce pions that will decay to muons, which in turn decay to neutrinos. The target is situated in a solenoidal field tapering from 20 T down to 1.5 T over a length of several metres, allowing for an optimised capture of pions in order to produce a useful muon beam for the machine. We present results of target particle production calculations using MARS, FLUKA and G4BEAMLINE simulation codes.

TUPO031

The Shielding Design of BERLinPro

neutron, electron, radiation, linac

1503

K. Ott, M. Helmecke
HZB, Berlin, Germany

Funding: Funded by the Bundesministerium für Bildung und Forschung and by the Land Berlin.
The Helmholtz-Zentrum Berlin started in January 2011 the design and construction of the Berlin Energy Recovery Linac Project BERLinPro as a demonstrator of ERL science and technology. BERLinPro consists of a SRF photo injector, a merger, superconducting booster and linac modules, the ring and a beamdump. The energy is 50 MeV, the maximum current is 100 mA (cw), acceleration to higher energies is an option for the future. The low energy parts of the machine are operated at about 10 MeV. Due to the potential radiation hazard posed by the tremendous beampower the facility will be placed subterraneously. The shielding concept is presented here. We used the Monte Carlo code FLUKA to calculate the details of the shielding, activations, energy doses for radiation damage and energy spectra for realistic scenarios. Due to computing time reasons we used FLUKA calculations in the 50 MeV to 1 GeV range to derive analytical formulas for the vertical shielding. Extrapolation of existing formulas valid in the GeV range (or below 100 MeV) are not applicable because of the rapidly increasing cross section of photo pion production between 100 and 200 MeV.

TUPS012

The Present Status of Vacuum System of XFEL in SPring-8

vacuum, electron, undulator, laser

1542

T. Bizen
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
T. Hasegawa
RIKEN/SPring-8, Hyogo, Japan

The vacuum component assembly and installation were completed by February in 2011. The total length of the vacuum system is about 630 m. A 455 sputter ion pumps and a 10⁸ NEG cartridge pumps generate vacuum. The average pressures are on the order of ·10^-7 Pa or less. The flange developed for C-band waveguide shows high reliability of vacuum seal.

TUPS013

Development of the H0 Dump Branch Duct for the Additional Collimation System in J-PARC RCS

septum, collimation, beam-losses, vacuum

1545

M. Yoshimoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

For the new collimation system in the J-PARC RCS, we have the H0 branch duct installed at the dump septum magnet remodeled. This new branch duct is made of the two kinds of the stainless steels as follows; austenitic stainless steel, SUS316L and ferritic stainless steel, SUS430. In order to research on the property of the SUS430, test ducts were made in various heat-treating condition. In this presentation, we report the design of the new H0 branch duct and the study results with the test ducts.

TUPS017

The LHC Experimental Beam Pipe Neon Venting, Pumping and Conditioning

injection, vacuum, ion, monitoring

1557

V. Baglin, G. Bregliozzi, D. Calegari, J.M. Jimenez, G. Lanza, G. Schneider
CERN, Geneva, Switzerland

The experimental vacuum chambers of the four LHC experiments (ATLAS, CMS, LHCb and ALICE) are mechanically optimized in order to be transparent to particles. In order to grant their mechanical stability and to avoid any overstress, every time there was a request for detector opening or closing and for working in the vicinity of the vacuum chamber, the experimental beam vacuum chambers have been vented to atmospheric pressure. Since the LHC start up a safety procedure has been applied to mechanically secure the four experimental beam pipes during each long technical stop. Ultra-pure neon was used to preserve at best the NEG pumping efficiency. Up to now more than 15 neon injections and pump down have been performed without detecting any reduction of the NEG efficiency. This paper describes the Gas Injection System performances and the main points of the venting and pumping procedure. Details of the experimental beam pipe vacuum recovery and conditioning are presented for each of the four LHC experiments (ATLAS, CMS, LHCb and ALICE).

TUPS039

Reduction of Magnetic Interference on the Position Sensors of the LHC Collimators

simulation, radiation, dipole

1623

A. Masi, M. Lamberti, R. Losito, M. Martino
CERN, Geneva, Switzerland

The jaws of the LHC collimators have to be positioned with respect to the beam with an accuracy of 20 μm. On some collimators, installed in the LHC transfer lines from SPS, huge reading errors of several tens of micrometers have been observed on the Linear Variable Differential Transformer (LVDT) positioning sensors in synchronization with the variable magnetic field produced by the feed cables of the pulsed resistive dipoles of the transfer line. In this paper we introduce and describe in detail the problem, the model developed using FLUXTM for the simulation of the magnetic flux density generated by the current cables in the complex environment of an LHC transfer line, and the magnetic shielding we designed and implemented. Finally, we compare the results of simulations with experimental measurements taken during on-line pulsed magnets test campaigns.

TUPS045

IFMIF/EVEDA Beam Dump Shielding: Optimized Design of the Front Part

radiation, photon, neutron, diagnostics

1635

M. García, D. Lopez, A. Mayoral, F. Ogando, J. Sanz, P. Sauvan
UNED, Madrid, Spain
J.M. Arroyo, B. Brañas
CIEMAT, Madrid, Spain

The Beam Dump of the IFMIF/EVEDA accelerator prototype, designed to stop deuteron beam with energy up to 9 MeV and a maximum beam power of 1.12 MW, needs to fulfill radioprotection requirements. The deuteron beam collides with the beam stop and neutron and photon sources are produced. The objective of this paper is to design and justify the front part of the local shielding of the Beam Dump that complies with radiation limits for workers during beam-off phases. This shielding must allow unrestricted maintenance operations inside the vault, where the accelerator is located, after a reasonable cooling time after shutdown. In doing so, two main handicaps have been overcome. On one hand, the reliability of the traditionally used Monte Carlo codes such as MCNPX and PHITS has demonstrated to be very poor for deuteron transport at these low energies. In order to solve this lack, the MCUNED code using TENDL library is proposed to be used for deuteron transport and the prediction of the neutron and photon sources. On the other hand, the lack of space in the area dedicated to the last part of the accelerator demands a specially optimized shielding solution.

TUPS048

Equipment and Techniques for the Replacement of the ISIS Proton Beam to Target Window

target, radiation, proton, neutron

1638

S.D. Gallimore, S.J.S. Jago
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

The ISIS Spallation Neutron Source has been in operation at the Rutherford Appleton Laboratory for over 25 years. Much of the original equipment installed during the construction of the facility is still in operation. The window separating the proton beam transfer line from the neutron target is a key component in the accelerator complex. During the operational life of the Beam Entry Window it has absorbed a considerable amount of energy deposited from the proton beam as it passes from the accelerator vacuum to the target area. Due to the difficulties in accessing and handling the window assembly, a decision was made to replace this component in a planned maintenance period. This paper describes the specialist remote handling equipment and techniques that were developed during the 3 year build up to the removal and replacement of the of the highly active Beam Entry Window.

TUPS053

A Target Magnet System for a Muon Collider and Neutrino Factory

target, radiation, factory, collider

1650

H.G. Kirk
BNL, Upton, Long Island, New York, USA
V.B. Graves
ORNL, Oak Ridge, Tennessee, USA
K.T. McDonald
PU, Princeton, New Jersey, USA
N. Souchlas, R.J. Weggel
Particle Beam Lasers, Inc., Northridge, California, USA

Funding: This work is supported in part by the US DOE Contract NO. DE-AC02-98CH10886.
The target system envisioned for a Muon Collider or Neutrino Factory includes a 20-T solenoid field surrounding a mercury jet target with the field tapering to 1.5 T 15 m downstream of the target. A principal challenge is to shield the superconducting magnets from the radiation issuing from the 4-MW proton beam impacting the target. We describe a solution which will deliver the desired field while being capable of tolerating the intense radiation environment surrounding the target.

TUPS059

SPS WANF Dismantling: A Large Scale-Decommissioning Project at CERN

radiation, target, feedback, ion

1668

S. Evrard, Y. Algoet, N. Conan, D. DePaoli, I. Efthymiopoulos, S. Fumey, H. Gaillard, J.L. Grenard, D. Grenier, A. Pardons, E. Paulat, Y.D.R. Seraphin, M. Tavlet, C. Theis, H. Vincke
CERN, Geneva, Switzerland

The operation of the SPS (Super Proton Synchrotron) West Area Neutrino Facility (WANF) was halted in 1998. In 2010 a large scale-decommissioning of this facility was conducted. Besides CERN’s commitment to remove non-operational facilities, the additional motivation was the use of the installation (underground tunnels and available infrastructure) for the new HiRadMat facility, which is designed to study the impact of high-intensity pulsed beams on accelerator components and materials. The removal of 800 tons of radioactive equipment and the waste management according to the ALARA (As Low As Reasonably Achievable) principles were two major challenges. This paper describes the solutions implemented and the lessons learnt confirming that the decommissioning phase of a particle accelerator must be carefully studied as from the design stage.

WEPC108

CSR Impedance for an Ultrarelativistic Beam moving in a Curved Trajectory

impedance, vacuum, resonance, radiation

2268

D.M. Zhou, K. Ohmi, K. Oide
KEK, Ibaraki, Japan

A dedicated computer code, CSRZ, has been developed to calculate the coherent synchrotron radiation (CSR) impedance for an ultrarelativistic beam moving in a curved trajectory. Following the pioneering work of T. Agoh and K. Yokoya*, the code solves the parabolic equation in the frequency domain in a curvilinear coordinate system. The beam is assumed to move along a vacuum chamber which has a uniform rectangular cross section but with variable bending radius. Using this code, we did investigations in calculating the longitudinal CSR impedance of a single and a series of bending magnets. The calculation results indicate that the shielding effect due to outer chamber wall can be well explained by a simple optical approximation model at high frequencies. The CSR fields reflected by the outer wall may interfere with each other in a long bending magnet and lead to sharp narrow peaks in the CSR impedance.
* T. Agoh and K. Yokoya, Phys. Rev. ST Accel. Beams, 7(5):054403 (2004).

WEPC165

Monte Carlo Simulation of the Total Dose Distribution around the 12 MeV UPC Race-track Microtron and Radiation Shielding Calculations

radiation, simulation, target, beam-losses

2370

C. de la Fuente, M.A. Duch, Yu.A. Kubyshin
UPC, Barcelona, Spain
V.I. Shvedunov
MSU, Moscow, Russia

The Technical University of Catalonia is building a miniature 12 MeV electron race-track microtron for medical applications. In the paper we study the leakage radiation caused by beam losses inside the accelerator head, as well as the bremstrahlung radiation produced by the primary beam in the commissioning setting. Results of Monte Carlo simulations using the PENELOPE code are presented and two shielding schemes, global and local, are studied. The obtained shielding parameters are compared with estimates based on international recommendations of the radiation safety standards.

WEPC166

Licensing and Safety Issues of the ESS Accelerator

radiation, target, beam-losses, neutron

2373

P.E.T. Jacobsson, M. Brandin, D. Ene, T. Hansson
ESS, Lund, Sweden

The licensing process for the European Spallation Source (ESS) has started up. The process includes both an application to the Environmental Court in Sweden as well as the application towards the Swedish Radiation Protection Authority (SSM). The applications will be based on an Environmental Impact Assessment EIA) and a Safety Analysis Report (SAR). One important step has been to define which regulations that apply for ESS. ESS has also set up General Safety Objectives (GSO). Based on the GSO and the legal requirements, the process design of the whole ESS facility is ongoing. This paper will focus upon the radiation safety issues related to the accelerator. This includes items as radiation shielding, personal protection system and operation emissions. Analyses and calculations, based on a preliminary design and layout of the ESS accelerator, will be presented. Discussion is made on issues like shielding material, shielding design and analysis models.

WEPO006

Suppression of Leakage Fields from DC Magnets in J-PARC 3 GeV RCS

beam-losses, extraction, septum, vacuum

2412

M. Yoshimoto, H. Harada, N. Hayashi, H. Hotchi, M. Kinsho, P.K. Saha, K. Yamamoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

In the J-PARC 3 GeV RCS, we found that DC leakage fields from the extraction beam line significantly affected the beam. For this issue, we installed additional shields and got the 40% reduction of the DC leakage field. Thus the circulating beam loss was successfully reduced. In this presentation, we report the detail of the shield structure and the results of the beam studies.

THPC146

The Radiated EMI Isolation for TPS Kicker Magnet*

kicker, radiation, electromagnetic-fields, controls

3227

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

Electromagnetic interference is a critical problem for electronic equipment, especially for those sophisticated measuring sensors using in TLS. Therefore, lots of efforts have been made to isolate the EM noise from the kicker magnets. In this article, different thicknesses of aluminum chambers are applied to block the radiated EM noise. Furthermore, the different widths of slits simulate the necessary openings on kicker assembly. According to the results of small-scale experiment, some parameters are obtained to design the enclosure of kicker magnet. Compared the results with the data from the original scale kicker, these parameters provide a believable guideline in the beginning of design status.

THPC186

Heat Load for the APS Superconducting Undulator

photon, radiation, simulation, undulator

3332

L.E. Boon, A.F. Garfinkel
Purdue University, West Lafayette, Indiana, USA
K.C. Harkay
ANL, Argonne, USA

Funding: Work supported by U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
The APS Upgrade calls for the development and commissioning of a superconducting undulator (SCU) at the Advanced Photon Source (APS), a 7-GeV electron synchrotron. The first SCU will be installed in June 2012. Until then, simulations such as SYNRAD3D will be used to understand and reduce the heat load on the cryo-system from primary and secondary photons. Current calculations predict that primary photons will distribute 0.5W/m on the chamber walls of the cryostat. SYNRAD3D will be used to calculate the ratio of primary and secondary photons to calculate the heat load due to secondary photons. Previous simulations were of only one sector of the APS accelerator. Simulated here are multiple sectors, to include photons back scattered from downstream photon absorbers.

THPS055

Controlling Beamloss at Injection into the LHC

injection, beam-losses, emittance, kicker

3553

B. Goddard, F. Alessio, W. Bartmann, P. Baudrenghien, V. Boccone, C. Bracco, M. Brugger, K. Cornelis, B. Dehning, A. Di Mauro, L.N. Drosdal, E.B. Holzer, W. Höfle, R. Jacobsson, V. Kain, M. Meddahi, V. Mertens, A. Nordt, J.A. Uythoven, D. Valuch, S. Weisz, E.N. del Busto
CERN, Geneva, Switzerland
R. Appleby
UMAN, Manchester, United Kingdom

Losses at injection into the superconducting LHC can adversely affect the machine performance in several important ways. The high injected beam intensity and energy mean that precautions must be taken against damage and quenches, including collimators placed close to the beam in the injection regions. Clean injection is essential, to avoid spurious signals on the sensitive beam loss monitoring system which will trigger beam dumps. In addition, the use of the two injection insertions to house downstream high energy physics experiments brings constraints on permitted beam loss levels. In this paper the sources of injection beam loss are discussed together with the contributing factors and various issues experienced in the first full year of LHC operation. Simulations are compared with measurement, and the implemented and planned mitigation measures and diagnostic improvements are described. An outlook for future LHC operation is given.

THPS065

Upgraded X-band 950 KeV Linac X-ray Source for On-site Inspection at Petrochemical Complex

linac, status, coupling, site

3574

M. Jin, K. Demachi, K. Dobashi, H.F. Jin, T. Natsui, M. Uesaka
The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan
J. Kusano, N. Nakamura, M. Yamamoto
Accuthera Inc., Kawasaki, Kanagawa, Japan
E. Tanabe
AET, Kawasaki-City, Japan

Abstract―Our portable X-band (9.3GHz) 950KeV linac has been successfully upgraded. The problems of RF power oscillation, beam current oscillation and reduction and finally lack of X-ray intensity were solved by replacing the axial coupling cavities with the side-coupled ones. Designed X-ray dose rate of 0.05 Sv/min@1m is going to be achieved. Length of the accelerating tube is reduced to less than 25 cm. X-ray source part with the local radiation shielding is connected by the flexible waveguide with the box of the 300 kW　magnetron and cooling unit. The total system consists of the three suit-case-size units, the last of which is one for the electric power supply. Even on-line dynamic transmission imaging is available by using the high intensity X-ray camera. Demonstration of the measurement of wall thinning of metal pipes with thick thermal shielding is under way. Updated measurement results will be presented. KEYWORDS: portable X-band linac X-ray source, on-site high energy X-ray inspection, petrochemical complex

THPS068

A Proton Therapy Test Facility: The Radiation Protection Design

proton, radiation, neutron, simulation

3583

S. Sandri, M.C. Carpanese, G. Ottaviano, L. Picardi, C. Poggi, C. Ronsivalle
ENEA C.R. Frascati, Frascati (Roma), Italy

A proton therapy test facility is planned to be sited in the Frascati ENEA Research Center, in Italy. A 30 m long, 3 m wide bunker has to be designed to host a proton linear accelerator with a low beam current, lower than 10 nA in average, and an energy up to 150 MeV. The accelerator will be part of the TOP-IMPLART project for deep tumors treatment. The design of the 150 MeV accelerator is under study and the radiation protection solutions are considered in this phase. The linear accelerator has some safety advantages if compared to cyclotrons and synchrotrons. It can be easily housed in the long, narrow tunnel. The main radiation losses during the acceleration process occur below 20 MeV, with a low neutron production. As a consequence the barriers needed should be substantially lighter than the one used for other types of machines. In the paper the simulation models and the calculation performed with Monte Carlo codes are described. The related results are presented together with those assessed by using published experimental data. Considerations about workers and population protection are issued in the conclusions.

FRXAA01

Theory of Microwave Instability and Coherent Synchrotron Radiation in Electron Storage Rings

impedance, synchrotron, electron, storage-ring

3774

Y. Cai
SLAC, Menlo Park, California, USA

Funding: This work was supported by Department of Energy Contract No. DE-AC02-76SF00515.
Bursting of coherent synchrotron radiation has been observed and in fact used to generate THz radiation in many electron storage rings. In order to understand and control the bursting, we return to the study of the microwave instability. In this talk, we will report on the theoretical understanding, including recent developments, of the microwave instability in electron storage rings. The historical progress of the theories will be surveyed, starting from the dispersion relation of coasting beams, to the work of Sacherer on a bunched beam, and ending with the Oide and Yokoya method of discretization. This theoretical survey will be supplemented with key experimental results over the years. Finally, we will describe the recent theoretical development of utilizing the Laguerre polynomials in the presence of potential-well distortion. This self-consistent method will be applied to study the microwave instability driven by commonly known impedances, including that of coherent synchrotron radiation.

Slides FRXAA01 [0.948 MB]