2011 Particle Accelerator Conference - List of Keywords (shielding)

Paper	Title	Other Keywords	Page
MOP018	The Impact of Beam Emittance on BSM-Physics Discovery Potential at a Muon Collider	collider, background, electron, luminosity	142
	D. Greenwald, A. Caldwell MPI-P, München, Germany
	A muon collider would allow for high precision probing of the multi-TeV energy regime and the potential discovery of new physics. Background radiation from electrons from the decay of muons interacting with the beam pipes near the interaction point (IP) places limitations on the design of a muon-collider detector. In particular, conical shielding extending out from the IP along the outside of the beam pipes prevents detection of particles at small angles to the beam line. For a given luminosity, bunches with smaller emittances will have fewer muons and therefore smaller background levels, allowing for shielding with shallower angles. The angular-acceptance dependence of the discovery potential for Kaluza-Klein excitations of the standard model particles is presented as a motivation for improved beam-cooling techniques that can achieve high luminosities with small bunch populations.

MOP067	Vlasov and PIC Simulations of a Modulator Section for Coherent Electron Cooling	ion, electron, simulation, plasma	235
	G.I. Bell, D.L. Bruhwiler, I.V. Pogorelov, B.T. Schwartz Tech-X, Boulder, Colorado, USA Y. Hao, V. Litvinenko, G. Wang BNL, Upton, Long Island, New York, USA
	Funding: This work is supported by the US DOE Office of Science, Office of Nuclear Physics, grant numbers DE-SC0000835 and DE-FC02-07ER41499. Resources of NERSC were used under contract No. DE-AC02-05CH11231. Next generation ion colliders will require effective cooling of high-energy hadron beams. Coherent electron cooling (CEC) can in principle cool relativistic hadron beams on orders-of-magnitude shorter time scales than other techniques. We present Vlasov-Poisson and delta-f particle-in-cell (PIC) simulations of a CEC modulator section. These simulations correctly capture the subtle time and space evolution of the density and velocity wake imprinted on the electron distribution via anisotropic Debye shielding of a drifting ion. We consider 1D and 2D reduced versions of the problem, and compare the exact solutions of Wang and Blaskiewicz with Vlasov-Poisson and delta-f PIC simulations. We also consider interactions under non-ideal conditions where there is a density gradient in the electron distribution, and present simulations of the ion wake. * V.N. Litvinenko and Y.S. Derbenev, Phys. Rev. Lett. 102, 114801 (2009).

MOP192	NSLS-II BPM System Protection from Rogue Mode Coupling	vacuum, multipole, radiation, synchrotron	450
	A. Blednykh, B. Bacha, A. Borrelli, M.J. Ferreira, C. Hetzel, H.-C. Hseuh, B.N. Kosciuk, S. Krinsky, O. Singh, K. Vetter BNL, Upton, Long Island, New York, USA
	Funding: Work supported by DOE contract DE-AC02-98CH10886 Rogue mode RF shielding has been successfully designed and implemented into the production multipole vacuum chambers. In order to avoid systematic errors in the NSLS-II BPM system we introduced frequency shift of HOM's by using RF metal shielding located in the antechamber slot of each multipole vacuum chamber. To satisfy the pumping requirement the face of the shielding has been perforated with roughly 50 percent transparency. It stays clear of synchrotron radiation in each chamber.

MOP232	LANSCE-R Wire-Scanner Analog Frontend Electronics (AFE)	controls, coupling, electromagnetic-fields, monitoring	542
	M.E. Gruchalla URS, Albuquerque, New Mexico, USA P. Chacon, J.D. Gilpatrick, D. Martinez, J.D. Sedillo LANL, Los Alamos, New Mexico, USA
	Funding: U.S. Department of Energy. A new AFE is being developed for the new LANSCE-R wire-scanner systems. The new AFE is implemented in a National Instruments cRIO module installed a BiRa 4U BiRIO cRIO chassis specifically designed to accommodate the cRIO crate and all the wire-scanner interface, control and motor-drive electronics. A single AFE module provides interface to both X and Y wire sensors using true DC coupled transimpedance amplifiers providing collection of the wire charge signals, real-time wire integrity verification using the normal data-acquisition system, and wire bias of 0V to ±50V. The AFE system is designed to accommodate comparatively long macropulses (>1ms) with high PRF (>120Hz) without the need to provide timing signals. The basic AFE bandwidth is flat from true DC to 50kHz with a true first-order pole at 50kHz. Numeric integration in the cRIO FPGA provides real-time pulse-to-pulse numeric integration of the AFE signal to compute the total charge collected in each macropulse. This method of charge collection eliminates the need to provide synchronization signals to the wire-scanner AFE while providing the capability to accurately record the charge from long macropulses at high PRF.

MOP274	Beam Loss Monitors for NSLS-II Storage Ring	electron, injection, radiation, dipole	621
	S.L. Kramer, P. Cameron BNL, Upton, Long Island, New York, USA
	Funding: Work supported by U.S. DOE, Contract No.DE-AC02-98CH10886 The shielding for the NSLS-II storage ring will provide adequate protection for the full injected beam losses in two periods of the ring around the injection point, but the remainder of the ring is shielded for lower losses of <10% top-off injection beam current. This will require a system to insure that beam losses do not exceed these levels for a period of time that could cause excessive radiation exposure outside the shield walls. This beam Loss Control and Monitoring system will have beam loss monitors that will measure where the beam charge is lost around the ring, to warn operators if losses approach the design limits. In order to measure the charge loss quantitatively, we propose measuring the electron component of the shower as beam electrons hit the vacuum chamber wall. This will be done using the Cerenkov light as charged particles transit an ultra-pure fused silica rod placed close to the inner edge of the VC. The length of rod will collect the light from many charged particles of the spread out shower resulting from the small glancing angle of the lost beam particles to the VC wall. The design and measurements results of the prototype Cerenkov BLM will be presented.

MOP275	Beam Loss Control for the NSLS-II Storage Ring	injection, controls, dipole, beam-losses	624
	S.L. Kramer, J. Choi BNL, Upton, Long Island, New York, USA
	Funding: Work supported by U.S. DOE, Contract No.DE-AC02-98CH10886 The shielding design for the NSLS-II storage ring is designed for the full injected beam losses in two periods of the ring around the injection point, but for the remainder of the ring its shielded for <10% top-off injection beam. This will require a system to insure that beam losses do not exceed these levels for time sufficient to cause excessive radiation exposure outside the shield walls. This beam Loss Control and Monitoring (LCM) system will control the beam losses to the more heavily shielded injection region while monitoring the losses outside this region. To achieve this scrapers are installed in the injection region to intercept beam particles that might be lost outside this region. The scrapers will be thin (< 1Xrad) that will allow low energy electrons to penetrate and the subsequent dipole will separate them from the stored beam. These thin scrapers will reduce the radiation from the scraper compared to thicker scrapers. The dipole will provide significant local shielding for particles that hit inside the gap and a source for the loss monitor system that will measure the amount of beam lost in the injection region. * Beam Loss Monitors for NSLS-II Storage Ring, S.L. Kramer & P. Cameron, these proceedings

TUP003	Beam Stop of Spiral2 Facility: Activation and Residual Dose Rate Calculations	neutron, simulation, photon, factory	811
	A. Mayoral, M. García, D. López, F. Ogando, J. Sanz, P. Sauvan UNED, Madrid, Spain
	Funding: SPIRAL 2 Preparatory Phase. European Strategy Forum on Research Infrastructures. Seventh Framework Programme Ref 212692 The Spanish Ministery of Science and Innovation. Project ENE2009-07572 SPIRAL2 facility is expected to produce 5mA of deuterons at 40 MeV. A beam dump device (BD) has been designed to stop the beam. In this paper we assess the residual dose rates (RDR) in the BD room during beam-off phases. MCNPX was used to deal with deuterons transport and production and transport of secondary neutrons. Deuteron and neutron induced activation were computed using ACAB and EAF2007. Decay gammas were transported using MCNPX to compute RDR. Dose rates at cooling times up to one year are presented, showing that it is mainly due to BD copper induced activation. The uncertainties in the results can be attributed to: i) the reliability of the d-Cu activation cross sections reactions, ii) the computational approach used to assess the neutron source. The troublesome radioisotopes from d-Cu and their formation reactions were identified. EAF2007 cross sections for these reactions were compared with the available experimental data. Regarding the computational approach to determine the neutron source from d-Cu interactions two options were used: i) built-in nuclear models of MCNPX, ii) TENDL and MCUNED. The available experimental data were used for benchmarking. J. Sanz et al. ACAB. User’s manual NEA-1839 (2009) A.J. Koning et al. TENDL2008 http://www.talys.eu/tendl-2008/ * P.Sauvan et al. Nucl. Instr.and Meth. A 614 (2010)3 323-330.

TUP033	Engineering Design of Vertical Test Stand Cryostat	vacuum, cavity, radiation, instrumentation	874
	S.K. Suhane, S. Das, P.D. Gupta, S.C. Joshi, P.K. Kush, S. Raghvendra, N.K. Sharma RRCAT, Indore (M.P.), India R.H. Carcagno, C.M. Ginsburg, C.S. Mishra, J.P. Ozelis, R. Rabehl, C. Sylvester Fermilab, Batavia, USA V.C. Sahni Homi Bhbha National Institute (HBNI), DAE, Mumbai, India
	Under Indian Institutions and Fermilab collaboration Raja Ramanna Centre for Advanced Technology and Fermi Lab are jointly developing 2K Vertical Test Stand (VTS) cryostats for testing SCRF cavities. The VTS cryostat has been designed for a large testing aperture of 34 inches for testing of 325 MHz Spoke resonators, 650 MHz and 1.3 GHz multi-cell SCRF cavities for Project-X at FNAL and for VTS facility at RRCAT. VTS cryostat comprises of liquid helium (LHe) vessel with internal magnetic shield, top insert plate equipped with cavity support stand and radiation shield, liquid nitrogen (LN2) shield and vacuum vessel with external magnetic shield. . The engineering design and analysis of VTS cryostat has been carried out using ASME B&PV code and FEA. Design of internal and external magnetic shields was performed to limit the magnetic field inside LHe vessel, at the cavity surface <10 mG. Thermal analysis for LN2 shield has been performed to check the effectiveness of LN2 cooling.

TUP071	High Power Tests of Dressed Superconducting 1.3 GHz RF Cavities	cavity, cryomodule, resonance, higher-order-mode	949
	A. Hocker, E.R. Harms, A. Lunin, A.I. Sukhanov Fermilab, Batavia, USA
	Funding: U.S. Department of Energy, Contract No. DE-AC02-07CH11359 A single-cavity test cryostat is used to conduct pulsed high power RF tests of superconducting 1.3 GHz RF cavities at 2 K. The cavities under test are welded inside individual helium vessels and are outfitted (“dressed”) with a fundamental power coupler, higher-order mode couplers, magnetic shielding, a blade tuner, and piezoelectric tuners. The cavity performance is evaluated in terms of accelerating gradient, unloaded quality factor, and field emission, and the functionality of the auxiliary components is verified. Test results from the first set of dressed cavities are presented here.

TUP102	Cryogenic RF Material Testing at SLAC	cavity, niobium, cryogenics, factory	1030
	J. Guo, D.W. Martin, S.G. Tantawi, C. Yoneda SLAC, Menlo Park, California, USA
	Funding: The work is supported by the US Department of Energy We have been developing an X-band cryogenic RF material testing system since 2005. By measuring the Q of a hemispherical cavity with the material sample at is flat interchangeable bottom, the system is capable to characterize the surface resistance of different materials at the temperature of 3-300K, as well as the quenching RF magnetic field of the superconducting samples at different temperatures. Using a SLAC X-band 50 MW klystron, the system can measure the quenching H-field of up to 300mT under current setup, with the possibility of further enhancement by changing the RF distribution configuration.

TUP179	Energy Deposition within Superconducting Coils of a 4 MW Target Station	target, neutron, simulation, factory	1166
	X.P. Ding UCLA, Los Angeles, California, USA J.J. Back University of Warwick, Coventry, United Kingdom R.C. Fernow, H.G. Kirk, N. Souchlas BNL, Upton, Long Island, New York, USA K.T. McDonald PU, Princeton, New Jersey, USA R.J. Weggel Particle Beam Lasers, Inc., Northridge, California, USA
	Funding: Work Supported by the United States Department of Energy, Contract No. DE-AC02-98CH10886. A study of energy deposition within superconducting coils of a 4 MW target station for a neutrino factory or muon collider is presented. Using the MARS code, we simulate the energy deposition within the environment surrounding the target. The radiation is produced by interactions of intense proton beams with a free liquid mercury jet. We study the influence of different shielding materials and shielding configurations on the energy deposition in the superconducting coils of the target/capture system. We also examine energy depositions for alternative configurations that allow more space for shielding, thus providing more protection for the superconducting coils.

TUP224	Cryogenic Vertical Test Facility for the SRF Cavities at BNL	vacuum, cryogenics, SRF, radiation	1238
	R. Than, I. Ben-Zvi, A. Burrill, M.C. Grau, D.L. Lederle, C.J. Liaw, G.T. McIntyre, D. Pate, R. Porqueddu, T.N. Tallerico, J.E. Tuozzolo BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy A vertical facility has been constructed to test SRF cavities and can be utilized for other use. The liquid helium volume for the large vertical dewar is approximate 84 inches tall by 40 inches diameter with a working clear inner diameter of 38 inch with the inner cold magnetic shield system installed. For radiation enclosure, the test dewar is situated inside a concrete block structure. The structure is above ground and is accessible from the top, and has a retractable concrete roof. A second radiation concrete facility, with ground level access via a labyrinth is also available for testing of smaller cavities in 2 smaller dewars.

WEP107	CSR Shielding Experiment	wakefield, dipole, linac, electron	1677
	V. Yakimenko, A.V. Fedotov, M.G. Fedurin, D. Kayran BNL, Upton, Long Island, New York, USA V. Litvinenko Stony Brook University, Stony Brook, USA P. Muggli USC, Los Angeles, California, USA
	It is well known that the emission of coherent synchrotron radiation (CSR) in a dipole magnets leads to increase in beam energy spread and emittance. At the Brookhaven National Laboratory Accelerator Test Facility (ATF) we study the suppression of CSR emission affect on electron beam in a dipole magnet by two vertically spaced conducting plates. The gap between the plates is controlled by four actuators and could be varied from 0 to 14 mm. Our experimental results show that closing the plates significantly reduces both the beam energy loss and CSR-induced beam energy spread. In this paper we present selected results of the experiment and compare then with rigorous analytical theory.

WEP248	Overview of the LBNE Neutrino Beam	target, proton, simulation, remote-handling	1948
	C.D. Moore, Y. He, P. Hurh, J. Hylen, B.G. Lundberg, M.W. McGee, J.R. Misek, N.V. Mokhov, V. Papadimitriou, R.K. Plunkett, R.P. Schultz, G. Velev, K.E. Williams, R.M. Zwaska Fermilab, Batavia, USA
	Funding: Work supported by Fermi Research Alliance, LLC, under contract DE-AC02-07CH11359 with the U.S. Department of Energy. The Long Baseline Neutrino Experiment (LBNE) will utilize a neutrino beamline facility located at Fermilab. The facility will aim a beam of neutrinos toward a detector placed at the Deep Underground Science and Engineering Laboratory (DUSEL) in South Dakota. The neutrinos are produced in a three step process. First, protons from the Main Injector hit a solid target and produce mesons. Then, the charged mesons are focused by a set of focusing horns into the decay pipe, towards the far detector. Finally, the mesons that enter the decay pipe decay into neutrinos. The parameters of the facility were determined by an amalgam of the physics goals, the Monte Carlo modeling of the facility, and the experience gained by operating the NuMI facility at Fermilab. The initial beam power is expected to be ~700 kW, however some of the parameters were chosen to be able to deal with a beam power of 2.3 MW.

WEP297	A Conceptual Design of the 2+ MW LBNE Beam Absorber	proton, simulation, target, hadron	2041
	G. Velev, S.C. Childress, P. Hurh, J. Hylen, A.V. Makarov, N.V. Mokhov, C.D. Moore, I. Novitski Fermilab, Batavia, USA
	Funding: This work is supported by the U.S. Department of Energy. The Long Baseline Neutrino Experiment (LBNE) will utilize a neutrino beamline facility located at Fermilab. The facility will aim a beam of neutrinos, produced by 60-120 GeV protons from the Fermilab Main Injector, toward a detector placed at the Deep Underground Science and Engineering Laboratory (DUSEL) in South Dakota. Secondary particles that do not decay into muons and neutrinos as well as any residual proton beam must be stopped at the end of the decay region to reduce noise/damage in the downstream muon monitors and reduce activation in the surrounding rock. This goal is achieved by placing an absorber structure at the end of the decay region. The requirements and conceptual design of such an absorber, capable of operating at 2+ MW primary proton beam power, is described.

THP053	The New Approximation of Dose Attenuation Curve in Concrete	neutron, ion, heavy-ion, target	2217
	M. Petrichenkov, V.Ya. Chudaev BINP SB RAS, Novosibirsk, Russia
	The analytical approach in shielding calculations is simple and fast method for quick estimations. But it provides less accuracy than Monte-Carlo one. Often the exponential attenuation of dose in shielding is considered. But also it is necessary to take into account the dose increase in the first layers of shielding due to initial accumulation of neutrons. The new approximation of dose attenuation curve in concrete is offered for quick analytical estimations of shielding of hadron accelerators. It allows to make fast estimation of shielding thickness enough correctly.

THP088	Beam Induced Detector Backgrounds at a Muon Collider	collider, background, electron, neutron	2300
	S.A. Kahn, M.A.C. Cummings, T.J. Roberts Muons, Inc, Batavia, USA D. Hedin, A.O. Morris Northern Illinois University, DeKalb, Illinois, USA J.F. Kozminski Lewis University, Romeoville, Illinois, USA
	Funding: Supported in part by SBIR Grant DE-SC0005447 Muon colliders are considered to be an important future energy frontier accelerator. It is possible to build a large muon collider as a circular machine, even at multi-TeV energies, due to the greatly reduced synchrotron radiation expected from muons. In addition to the same physics processes present in an electron collider, a muon collider will have the potential to produce s-channel resonances such as the various Higgs states at an enhanced rate. For a muon collider with 750 GeV/c mu+ and mu- with 10¹² mu per bunch we would expect 4.3x10⁵ muon decays per meter. These muon decays will produce very energetic off momentum electrons that can produce detector backgrounds that can affect the physics. These backgrounds include electrons from muon decays, synchrotron radiation from the decay electrons, hadrons produced by photo-nuclear interactions, coherent and incoherent beam-beam pair production and Bethe-Heitler muon production. In this paper we will discuss these processes and calculate particle fluxes into the detector volume from these background processes.

THP110	Front End Energy Deposition and Collimation Studies for IDS-NF	proton, factory, target, beam-losses	2333
	C.T. Rogers STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom D.V. Neuffer Fermilab, Batavia, USA P. Snopok IIT, Chicago, Illinois, USA
	Funding: Work supported by DOE, STFC. The function of the Neutrino Factory front end is to reduce the energy spread and size of the muon beam to a manageable level that will allow reasonable throughput to subsequent system components. Since the Neutrino Factory is a tertiary machine (protons to pions to muons), there is an issue of large background from the pion-producing target. The implications of energy deposition in the front end lattice for the Neutrino Factory are addressed. Several approaches to mitigating the effect are proposed and discussed, including proton absorbers, chicanes, beam collimation, and shielding.

THP225	Characterization and Suppression of the Electromagnetic Interference Induced Phase Shift in the JLab FEL Photo – Injector Advanced Drive Laser System	FEL, laser, controls, electron	2546
	F.G. Wilson, D.W. Sexton, S. Zhang JLAB, Newport News, Virginia, USA
	The new drive laser for the photo-cathode gun used in the JLab FEL facility had been experiencing various phase shifts on the order of tens of degrees (>20° at 1497 MHz or >40ps) when changing the Advanced Drive Laser (ADL) micro-pulse frequencies. These phase shifts introduce multiple complications when trying to setup the accelerator for operation, ultimately inhibiting the robustness and overall performance of the FEL. Through rigorous phase measurements and systematic characterizations, we discovered the problems could be attributed to EMI coupling into the ADL phase control loop system, and subsequently resolved the issue of phase shift to within tenths of a degree (<0.5° at 1497 MHz or <1ps). The diagnostic method developed and the knowledge gained through the entire process will prove to be invaluable for future designs of similar systems.

Paper

Title

Other Keywords

Page

MOP018

The Impact of Beam Emittance on BSM-Physics Discovery Potential at a Muon Collider

collider, background, electron, luminosity

142

D. Greenwald, A. Caldwell
MPI-P, München, Germany

A muon collider would allow for high precision probing of the multi-TeV energy regime and the potential discovery of new physics. Background radiation from electrons from the decay of muons interacting with the beam pipes near the interaction point (IP) places limitations on the design of a muon-collider detector. In particular, conical shielding extending out from the IP along the outside of the beam pipes prevents detection of particles at small angles to the beam line. For a given luminosity, bunches with smaller emittances will have fewer muons and therefore smaller background levels, allowing for shielding with shallower angles. The angular-acceptance dependence of the discovery potential for Kaluza-Klein excitations of the standard model particles is presented as a motivation for improved beam-cooling techniques that can achieve high luminosities with small bunch populations.

MOP067

Vlasov and PIC Simulations of a Modulator Section for Coherent Electron Cooling

ion, electron, simulation, plasma

235

G.I. Bell, D.L. Bruhwiler, I.V. Pogorelov, B.T. Schwartz
Tech-X, Boulder, Colorado, USA
Y. Hao, V. Litvinenko, G. Wang
BNL, Upton, Long Island, New York, USA

Funding: This work is supported by the US DOE Office of Science, Office of Nuclear Physics, grant numbers DE-SC0000835 and DE-FC02-07ER41499. Resources of NERSC were used under contract No. DE-AC02-05CH11231.
Next generation ion colliders will require effective cooling of high-energy hadron beams. Coherent electron cooling (CEC) can in principle cool relativistic hadron beams on orders-of-magnitude shorter time scales than other techniques. We present Vlasov-Poisson and delta-f particle-in-cell (PIC) simulations of a CEC modulator section. These simulations correctly capture the subtle time and space evolution of the density and velocity wake imprinted on the electron distribution via anisotropic Debye shielding of a drifting ion. We consider 1D and 2D reduced versions of the problem, and compare the exact solutions of Wang and Blaskiewicz with Vlasov-Poisson and delta-f PIC simulations. We also consider interactions under non-ideal conditions where there is a density gradient in the electron distribution, and present simulations of the ion wake.
* V.N. Litvinenko and Y.S. Derbenev, Phys. Rev. Lett. 102, 114801 (2009).

MOP192

NSLS-II BPM System Protection from Rogue Mode Coupling

vacuum, multipole, radiation, synchrotron

450

A. Blednykh, B. Bacha, A. Borrelli, M.J. Ferreira, C. Hetzel, H.-C. Hseuh, B.N. Kosciuk, S. Krinsky, O. Singh, K. Vetter
BNL, Upton, Long Island, New York, USA

Funding: Work supported by DOE contract DE-AC02-98CH10886
Rogue mode RF shielding has been successfully designed and implemented into the production multipole vacuum chambers. In order to avoid systematic errors in the NSLS-II BPM system we introduced frequency shift of HOM's by using RF metal shielding located in the antechamber slot of each multipole vacuum chamber. To satisfy the pumping requirement the face of the shielding has been perforated with roughly 50 percent transparency. It stays clear of synchrotron radiation in each chamber.

MOP232

LANSCE-R Wire-Scanner Analog Frontend Electronics (AFE)

controls, coupling, electromagnetic-fields, monitoring

542

M.E. Gruchalla
URS, Albuquerque, New Mexico, USA
P. Chacon, J.D. Gilpatrick, D. Martinez, J.D. Sedillo
LANL, Los Alamos, New Mexico, USA

Funding: U.S. Department of Energy.
A new AFE is being developed for the new LANSCE-R wire-scanner systems. The new AFE is implemented in a National Instruments cRIO module installed a BiRa 4U BiRIO cRIO chassis specifically designed to accommodate the cRIO crate and all the wire-scanner interface, control and motor-drive electronics. A single AFE module provides interface to both X and Y wire sensors using true DC coupled transimpedance amplifiers providing collection of the wire charge signals, real-time wire integrity verification using the normal data-acquisition system, and wire bias of 0V to ±50V. The AFE system is designed to accommodate comparatively long macropulses (>1ms) with high PRF (>120Hz) without the need to provide timing signals. The basic AFE bandwidth is flat from true DC to 50kHz with a true first-order pole at 50kHz. Numeric integration in the cRIO FPGA provides real-time pulse-to-pulse numeric integration of the AFE signal to compute the total charge collected in each macropulse. This method of charge collection eliminates the need to provide synchronization signals to the wire-scanner AFE while providing the capability to accurately record the charge from long macropulses at high PRF.

MOP274

Beam Loss Monitors for NSLS-II Storage Ring

electron, injection, radiation, dipole

621

S.L. Kramer, P. Cameron
BNL, Upton, Long Island, New York, USA

Funding: Work supported by U.S. DOE, Contract No.DE-AC02-98CH10886
The shielding for the NSLS-II storage ring will provide adequate protection for the full injected beam losses in two periods of the ring around the injection point, but the remainder of the ring is shielded for lower losses of <10% top-off injection beam current. This will require a system to insure that beam losses do not exceed these levels for a period of time that could cause excessive radiation exposure outside the shield walls. This beam Loss Control and Monitoring system will have beam loss monitors that will measure where the beam charge is lost around the ring, to warn operators if losses approach the design limits. In order to measure the charge loss quantitatively, we propose measuring the electron component of the shower as beam electrons hit the vacuum chamber wall. This will be done using the Cerenkov light as charged particles transit an ultra-pure fused silica rod placed close to the inner edge of the VC. The length of rod will collect the light from many charged particles of the spread out shower resulting from the small glancing angle of the lost beam particles to the VC wall. The design and measurements results of the prototype Cerenkov BLM will be presented.

MOP275

Beam Loss Control for the NSLS-II Storage Ring

injection, controls, dipole, beam-losses

624

S.L. Kramer, J. Choi
BNL, Upton, Long Island, New York, USA

Funding: Work supported by U.S. DOE, Contract No.DE-AC02-98CH10886
The shielding design for the NSLS-II storage ring is designed for the full injected beam losses in two periods of the ring around the injection point, but for the remainder of the ring its shielded for <10% top-off injection beam. This will require a system to insure that beam losses do not exceed these levels for time sufficient to cause excessive radiation exposure outside the shield walls. This beam Loss Control and Monitoring (LCM) system will control the beam losses to the more heavily shielded injection region while monitoring the losses outside this region. To achieve this scrapers are installed in the injection region to intercept beam particles that might be lost outside this region. The scrapers will be thin (< 1Xrad) that will allow low energy electrons to penetrate and the subsequent dipole will separate them from the stored beam. These thin scrapers will reduce the radiation from the scraper compared to thicker scrapers. The dipole will provide significant local shielding for particles that hit inside the gap and a source for the loss monitor system that will measure the amount of beam lost in the injection region.
* Beam Loss Monitors for NSLS-II Storage Ring, S.L. Kramer & P. Cameron, these proceedings

TUP003

Beam Stop of Spiral2 Facility: Activation and Residual Dose Rate Calculations

neutron, simulation, photon, factory

811

A. Mayoral, M. García, D. López, F. Ogando, J. Sanz, P. Sauvan
UNED, Madrid, Spain

Funding: *SPIRAL 2 Preparatory Phase. European Strategy Forum on Research Infrastructures. Seventh Framework Programme Ref 212692 **The Spanish Ministery of Science and Innovation. Project ENE2009-07572
SPIRAL2 facility is expected to produce 5mA of deuterons at 40 MeV. A beam dump device (BD) has been designed to stop the beam. In this paper we assess the residual dose rates (RDR) in the BD room during beam-off phases. MCNPX was used to deal with deuterons transport and production and transport of secondary neutrons. Deuteron and neutron induced activation were computed using ACAB* and EAF2007. Decay gammas were transported using MCNPX to compute RDR. Dose rates at cooling times up to one year are presented, showing that it is mainly due to BD copper induced activation. The uncertainties in the results can be attributed to: i) the reliability of the d-Cu activation cross sections reactions, ii) the computational approach used to assess the neutron source. The troublesome radioisotopes from d-Cu and their formation reactions were identified. EAF2007 cross sections for these reactions were compared with the available experimental data. Regarding the computational approach to determine the neutron source from d-Cu interactions two options were used: i) built-in nuclear models of MCNPX, ii) TENDL** and MCUNED***. The available experimental data were used for benchmarking.
* J. Sanz et al. ACAB. User’s manual NEA-1839 (2009)
** A.J. Koning et al. TENDL2008 http://www.talys.eu/tendl-2008/
*** P.Sauvan et al. Nucl. Instr.and Meth. A 614 (2010)3 323-330.

TUP033

Engineering Design of Vertical Test Stand Cryostat

vacuum, cavity, radiation, instrumentation

874

S.K. Suhane, S. Das, P.D. Gupta, S.C. Joshi, P.K. Kush, S. Raghvendra, N.K. Sharma
RRCAT, Indore (M.P.), India
R.H. Carcagno, C.M. Ginsburg, C.S. Mishra, J.P. Ozelis, R. Rabehl, C. Sylvester
Fermilab, Batavia, USA
V.C. Sahni
Homi Bhbha National Institute (HBNI), DAE, Mumbai, India

Under Indian Institutions and Fermilab collaboration Raja Ramanna Centre for Advanced Technology and Fermi Lab are jointly developing 2K Vertical Test Stand (VTS) cryostats for testing SCRF cavities. The VTS cryostat has been designed for a large testing aperture of 34 inches for testing of 325 MHz Spoke resonators, 650 MHz and 1.3 GHz multi-cell SCRF cavities for Project-X at FNAL and for VTS facility at RRCAT. VTS cryostat comprises of liquid helium (LHe) vessel with internal magnetic shield, top insert plate equipped with cavity support stand and radiation shield, liquid nitrogen (LN2) shield and vacuum vessel with external magnetic shield. . The engineering design and analysis of VTS cryostat has been carried out using ASME B&PV code and FEA. Design of internal and external magnetic shields was performed to limit the magnetic field inside LHe vessel, at the cavity surface <10 mG. Thermal analysis for LN2 shield has been performed to check the effectiveness of LN2 cooling.

TUP071

High Power Tests of Dressed Superconducting 1.3 GHz RF Cavities

cavity, cryomodule, resonance, higher-order-mode

949

A. Hocker, E.R. Harms, A. Lunin, A.I. Sukhanov
Fermilab, Batavia, USA

Funding: U.S. Department of Energy, Contract No. DE-AC02-07CH11359
A single-cavity test cryostat is used to conduct pulsed high power RF tests of superconducting 1.3 GHz RF cavities at 2 K. The cavities under test are welded inside individual helium vessels and are outfitted (“dressed”) with a fundamental power coupler, higher-order mode couplers, magnetic shielding, a blade tuner, and piezoelectric tuners. The cavity performance is evaluated in terms of accelerating gradient, unloaded quality factor, and field emission, and the functionality of the auxiliary components is verified. Test results from the first set of dressed cavities are presented here.

TUP102

Cryogenic RF Material Testing at SLAC

cavity, niobium, cryogenics, factory

1030

J. Guo, D.W. Martin, S.G. Tantawi, C. Yoneda
SLAC, Menlo Park, California, USA

Funding: The work is supported by the US Department of Energy
We have been developing an X-band cryogenic RF material testing system since 2005. By measuring the Q of a hemispherical cavity with the material sample at is flat interchangeable bottom, the system is capable to characterize the surface resistance of different materials at the temperature of 3-300K, as well as the quenching RF magnetic field of the superconducting samples at different temperatures. Using a SLAC X-band 50 MW klystron, the system can measure the quenching H-field of up to 300mT under current setup, with the possibility of further enhancement by changing the RF distribution configuration.

TUP179

Energy Deposition within Superconducting Coils of a 4 MW Target Station

target, neutron, simulation, factory

1166

X.P. Ding
UCLA, Los Angeles, California, USA
J.J. Back
University of Warwick, Coventry, United Kingdom
R.C. Fernow, H.G. Kirk, N. Souchlas
BNL, Upton, Long Island, New York, USA
K.T. McDonald
PU, Princeton, New Jersey, USA
R.J. Weggel
Particle Beam Lasers, Inc., Northridge, California, USA

Funding: Work Supported by the United States Department of Energy, Contract No. DE-AC02-98CH10886.
A study of energy deposition within superconducting coils of a 4 MW target station for a neutrino factory or muon collider is presented. Using the MARS code, we simulate the energy deposition within the environment surrounding the target. The radiation is produced by interactions of intense proton beams with a free liquid mercury jet. We study the influence of different shielding materials and shielding configurations on the energy deposition in the superconducting coils of the target/capture system. We also examine energy depositions for alternative configurations that allow more space for shielding, thus providing more protection for the superconducting coils.

TUP224

Cryogenic Vertical Test Facility for the SRF Cavities at BNL

vacuum, cryogenics, SRF, radiation

1238

R. Than, I. Ben-Zvi, A. Burrill, M.C. Grau, D.L. Lederle, C.J. Liaw, G.T. McIntyre, D. Pate, R. Porqueddu, T.N. Tallerico, J.E. Tuozzolo
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy
A vertical facility has been constructed to test SRF cavities and can be utilized for other use. The liquid helium volume for the large vertical dewar is approximate 84 inches tall by 40 inches diameter with a working clear inner diameter of 38 inch with the inner cold magnetic shield system installed. For radiation enclosure, the test dewar is situated inside a concrete block structure. The structure is above ground and is accessible from the top, and has a retractable concrete roof. A second radiation concrete facility, with ground level access via a labyrinth is also available for testing of smaller cavities in 2 smaller dewars.

WEP107

CSR Shielding Experiment

wakefield, dipole, linac, electron

1677

V. Yakimenko, A.V. Fedotov, M.G. Fedurin, D. Kayran
BNL, Upton, Long Island, New York, USA
V. Litvinenko
Stony Brook University, Stony Brook, USA
P. Muggli
USC, Los Angeles, California, USA

It is well known that the emission of coherent synchrotron radiation (CSR) in a dipole magnets leads to increase in beam energy spread and emittance. At the Brookhaven National Laboratory Accelerator Test Facility (ATF) we study the suppression of CSR emission affect on electron beam in a dipole magnet by two vertically spaced conducting plates. The gap between the plates is controlled by four actuators and could be varied from 0 to 14 mm. Our experimental results show that closing the plates significantly reduces both the beam energy loss and CSR-induced beam energy spread. In this paper we present selected results of the experiment and compare then with rigorous analytical theory.

WEP248

Overview of the LBNE Neutrino Beam

target, proton, simulation, remote-handling

1948

C.D. Moore, Y. He, P. Hurh, J. Hylen, B.G. Lundberg, M.W. McGee, J.R. Misek, N.V. Mokhov, V. Papadimitriou, R.K. Plunkett, R.P. Schultz, G. Velev, K.E. Williams, R.M. Zwaska
Fermilab, Batavia, USA

Funding: Work supported by Fermi Research Alliance, LLC, under contract DE-AC02-07CH11359 with the U.S. Department of Energy.
The Long Baseline Neutrino Experiment (LBNE) will utilize a neutrino beamline facility located at Fermilab. The facility will aim a beam of neutrinos toward a detector placed at the Deep Underground Science and Engineering Laboratory (DUSEL) in South Dakota. The neutrinos are produced in a three step process. First, protons from the Main Injector hit a solid target and produce mesons. Then, the charged mesons are focused by a set of focusing horns into the decay pipe, towards the far detector. Finally, the mesons that enter the decay pipe decay into neutrinos. The parameters of the facility were determined by an amalgam of the physics goals, the Monte Carlo modeling of the facility, and the experience gained by operating the NuMI facility at Fermilab. The initial beam power is expected to be ~700 kW, however some of the parameters were chosen to be able to deal with a beam power of 2.3 MW.

WEP297

A Conceptual Design of the 2+ MW LBNE Beam Absorber

proton, simulation, target, hadron

2041

G. Velev, S.C. Childress, P. Hurh, J. Hylen, A.V. Makarov, N.V. Mokhov, C.D. Moore, I. Novitski
Fermilab, Batavia, USA

Funding: This work is supported by the U.S. Department of Energy.
The Long Baseline Neutrino Experiment (LBNE) will utilize a neutrino beamline facility located at Fermilab. The facility will aim a beam of neutrinos, produced by 60-120 GeV protons from the Fermilab Main Injector, toward a detector placed at the Deep Underground Science and Engineering Laboratory (DUSEL) in South Dakota. Secondary particles that do not decay into muons and neutrinos as well as any residual proton beam must be stopped at the end of the decay region to reduce noise/damage in the downstream muon monitors and reduce activation in the surrounding rock. This goal is achieved by placing an absorber structure at the end of the decay region. The requirements and conceptual design of such an absorber, capable of operating at 2+ MW primary proton beam power, is described.

THP053

The New Approximation of Dose Attenuation Curve in Concrete

neutron, ion, heavy-ion, target

2217

M. Petrichenkov, V.Ya. Chudaev
BINP SB RAS, Novosibirsk, Russia

The analytical approach in shielding calculations is simple and fast method for quick estimations. But it provides less accuracy than Monte-Carlo one. Often the exponential attenuation of dose in shielding is considered. But also it is necessary to take into account the dose increase in the first layers of shielding due to initial accumulation of neutrons. The new approximation of dose attenuation curve in concrete is offered for quick analytical estimations of shielding of hadron accelerators. It allows to make fast estimation of shielding thickness enough correctly.

THP088

Beam Induced Detector Backgrounds at a Muon Collider

collider, background, electron, neutron

2300

S.A. Kahn, M.A.C. Cummings, T.J. Roberts
Muons, Inc, Batavia, USA
D. Hedin, A.O. Morris
Northern Illinois University, DeKalb, Illinois, USA
J.F. Kozminski
Lewis University, Romeoville, Illinois, USA

Funding: Supported in part by SBIR Grant DE-SC0005447
Muon colliders are considered to be an important future energy frontier accelerator. It is possible to build a large muon collider as a circular machine, even at multi-TeV energies, due to the greatly reduced synchrotron radiation expected from muons. In addition to the same physics processes present in an electron collider, a muon collider will have the potential to produce s-channel resonances such as the various Higgs states at an enhanced rate. For a muon collider with 750 GeV/c mu+ and mu- with 10¹² mu per bunch we would expect 4.3x10⁵ muon decays per meter. These muon decays will produce very energetic off momentum electrons that can produce detector backgrounds that can affect the physics. These backgrounds include electrons from muon decays, synchrotron radiation from the decay electrons, hadrons produced by photo-nuclear interactions, coherent and incoherent beam-beam pair production and Bethe-Heitler muon production. In this paper we will discuss these processes and calculate particle fluxes into the detector volume from these background processes.

THP110

Front End Energy Deposition and Collimation Studies for IDS-NF

proton, factory, target, beam-losses

2333

C.T. Rogers
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
D.V. Neuffer
Fermilab, Batavia, USA
P. Snopok
IIT, Chicago, Illinois, USA

Funding: Work supported by DOE, STFC.
The function of the Neutrino Factory front end is to reduce the energy spread and size of the muon beam to a manageable level that will allow reasonable throughput to subsequent system components. Since the Neutrino Factory is a tertiary machine (protons to pions to muons), there is an issue of large background from the pion-producing target. The implications of energy deposition in the front end lattice for the Neutrino Factory are addressed. Several approaches to mitigating the effect are proposed and discussed, including proton absorbers, chicanes, beam collimation, and shielding.

THP225

Characterization and Suppression of the Electromagnetic Interference Induced Phase Shift in the JLab FEL Photo – Injector Advanced Drive Laser System

FEL, laser, controls, electron

2546

F.G. Wilson, D.W. Sexton, S. Zhang
JLAB, Newport News, Virginia, USA

The new drive laser for the photo-cathode gun used in the JLab FEL facility had been experiencing various phase shifts on the order of tens of degrees (>20° at 1497 MHz or >40ps) when changing the Advanced Drive Laser (ADL) micro-pulse frequencies. These phase shifts introduce multiple complications when trying to setup the accelerator for operation, ultimately inhibiting the robustness and overall performance of the FEL. Through rigorous phase measurements and systematic characterizations, we discovered the problems could be attributed to EMI coupling into the ADL phase control loop system, and subsequently resolved the issue of phase shift to within tenths of a degree (<0.5° at 1497 MHz or <1ps). The diagnostic method developed and the knowledge gained through the entire process will prove to be invaluable for future designs of similar systems.