LINAC2014 - List of Keywords (resonance)

Paper	Title	Other Keywords	Page
MOPP028	New Criterion for Shape Optimization of Normal-Conducting Accelerator Cells for High-Gradient Applications	factory, database, simulation, impedance	114
	K.N. Sjobak, A. Grudiev CERN, Geneva, Switzerland E. Adli University of Oslo, Oslo, Norway
	When optimizing the shape of high-gradient accelerating cells, the goal has traditionally been to minimize the peak surface electric field / gradient, or more recently minimizing the peak modified Poynting vector / gradient squared. This paper presents a method for directly comparing these quan- tities, as well as the power flow per circumference / gradient squared. The method works by comparing the maximum tolerable gradient at a fixed pulse length and breakdown rate that can be expected from the different constraints. The paper also presents a set of 120° phase-advance cells for traveling wave structures, which were designed for the new CLIC main linac accelerating structure, and which are optimized according to these criteria.

MOPP053	TTF-III Coupler Modification for CW Operation	simulation, operation, coupling, status	174
	I.V. Gonin, T.N. Khabiboulline, A. Lunin, O.V. Prokofiev, N. Solyak, V.P. Yakovlev Fermilab, Batavia, Illinois, USA
	LCLS-II linac is based on XFEL/ILC superconducting technology, but CW regime of operation requires the modification of components to satisfy LCLS-II requirements. TTF-III coupler is considered as a candidate for a fundamental power coupler for the 1.3 GHz 9-cell accelerating structure at the LCLS-II project. In this paper we discuss the results of multiphysics analysis of the coupler working at various operating regimes. Two major modifications are proposed in order to meet the LCLS-II requirements and eliminate possible overheating: reducing the length of antenna (cold part) and increasing the thickness of a cooper plating on the inner conductor of the warm part of the coupler.

MOPP055	RF Tests of Dressed 325 MHz Single-Spoke Resonators at 2 K	cavity, network, operation, LLRF	180
	A. Hocker, E. Cullerton, B.M. Hanna, W. Schappert, A.I. Sukhanov Fermilab, Batavia, Illinois, USA
	Funding: United States Department of Energy, Contract No.DE- AC02-07CH11359 Fermilab has recently completed an upgrade to its spoke resonator test cryostat to enable testing of cavities in superfluid helium. Two single-spoke resonators with differing helium vessel designs have been tested in this new configuration. Gradient and Q0 performance was studied along with microphonics control and sensitivity of the resonant frequency to pressure variations. A description of the testing and the results obtained are presented.
	Poster MOPP055 [0.437 MB]

MOPP059	Study and Design of the High Power RF Coupler for the CH-Cavity of the Fair pLINAC	coupling, cavity, proton, linac	187
	F. Maimone, G. Clemente, W. Vinzenz GSI, Darmstadt, Germany
	At GSI a proton Linac has been designed and developed in order to provide a 70 MeV proton beam for the FAIR facility. The pLINAC consists of an RFQ followed by six CH-DTL accelerating cavities and the electromagnetic field inside each cavity is generated by seven Klystrons providing up to 2.8 MW power at 325.224 MHz. The high power RF coupling between the Klystron and the accelerating CH-cavity has been studied and an inductive coupling loop has been designed. The coupler insertion inside the cavity and the rotation angle with respect to the magnetic field lines have been adjusted and the results of the analysis of the coupler positioning are presented. A prototype coupler is under construction and the measurement of RF coupling with the CH-cavity is scheduled within this year.

MOPP068	The Fast Piezo-Based Frequency Tuner for SC CH-Cavities	cavity, laser, simulation, operation	214
	M. Amberg, M. Busch, F.D. Dziuba, H. Podlech, U. Ratzinger IAP, Frankfurt am Main, Germany K. Aulenbacher HIM, Mainz, Germany W.A. Barth, V. Gettmann, S. Mickat GSI, Darmstadt, Germany
	Funding: Work supported by HIM, GSI, BMBF Contr. No 05P12RFRBL Superconducting structures are very susceptible to external influences due to their thin walls and their narrow bandwidth. Even small mechanical deformations caused by dynamic effects like microphonic noise, pressure fluctuations of the liquid helium bath or Lorentz-Force-Detuning can lead to resonance frequency changes of the cavity which are much larger than the bandwidth. To compensate the slow and fast resonance frequency variations during operation a compact frequency tuner prototype equipped with a stepper motor and a piezo actuator has been developed at the Institute for Applied Physics (IAP) of Frankfurt University. In this paper, the tuner design and the results of first room temperature measurements of the tuner prototype are presented.
	Poster MOPP068 [2.304 MB]

TUPP064	Zero-Current Longitudinal Beam Dynamics	lattice, damping, cavity, linac	572
	J.-M. Lagniel GANIL, Caen, France
	In linacs, the longitudinal focalization is done by nonlinear forces and the acceleration induces a damping of the phase oscillations. The longitudinal beam dynamics is therefore complex, even when the nonlinear space-charge forces are ignored. The three different ways to study and understand this zero-current longitudinal beam dynamics will be presented and compared.

TUPP089	Tuning and Field Stabilization of the CERN Linac4 Drift Tube Linac	DTL, linac, cavity, simulation	631
	M.R. Khalvati IPM, Tehran, Iran S. Ramberger CERN, Geneva, Switzerland
	The Drift Tube Linac (DTL) for the new linear accelerator Linac4 at CERN will accelerate H–beams of up to 40 mA average pulse current from 3 to 50 MeV. The structure consists of three cavities. The first cavity (Tank1) is a 3.9 m long tank containing 38 drift tubes, 10 fixed tuners, 2 movable tuners and 12 post-couplers, operating at a frequency of 352.2 MHz and an average accelerating field of 3.1 MV/m. This paper reports on the results and procedures used for the low–power tuning, stabilization and power coupler tuning carried out on the first Linac4 DTL tank. The upgrade of the bead pull measurement system and twists to the well-known tilt sensitivity technique are discussed.

THPP003	Cooling of High Pressure Insulating Gas for 3 MeV DC Accelerator: an Alternate Approach	electron, controls, high-voltage, interlocks	839
	S.R. Ghodke, S. Acharya, R. Barnwal, K.P. Dixit, L.M. Gantayet, B.S. Israel, D. Jayaprakash, K. Mahender, K.C. Mittal, S. Nayak, R.N. Rajan, D.K. Sharma, V. Sharma, S.K. Suneet, D.P. Suryaprakash BARC, Mumbai, India
	3 MeV Accelerator Project working inside the ‘Electron Beam Centre’ (EBC) building at Kharghar, Navi Mumbai. Generally in DC and Pelletron accelerators Nitrogen/SF6 gas is taken out from accelerator tank and it is cooled by separate heat exchanger and blower unit outside the accelerator tank. In our alternate approach we have designed fan/ blower to work under high pressure inside accelerator tank. Fans are designed to work in high pressure SF6 environment at 7 bar absolute pressure with 42 kg/m3 SF6 gas density. Fan throughs air over radiator type finned tube heat exchanger, installed inside accelerator tank. Fan speeds are controlled through variable frequency drive. Two numbers of such assemblies are fabricated, installed and tested in Nitrogen and SF6 gas environment at different pressure and variable fan speed. Performances are recorded and plotted in graphical form. These cooling systems are shown excellent performance in last five years. Paper will discuss about design of cooling system, cooling calculation of fan, fabrication of fan and heat exchanger, 5 TR chiller unit, variable frequency drive, fan performance etc.
	Poster THPP003 [1.644 MB]

THPP019	Low Kick Coupler for Superconducting Cavities	cavity, emittance, dipole, linac	876
	R.G. Eichhorn, C. Egerer, V. Veshcherevich Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Results from the high current, low emittance photo injector at Cornell revealed that even with two opposing input couplers, the beam emittance is affected by the coupler kick. As a result, a coupler with low transverse kick is proposed for use in superconducting accelerating cavities. In this coupler, a rectangular waveguide transforms into a coaxial line inside the beam pipe. The geometry of the coupler is tuned to minimize the transverse kick that is important for linear accelerators with low emittance. The coupler can be used in ERL injectors or other linacs for high brightness light sources.

THPP048	Design of a Compact Lever Slow/Fast Tuner for 650 MHz Cavities for Project X	cavity, operation, simulation, SRF	957
	I.V. Gonin, E. Borissov, T.N. Khabiboulline, Y.M. Pischalnikov, V.P. Yakovlev Fermilab, Batavia, Illinois, USA
	Fermilab is developing 5-cell elliptical 650 MHz β=0.6 and β=0.9 cavities for Project X. A compact fast/slow lever tuner intended for both types of cavities has been developed for final tuning of the resonance frequency of the cavity after cooling down and to compensate the resonance frequency variations of the cavity during operation coming from liquid helium pressure fluctuations. The updated helium vessel (presented at this conference) is equipped with the tuner located at one of the end of the cavity. The tuner design and results of ANSYS analysis of their properties are presented.

THPP057	Results of Cold Tests of the Fermilab SSR1 Cavities	cavity, cryomodule, radiation, SRF	979
	A.I. Sukhanov, M.H. Awida, P. Berrutti, E. Cullerton, B.M. Hanna, A. Hocker, T.N. Khabiboulline, O.S. Melnychuk, D. Passarelli, R.V. Pilipenko, Y.M. Pischalnikov, L. Ristori, A.M. Rowe, W. Schappert, D.A. Sergatskov Fermilab, Batavia, Illinois, USA
	Fermilab is currently building the Project X Injector experiment (PXIE). The PXIE linac will accelerate a 1 mA H⁻ beam up to 30 MeV and serve as a testbed for validation of Project X concepts and mitigation of technical risks. A cryomodule of eight superconducting RF Single Spoke Resonators of type 1 (SSR1) cavities operating at 325 MHz is an integral part of PXIE. Ten SSR1 cavities were manufactured in industry and delivered to Fermilab. We discuss tests of nine bare SSR1 cavities at the Fermilab Vertical Test Stand (VTS). Recently, one of the SSR1 cavities was welded inside a helium jacket. Results of the test of this cavity in the Fermilab Spoke Test Cryostat (STC) are shown. We report on the measured performance parameters of SSR1 cavities achieved during the tests.

THPP062	BERLinPro SRF Gun Notch Filter Investigations	gun, cathode, cavity, SRF	995
	E.N. Zaplatin FZJ, Jülich, Germany J. Knobloch, A. Neumann HZB, Berlin, Germany
	BERLinPro is an approved ERL project to demonstrate energy recovery at 100 mA beam current by pertaining a high quality beam. These goals place stringent requirements on the SRF cavity (1300 MHz, β=1) for the photoinjector which has to deliver a small emittance 100 mA beam with at least 1.8 MeV kinetic energy while limited by fundamental power coupler performance to about 230 kW forward power. The RF and beam dynamics gun cavity features 1.4 λ/2 cell resonator. To protect a cathode housing from RF power propagation from the cavity cells and to reduce its component heating a high-frequency notch filter was investigated. We present results of different schemes of choke cell combinations to optimize filter parameters. The goal for the filter design was the RF power attenuation better than -30 dB in the wide frequency range.

THPP078	Troubleshooting and Performances of Type-B Spiral2 Series Cryomodule	cavity, cryomodule, coupling, pick-up	1037
	D. Longuevergne, F. Chatelet, C. Commeaux, N. Gandolfo, D. Grolet, C. Joly, J. Lesrel, R. Martret, G. Michel, G. Olry, L. Renard, A. Stephen, P. Szott IPN, Orsay, France
	SPIRAL2 aims at building a multi-purpose facility dedicated to nuclear physics studies, including the production of rich-neutrons isotopes. The multi-beam linear accelerator is composed of superconducting accelerating modules operating at 4.2K and warm focusing magnets. IPN Orsay is in charge of the high energy (Type-B) accelerating modules, each hosting two superconducting 88 MHz quarter-wave resonators made of bulk Niobium operating at an accelerating gradient of 6.5 MV/m (β=0.12). The first Type-B series cryomodule has been validated in April 2013. Since then, four additional cryomodules have been validated in a row showing a very high-quality and reliable assembly procedure. Some of encountered problems (tuner hysteresis, magnetic shielding,) and associated solutions will be presented. Moreover, a comparison of cavity performances between vertical cryostat and cryomodule tests will be done.

THPP092	Development of Slow Neutron Accelerator for Rebunching Pulsed Neutrons	neutron, experiment, acceleration, impedance	1062
	S. Imajo Kyoto University, Kyoto, Japan Y. Fuwa, Y. Iwashita, R. Kitahara Kyoto ICR, Uji, Kyoto, Japan T. Ino KEK, Ibaraki, Japan M. Kitaguchi, H.M. Shimizu Nagoya University, Nagoya, Japan K. Mishima ICEPP, Tokyo, Japan
	Low energy neutrons can be accelerated or decelerated by the technique of AFP-NMR with RF and gradient magnetic fields. The neutrons have magnetic moments, hence their potential energy are not cancelled before and after passage of magnetic fields and their kinetic energy change finally when their spins are flipped in the fields. Nowadays most measurements of the neutron electric dipole moment (nEDM) are carried out with ultra cold neutrons (UCN), whose kinetic energies are lower than about 300 neV, and with a small storage bottle to reduce the systematic errors. In such experiments highly dense UCNs are desired. The spallation neutron sources generate high-density neutrons, however, the pulsed neutrons with several velocities are diffused in guide tubes under long beam intervals. It is necessary to focus and rebunch UCN temporally upon the bottle by controlling their velocities in nEDM experiments at those facilities. We demonstrated such rebuncher and have been developed the advanced apparatus which makes it possible to handle broader energy range UCN. The design, measured characteristics, the experimental setup and the obtained results at J-PARC will be described.

Paper

Title

Other Keywords

Page

MOPP028

New Criterion for Shape Optimization of Normal-Conducting Accelerator Cells for High-Gradient Applications

factory, database, simulation, impedance

114

K.N. Sjobak, A. Grudiev
CERN, Geneva, Switzerland
E. Adli
University of Oslo, Oslo, Norway

When optimizing the shape of high-gradient accelerating cells, the goal has traditionally been to minimize the peak surface electric field / gradient, or more recently minimizing the peak modified Poynting vector / gradient squared. This paper presents a method for directly comparing these quan- tities, as well as the power flow per circumference / gradient squared. The method works by comparing the maximum tolerable gradient at a fixed pulse length and breakdown rate that can be expected from the different constraints. The paper also presents a set of 120° phase-advance cells for traveling wave structures, which were designed for the new CLIC main linac accelerating structure, and which are optimized according to these criteria.

MOPP053

TTF-III Coupler Modification for CW Operation

simulation, operation, coupling, status

174

I.V. Gonin, T.N. Khabiboulline, A. Lunin, O.V. Prokofiev, N. Solyak, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA

LCLS-II linac is based on XFEL/ILC superconducting technology, but CW regime of operation requires the modification of components to satisfy LCLS-II requirements. TTF-III coupler is considered as a candidate for a fundamental power coupler for the 1.3 GHz 9-cell accelerating structure at the LCLS-II project. In this paper we discuss the results of multiphysics analysis of the coupler working at various operating regimes. Two major modifications are proposed in order to meet the LCLS-II requirements and eliminate possible overheating: reducing the length of antenna (cold part) and increasing the thickness of a cooper plating on the inner conductor of the warm part of the coupler.

MOPP055

RF Tests of Dressed 325 MHz Single-Spoke Resonators at 2 K

cavity, network, operation, LLRF

180

A. Hocker, E. Cullerton, B.M. Hanna, W. Schappert, A.I. Sukhanov
Fermilab, Batavia, Illinois, USA

Funding: United States Department of Energy, Contract No.DE- AC02-07CH11359
Fermilab has recently completed an upgrade to its spoke resonator test cryostat to enable testing of cavities in superfluid helium. Two single-spoke resonators with differing helium vessel designs have been tested in this new configuration. Gradient and Q0 performance was studied along with microphonics control and sensitivity of the resonant frequency to pressure variations. A description of the testing and the results obtained are presented.

Poster MOPP055 [0.437 MB]

MOPP059

Study and Design of the High Power RF Coupler for the CH-Cavity of the Fair pLINAC

coupling, cavity, proton, linac

187

F. Maimone, G. Clemente, W. Vinzenz
GSI, Darmstadt, Germany

At GSI a proton Linac has been designed and developed in order to provide a 70 MeV proton beam for the FAIR facility. The pLINAC consists of an RFQ followed by six CH-DTL accelerating cavities and the electromagnetic field inside each cavity is generated by seven Klystrons providing up to 2.8 MW power at 325.224 MHz. The high power RF coupling between the Klystron and the accelerating CH-cavity has been studied and an inductive coupling loop has been designed. The coupler insertion inside the cavity and the rotation angle with respect to the magnetic field lines have been adjusted and the results of the analysis of the coupler positioning are presented. A prototype coupler is under construction and the measurement of RF coupling with the CH-cavity is scheduled within this year.

MOPP068

The Fast Piezo-Based Frequency Tuner for SC CH-Cavities

cavity, laser, simulation, operation

214

M. Amberg, M. Busch, F.D. Dziuba, H. Podlech, U. Ratzinger
IAP, Frankfurt am Main, Germany
K. Aulenbacher
HIM, Mainz, Germany
W.A. Barth, V. Gettmann, S. Mickat
GSI, Darmstadt, Germany

Funding: Work supported by HIM, GSI, BMBF Contr. No 05P12RFRBL
Superconducting structures are very susceptible to external influences due to their thin walls and their narrow bandwidth. Even small mechanical deformations caused by dynamic effects like microphonic noise, pressure fluctuations of the liquid helium bath or Lorentz-Force-Detuning can lead to resonance frequency changes of the cavity which are much larger than the bandwidth. To compensate the slow and fast resonance frequency variations during operation a compact frequency tuner prototype equipped with a stepper motor and a piezo actuator has been developed at the Institute for Applied Physics (IAP) of Frankfurt University. In this paper, the tuner design and the results of first room temperature measurements of the tuner prototype are presented.

Poster MOPP068 [2.304 MB]

TUPP064

Zero-Current Longitudinal Beam Dynamics

lattice, damping, cavity, linac

572

J.-M. Lagniel
GANIL, Caen, France

In linacs, the longitudinal focalization is done by nonlinear forces and the acceleration induces a damping of the phase oscillations. The longitudinal beam dynamics is therefore complex, even when the nonlinear space-charge forces are ignored. The three different ways to study and understand this zero-current longitudinal beam dynamics will be presented and compared.

TUPP089

Tuning and Field Stabilization of the CERN Linac4 Drift Tube Linac

DTL, linac, cavity, simulation

631

M.R. Khalvati
IPM, Tehran, Iran
S. Ramberger
CERN, Geneva, Switzerland

The Drift Tube Linac (DTL) for the new linear accelerator Linac4 at CERN will accelerate H–beams of up to 40 mA average pulse current from 3 to 50 MeV. The structure consists of three cavities. The first cavity (Tank1) is a 3.9 m long tank containing 38 drift tubes, 10 fixed tuners, 2 movable tuners and 12 post-couplers, operating at a frequency of 352.2 MHz and an average accelerating field of 3.1 MV/m. This paper reports on the results and procedures used for the low–power tuning, stabilization and power coupler tuning carried out on the first Linac4 DTL tank. The upgrade of the bead pull measurement system and twists to the well-known tilt sensitivity technique are discussed.

THPP003

Cooling of High Pressure Insulating Gas for 3 MeV DC Accelerator: an Alternate Approach

electron, controls, high-voltage, interlocks

839

S.R. Ghodke, S. Acharya, R. Barnwal, K.P. Dixit, L.M. Gantayet, B.S. Israel, D. Jayaprakash, K. Mahender, K.C. Mittal, S. Nayak, R.N. Rajan, D.K. Sharma, V. Sharma, S.K. Suneet, D.P. Suryaprakash
BARC, Mumbai, India

3 MeV Accelerator Project working inside the ‘Electron Beam Centre’ (EBC) building at Kharghar, Navi Mumbai. Generally in DC and Pelletron accelerators Nitrogen/SF6 gas is taken out from accelerator tank and it is cooled by separate heat exchanger and blower unit outside the accelerator tank. In our alternate approach we have designed fan/ blower to work under high pressure inside accelerator tank. Fans are designed to work in high pressure SF6 environment at 7 bar absolute pressure with 42 kg/m3 SF6 gas density. Fan throughs air over radiator type finned tube heat exchanger, installed inside accelerator tank. Fan speeds are controlled through variable frequency drive. Two numbers of such assemblies are fabricated, installed and tested in Nitrogen and SF6 gas environment at different pressure and variable fan speed. Performances are recorded and plotted in graphical form. These cooling systems are shown excellent performance in last five years. Paper will discuss about design of cooling system, cooling calculation of fan, fabrication of fan and heat exchanger, 5 TR chiller unit, variable frequency drive, fan performance etc.

Poster THPP003 [1.644 MB]

THPP019

Low Kick Coupler for Superconducting Cavities

cavity, emittance, dipole, linac

876

R.G. Eichhorn, C. Egerer, V. Veshcherevich
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Results from the high current, low emittance photo injector at Cornell revealed that even with two opposing input couplers, the beam emittance is affected by the coupler kick. As a result, a coupler with low transverse kick is proposed for use in superconducting accelerating cavities. In this coupler, a rectangular waveguide transforms into a coaxial line inside the beam pipe. The geometry of the coupler is tuned to minimize the transverse kick that is important for linear accelerators with low emittance. The coupler can be used in ERL injectors or other linacs for high brightness light sources.

THPP048

Design of a Compact Lever Slow/Fast Tuner for 650 MHz Cavities for Project X

cavity, operation, simulation, SRF

957

I.V. Gonin, E. Borissov, T.N. Khabiboulline, Y.M. Pischalnikov, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA

Fermilab is developing 5-cell elliptical 650 MHz β=0.6 and β=0.9 cavities for Project X. A compact fast/slow lever tuner intended for both types of cavities has been developed for final tuning of the resonance frequency of the cavity after cooling down and to compensate the resonance frequency variations of the cavity during operation coming from liquid helium pressure fluctuations. The updated helium vessel (presented at this conference) is equipped with the tuner located at one of the end of the cavity. The tuner design and results of ANSYS analysis of their properties are presented.

THPP057

Results of Cold Tests of the Fermilab SSR1 Cavities

cavity, cryomodule, radiation, SRF

979

A.I. Sukhanov, M.H. Awida, P. Berrutti, E. Cullerton, B.M. Hanna, A. Hocker, T.N. Khabiboulline, O.S. Melnychuk, D. Passarelli, R.V. Pilipenko, Y.M. Pischalnikov, L. Ristori, A.M. Rowe, W. Schappert, D.A. Sergatskov
Fermilab, Batavia, Illinois, USA

Fermilab is currently building the Project X Injector experiment (PXIE). The PXIE linac will accelerate a 1 mA H⁻ beam up to 30 MeV and serve as a testbed for validation of Project X concepts and mitigation of technical risks. A cryomodule of eight superconducting RF Single Spoke Resonators of type 1 (SSR1) cavities operating at 325 MHz is an integral part of PXIE. Ten SSR1 cavities were manufactured in industry and delivered to Fermilab. We discuss tests of nine bare SSR1 cavities at the Fermilab Vertical Test Stand (VTS). Recently, one of the SSR1 cavities was welded inside a helium jacket. Results of the test of this cavity in the Fermilab Spoke Test Cryostat (STC) are shown. We report on the measured performance parameters of SSR1 cavities achieved during the tests.

THPP062

BERLinPro SRF Gun Notch Filter Investigations

gun, cathode, cavity, SRF

995

E.N. Zaplatin
FZJ, Jülich, Germany
J. Knobloch, A. Neumann
HZB, Berlin, Germany

BERLinPro is an approved ERL project to demonstrate energy recovery at 100 mA beam current by pertaining a high quality beam. These goals place stringent requirements on the SRF cavity (1300 MHz, β=1) for the photoinjector which has to deliver a small emittance 100 mA beam with at least 1.8 MeV kinetic energy while limited by fundamental power coupler performance to about 230 kW forward power. The RF and beam dynamics gun cavity features 1.4 λ/2 cell resonator. To protect a cathode housing from RF power propagation from the cavity cells and to reduce its component heating a high-frequency notch filter was investigated. We present results of different schemes of choke cell combinations to optimize filter parameters. The goal for the filter design was the RF power attenuation better than -30 dB in the wide frequency range.

THPP078

Troubleshooting and Performances of Type-B Spiral2 Series Cryomodule

cavity, cryomodule, coupling, pick-up

1037

D. Longuevergne, F. Chatelet, C. Commeaux, N. Gandolfo, D. Grolet, C. Joly, J. Lesrel, R. Martret, G. Michel, G. Olry, L. Renard, A. Stephen, P. Szott
IPN, Orsay, France

SPIRAL2 aims at building a multi-purpose facility dedicated to nuclear physics studies, including the production of rich-neutrons isotopes. The multi-beam linear accelerator is composed of superconducting accelerating modules operating at 4.2K and warm focusing magnets. IPN Orsay is in charge of the high energy (Type-B) accelerating modules, each hosting two superconducting 88 MHz quarter-wave resonators made of bulk Niobium operating at an accelerating gradient of 6.5 MV/m (β=0.12). The first Type-B series cryomodule has been validated in April 2013. Since then, four additional cryomodules have been validated in a row showing a very high-quality and reliable assembly procedure. Some of encountered problems (tuner hysteresis, magnetic shielding,) and associated solutions will be presented. Moreover, a comparison of cavity performances between vertical cryostat and cryomodule tests will be done.

THPP092

Development of Slow Neutron Accelerator for Rebunching Pulsed Neutrons

neutron, experiment, acceleration, impedance

1062

S. Imajo
Kyoto University, Kyoto, Japan
Y. Fuwa, Y. Iwashita, R. Kitahara
Kyoto ICR, Uji, Kyoto, Japan
T. Ino
KEK, Ibaraki, Japan
M. Kitaguchi, H.M. Shimizu
Nagoya University, Nagoya, Japan
K. Mishima
ICEPP, Tokyo, Japan

Low energy neutrons can be accelerated or decelerated by the technique of AFP-NMR with RF and gradient magnetic fields. The neutrons have magnetic moments, hence their potential energy are not cancelled before and after passage of magnetic fields and their kinetic energy change finally when their spins are flipped in the fields. Nowadays most measurements of the neutron electric dipole moment (nEDM) are carried out with ultra cold neutrons (UCN), whose kinetic energies are lower than about 300 neV, and with a small storage bottle to reduce the systematic errors. In such experiments highly dense UCNs are desired. The spallation neutron sources generate high-density neutrons, however, the pulsed neutrons with several velocities are diffused in guide tubes under long beam intervals. It is necessary to focus and rebunch UCN temporally upon the bottle by controlling their velocities in nEDM experiments at those facilities. We demonstrated such rebuncher and have been developed the advanced apparatus which makes it possible to handle broader energy range UCN. The design, measured characteristics, the experimental setup and the obtained results at J-PARC will be described.