HIAT 2012 - List of Keywords (cavity)

Paper	Title	Other Keywords	Page
MOB01	The FRIB Project – Accelerator Challenges and Progress	linac, cryomodule, ion, controls	8
	J. Wei, E.C. Bernard, N.K. Bultman, F. Casagrande, S. Chouhan, C. Compton, K.D. Davidson, A. Facco, P.E. Gibson, T . Glasmacher, L.L. Harle, K. Holland, M.J. Johnson, S. Jones, D. Leitner, M. Leitner, G. Machicoane, F. Marti, D. Morris, J.A. Nolen, J.P. Ozelis, S. Peng, J. Popielarski, L. Popielarski, E. Pozdeyev, T. Russo, K. Saito, R.C. Webber, J. Weisend, M. Williams, Y. Yamazaki, A. Zeller, Y. Zhang, Q. Zhao FRIB, East Lansing, USA D. Arenius, V. Ganni JLAB, Newport News, Virginia, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661 The Facility for Rare Isotope Beams, a new national user facility funded by the U.S. Department of Energy Office of Science to be constructed and operated by MSU, is currently being designed to provide intense beams of rare isotopes to better understand the physics of nuclei, nuclear astrophysics, fundamental interactions, and applications for society. The FRIB driver linac can accelerate all stable isotopes to energies beyond 200 MeV/u at beam powers up to 400 kW. Key technical R&D programs include low-beta cw SRF cryomodules and highly efficient charge stripping using a liquid lithium film or helium gas. Physical challenges include acceleration of multiple charge states of beams to meet beam-on-target requirements, efficient production and acceleration of intense heavy-ion beams from low to intermediate energies, accommodation of multiple charge stripping scenarios and ion species, designs for both baseline in-flight fragmentation and ISOL upgrade options, and design considerations of machine availability, tunability, reliability, maintainability, and upgradability. We report on the FRIB accelerator design and developments with emphasis on technical challenges and progress.
	Slides MOB01 [4.891 MB]

PO04	The Darmstadt Multi-Frequency Digital Low Level RF System in Pulsed Application	controls, linac, low-level-rf, electron	58
	R. Eichhorn, U. Bonnes, C. Burandt, M. Konrad, P.N. Nonn TU Darmstadt, Darmstadt, Germany G. Schreiber, W. Vinzenz GSI, Darmstadt, Germany
	Funding: Work supported by DFG through CRC 634 and by the BMBF under 06 DA 9024 I Triggered by the need to control the superconducting cavities of the S-DALINAC, the development of a digital low level RF control system was started several years ago. The chosen design proved to be very flexible since other frequencies than the original 3 GHz may be adapted easily: The system converts the RF signal coming from the cavity (e. g. 3 GHz) down to the base band using a hardware I/Q demodulator. The base band signals are digitized by ADCs and fed into a FPGA where the control algorithm is implemented. The resulting signals are I/Q modulated before they are sent back to the cavity. Meanwhile, this system has been successfully operated on 3 GHz, 6 GHz and 325 MHz cavities, on normal and superconducting cavities as well as in cw or pulsed mode. This contribution will focus on the 325 MHz version built to control a pulsed prototype test stand for the p-LINAC at FAIR and possible extensions to even lower frequencies. We will present the architecture of the RF control system as well as results obtained during operation.

PO10	Performance of ALPI New Medium Beta Resonators	vacuum, cathode, pick-up, superconductivity	73
	A.M. Porcellato, F. Chiurlotto, M. De Lazzari, A. Palmieri, V. Palmieri, S. Stark, F. Stivanello INFN/LNL, Legnaro (PD), Italy
	All the Nb sputtered medium beta cavities installed up to the last year in ALPI were produced by upgrading of old previously Pb plated substrates. For the first time this year we had the opportunity to test on line four 160 MHz, β=0.11 QWRs which were designed and built in order to be Nb sputtered. These resonators were sputtered in between 2007 and 2008 and they were tested at low fields (up to 3 MV/m) just after their production when they showed Q-zero values exceeding 1xE9. They were then stored for about three years in plastic bags and installed in ALPI only this year. The on line tests that we performed after installation showed Q-zero values reduced of about a factor five with respect to the ones measured in laboratory. It is the first time we could pick out a Q deterioration caused by storage in air. So far we have not recognized any Q–degradation both when the sputtered cavities were maintained in vacuum for many years and also when they were open to air for a few weeks for cryostat maintenance. In such a case, as it happened in the maintenance of cryostat CR19 housing high beta resonators, we could instead find some improvements in the Q-curves.

PO16	MULTIPHYSICS AND PRESSURE CODE ANALYSIS FOR QUARTER WAVE β=0.085 AND HALF WAVE β=0.29 RESONATORS	niobium, simulation, target, radio-frequency	92
	S.J. Miller, J. Binkowski, A. Facco, M.J. Johnson, Y. Xu FRIB, East Lansing, Michigan, USA
	Funding: U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661 The driver linac design for the Facility for Rare Isotope Beams (FRIB) at Michigan State University (MSU) makes use of four optimized superconducting radio frequency (RF) resonators to accelerate exotic ions to 200 MeV/μ. The RF resonators were optimized using computer simulations for all expected physical encounters and corresponding electrical resonant frequency changes. Principal guidance from the ASME boiler and pressure vessel code (BPVC) were applied.
	Poster PO16 [0.535 MB]

TUA02	A Cost-Effective Energy Upgrade of the ALPI Linac at INFN-Legnaro	linac, ion, simulation, ion-source	106
	G. Bisoffi, M. Comunian, A. Facco, A. Galatà, P. Modanese, R. Pengo, A. Pisent, A.M. Porcellato, S. Stark INFN/LNL, Legnaro (PD), Italy B.B. Chalykh ITEP, Moscow, Russia
	The ALPI SC linac at INFN-LNL is being constantly upgraded in terms of maximum beam energy (Ef) and current, made available for experiments. Presently, a liquid-N cooling scheme is being applied to the RF power couplers of the 16 full Nb resonators, to keep them locked at 5 MV/m, vs. present 3 MV/m. A further upgrade of the 44 “medium beta section” cavities, changing the cavity Cu substrates, was prototyped and is reported at this conference: however it is not fully funded yet and is extremely time-consuming. A cost-effective Ef upgrade is proposed here: to move 2 SC buncher cryostats, which house a single working SC QWR but were designed for 4, at the end of ALPI, equipping them with 4 Nb/Cu QWRs each (new bunchers would either be NC QWRs or a single SC cavity cryostat). The contribution of these cryostats to Ef would be extremely effective: e.g. a Ef~10 MeV/A (Ibeam≥ 1 pnA) Pb beam, a very attractive tool for the Nuclear Physics community, is achievable. A being performed upgrade of ALPI cryoplant, expected to increase the refrigeration capability by ~25%, makes this change possible today. Details of this solutions, as well as its limits, will be presented and discussed
	Slides TUA02 [3.722 MB]

WEC01	Production 72 MHz β=0.077 Superconducting Quarter-wave Cavities for ATLAS	niobium, linac, heavy-ion, acceleration	174
	M.P. Kelly, Z.A. Conway, S.M. Gerbick, M. Kedzie, R.C. Murphy, B. Mustapha, P.N. Ostroumov, T. Reid ANL, Argonne, USA
	A total of eight 72 MHz β=0.077 superconducting quarter-wave cavities have recently been completed at Argonne National Laboratory. Seven of these will installed into the ATLAS superconducting heavy-ion linac as part of a beam intensity upgrade, with one remaining for the purposes of continuing to push the performance limits in these structures. Cavities were fabricated using techniques adapted the worldwide effort push niobium cavities close to the material limits. Key developments include the use of electropolishing on the complete helium-jacketed cavity. Wire EDM has been used instead of traditional niobium machining in order to minimize performance limiting defects near the weld seams. Hydrogen degassing at 600C after electropolishing has also been performed. Initial test results show practical acceleration at 4 Kelvin with cavity voltages, Vacc>3 MV/cavity and at 2 Kelvin with Bpeak>120 mT and Vacc>5 MV/cavity.
	Slides WEC01 [2.843 MB]

WEC03	The SC CW LINAC Demonstrator – 1st Test of an SC CH-cavity with Heavy Ions	linac, solenoid, ion, heavy-ion	182
	S. Mickat, L.A. Dahl GSI, Darmstadt, Germany M. Amberg, K. Aulenbacher, W.A. Barth, V. Gettmann, S. Mickat HIM, Mainz, Germany D. Bänsch, F.D. Dziuba, D. Mäder, H. Podlech, U. Ratzinger, R. Tiede IAP, Frankfurt am Main, Germany
	The superconducting (sc) continuous wave (cw) LINAC Demonstrator is a collaboration project between GSI, the Helmholtz Institute Mainz (HIM), and the Institute for Applied Physics (IAP) at the Goethe University Frankfurt. The aim is a full performance test of a 217 MHz sc Crossbar H-mode (CH) cavity, which provides gradients of 5.1 MV/m at a total length of 0.69 m. In addition the Demonstrator comprises two 9.3 Tesla sc solenoids. The configuration of a CH-cavity embedded by two sc solenoids is taken from a conceptual layout of a new sc cw LINACwith nine CH-cavities and seven solenoids. Such an accelerator is highly desired by a broad community of users requesting heavy ion beam energies in the Coulomb barrier range. A successful test of such an sc multigap structure are an important milestone towards the proposed cw-LINAC.
	Slides WEC03 [1.842 MB]

Paper

Title

Other Keywords

Page

MOB01

The FRIB Project – Accelerator Challenges and Progress

linac, cryomodule, ion, controls

8

J. Wei, E.C. Bernard, N.K. Bultman, F. Casagrande, S. Chouhan, C. Compton, K.D. Davidson, A. Facco, P.E. Gibson, T . Glasmacher, L.L. Harle, K. Holland, M.J. Johnson, S. Jones, D. Leitner, M. Leitner, G. Machicoane, F. Marti, D. Morris, J.A. Nolen, J.P. Ozelis, S. Peng, J. Popielarski, L. Popielarski, E. Pozdeyev, T. Russo, K. Saito, R.C. Webber, J. Weisend, M. Williams, Y. Yamazaki, A. Zeller, Y. Zhang, Q. Zhao
FRIB, East Lansing, USA
D. Arenius, V. Ganni
JLAB, Newport News, Virginia, USA

Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
The Facility for Rare Isotope Beams, a new national user facility funded by the U.S. Department of Energy Office of Science to be constructed and operated by MSU, is currently being designed to provide intense beams of rare isotopes to better understand the physics of nuclei, nuclear astrophysics, fundamental interactions, and applications for society. The FRIB driver linac can accelerate all stable isotopes to energies beyond 200 MeV/u at beam powers up to 400 kW. Key technical R&D programs include low-beta cw SRF cryomodules and highly efficient charge stripping using a liquid lithium film or helium gas. Physical challenges include acceleration of multiple charge states of beams to meet beam-on-target requirements, efficient production and acceleration of intense heavy-ion beams from low to intermediate energies, accommodation of multiple charge stripping scenarios and ion species, designs for both baseline in-flight fragmentation and ISOL upgrade options, and design considerations of machine availability, tunability, reliability, maintainability, and upgradability. We report on the FRIB accelerator design and developments with emphasis on technical challenges and progress.

Slides MOB01 [4.891 MB]

PO04

The Darmstadt Multi-Frequency Digital Low Level RF System in Pulsed Application

controls, linac, low-level-rf, electron

58

R. Eichhorn, U. Bonnes, C. Burandt, M. Konrad, P.N. Nonn
TU Darmstadt, Darmstadt, Germany
G. Schreiber, W. Vinzenz
GSI, Darmstadt, Germany

Funding: Work supported by DFG through CRC 634 and by the BMBF under 06 DA 9024 I
Triggered by the need to control the superconducting cavities of the S-DALINAC, the development of a digital low level RF control system was started several years ago. The chosen design proved to be very flexible since other frequencies than the original 3 GHz may be adapted easily: The system converts the RF signal coming from the cavity (e. g. 3 GHz) down to the base band using a hardware I/Q demodulator. The base band signals are digitized by ADCs and fed into a FPGA where the control algorithm is implemented. The resulting signals are I/Q modulated before they are sent back to the cavity. Meanwhile, this system has been successfully operated on 3 GHz, 6 GHz and 325 MHz cavities, on normal and superconducting cavities as well as in cw or pulsed mode. This contribution will focus on the 325 MHz version built to control a pulsed prototype test stand for the p-LINAC at FAIR and possible extensions to even lower frequencies. We will present the architecture of the RF control system as well as results obtained during operation.

PO10

Performance of ALPI New Medium Beta Resonators

vacuum, cathode, pick-up, superconductivity

73

A.M. Porcellato, F. Chiurlotto, M. De Lazzari, A. Palmieri, V. Palmieri, S. Stark, F. Stivanello
INFN/LNL, Legnaro (PD), Italy

All the Nb sputtered medium beta cavities installed up to the last year in ALPI were produced by upgrading of old previously Pb plated substrates. For the first time this year we had the opportunity to test on line four 160 MHz, β=0.11 QWRs which were designed and built in order to be Nb sputtered. These resonators were sputtered in between 2007 and 2008 and they were tested at low fields (up to 3 MV/m) just after their production when they showed Q-zero values exceeding 1xE9. They were then stored for about three years in plastic bags and installed in ALPI only this year. The on line tests that we performed after installation showed Q-zero values reduced of about a factor five with respect to the ones measured in laboratory. It is the first time we could pick out a Q deterioration caused by storage in air. So far we have not recognized any Q–degradation both when the sputtered cavities were maintained in vacuum for many years and also when they were open to air for a few weeks for cryostat maintenance. In such a case, as it happened in the maintenance of cryostat CR19 housing high beta resonators, we could instead find some improvements in the Q-curves.

PO16

MULTIPHYSICS AND PRESSURE CODE ANALYSIS FOR QUARTER WAVE β=0.085 AND HALF WAVE β=0.29 RESONATORS

niobium, simulation, target, radio-frequency

92

S.J. Miller, J. Binkowski, A. Facco, M.J. Johnson, Y. Xu
FRIB, East Lansing, Michigan, USA

Funding: U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
The driver linac design for the Facility for Rare Isotope Beams (FRIB) at Michigan State University (MSU) makes use of four optimized superconducting radio frequency (RF) resonators to accelerate exotic ions to 200 MeV/μ. The RF resonators were optimized using computer simulations for all expected physical encounters and corresponding electrical resonant frequency changes. Principal guidance from the ASME boiler and pressure vessel code (BPVC) were applied.

Poster PO16 [0.535 MB]

TUA02

A Cost-Effective Energy Upgrade of the ALPI Linac at INFN-Legnaro

linac, ion, simulation, ion-source

106

G. Bisoffi, M. Comunian, A. Facco, A. Galatà, P. Modanese, R. Pengo, A. Pisent, A.M. Porcellato, S. Stark
INFN/LNL, Legnaro (PD), Italy
B.B. Chalykh
ITEP, Moscow, Russia

The ALPI SC linac at INFN-LNL is being constantly upgraded in terms of maximum beam energy (Ef) and current, made available for experiments. Presently, a liquid-N cooling scheme is being applied to the RF power couplers of the 16 full Nb resonators, to keep them locked at 5 MV/m, vs. present 3 MV/m. A further upgrade of the 44 “medium beta section” cavities, changing the cavity Cu substrates, was prototyped and is reported at this conference: however it is not fully funded yet and is extremely time-consuming. A cost-effective Ef upgrade is proposed here: to move 2 SC buncher cryostats, which house a single working SC QWR but were designed for 4, at the end of ALPI, equipping them with 4 Nb/Cu QWRs each (new bunchers would either be NC QWRs or a single SC cavity cryostat). The contribution of these cryostats to Ef would be extremely effective: e.g. a Ef~10 MeV/A (Ibeam≥ 1 pnA) Pb beam, a very attractive tool for the Nuclear Physics community, is achievable. A being performed upgrade of ALPI cryoplant, expected to increase the refrigeration capability by ~25%, makes this change possible today. Details of this solutions, as well as its limits, will be presented and discussed

Slides TUA02 [3.722 MB]

WEC01

Production 72 MHz β=0.077 Superconducting Quarter-wave Cavities for ATLAS

niobium, linac, heavy-ion, acceleration

174

M.P. Kelly, Z.A. Conway, S.M. Gerbick, M. Kedzie, R.C. Murphy, B. Mustapha, P.N. Ostroumov, T. Reid
ANL, Argonne, USA

A total of eight 72 MHz β=0.077 superconducting quarter-wave cavities have recently been completed at Argonne National Laboratory. Seven of these will installed into the ATLAS superconducting heavy-ion linac as part of a beam intensity upgrade, with one remaining for the purposes of continuing to push the performance limits in these structures. Cavities were fabricated using techniques adapted the worldwide effort push niobium cavities close to the material limits. Key developments include the use of electropolishing on the complete helium-jacketed cavity. Wire EDM has been used instead of traditional niobium machining in order to minimize performance limiting defects near the weld seams. Hydrogen degassing at 600C after electropolishing has also been performed. Initial test results show practical acceleration at 4 Kelvin with cavity voltages, Vacc>3 MV/cavity and at 2 Kelvin with Bpeak>120 mT and Vacc>5 MV/cavity.

Slides WEC01 [2.843 MB]

WEC03

The SC CW LINAC Demonstrator – 1st Test of an SC CH-cavity with Heavy Ions

linac, solenoid, ion, heavy-ion

182

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

The superconducting (sc) continuous wave (cw) LINAC Demonstrator is a collaboration project between GSI, the Helmholtz Institute Mainz (HIM), and the Institute for Applied Physics (IAP) at the Goethe University Frankfurt. The aim is a full performance test of a 217 MHz sc Crossbar H-mode (CH) cavity, which provides gradients of 5.1 MV/m at a total length of 0.69 m. In addition the Demonstrator comprises two 9.3 Tesla sc solenoids. The configuration of a CH-cavity embedded by two sc solenoids is taken from a conceptual layout of a new sc cw LINACwith nine CH-cavities and seven solenoids. Such an accelerator is highly desired by a broad community of users requesting heavy ion beam energies in the Coulomb barrier range. A successful test of such an sc multigap structure are an important milestone towards the proposed cw-LINAC.

Slides WEC03 [1.842 MB]