IPAC2013 - List of Keywords (stripper)

Paper	Title	Other Keywords	Page
MOPFI025	Progress Towards High-Intensity Heavy-Ion Beams at RIKEN RIBF	ion, cyclotron, ECRIS, DTL	333
	O. Kamigaito, T. Dantsuka, M. Fujimaki, T. Fujinawa, N. Fukunishi, H. Hasebe, Y. Higurashi, E. Ikezawa, H. Imao, T. Kageyama, M. Kase, M. Kidera, M. Komiyama, H. Kuboki, K. Kumagai, T. Maie, M. Nagase, T. Nakagawa, M. Nakamura, J. Ohnishi, H. Okuno, K. Ozeki, N. Sakamoto, K. Suda, H. Watanabe, T. Watanabe, Y. Watanabe, K. Yamada, H. Yamasawa RIKEN Nishina Center, Wako, Japan
	The RIKEN RIBF(Radioactive Isotope Beam Factory) accelerator complex has been designed and constructed to provide heavy-ion beams from D to U ions with the energy of 400 MeV/u to the maximum. Though the goal intensity is 1 particle μ amperes for the whole mass range, the intensities of very heavy-ions from Ca to U are still not satisfactory. In 2012, owing to the intensity upgrade of ⁴⁸Ca beams from ECR ion source, the beam current of ⁴⁸Ca was 400 pnA which was improved by factors of 2 in comparison with that in 2011. Since 2011, the new injector RILAC2 has been successfully commissioned and operated very stably for beam service time, increasing the U beam intensity by an order of magnitude. Because it was no longer realistic to use carbon foil to strip the charge of intense U beams, in 2012 the Low-Z gas stripper system instead of the standard carbon foil system has been introduced and successfully worked. To accelerate the ²³⁸U⁶⁴⁺ beams provided by the Low-Z gas stripper, modification of the following Fixed-frequency Ring Cyclotron was performed. In 2012, 15 pnA uranium beams which was four times larger than that provided in 2011 has been achieved.

MOPFI063	Progress on Designs for 180 MeV Injection into the ISIS Synchrotron	injection, dipole, septum, synchrotron	428
	B. Jones, D.J. Adams, B.S. Drumm, M.C. Hughes, A.J. McFarland, C.M. Warsop STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	The ISIS Facility at the Rutherford Appleton Laboratory in the UK produces intense neutron and muon beams for condensed matter research. It operates at 50Hz accelerating beam via a 70 MeV H⁻ linac and an 800 MeV proton synchrotron, delivering a mean beam power of 0.2 MW. As an initial step towards megawatt operations at ISIS, a study of replacement of the existing injector with a new 180 MeV H⁻ linac has recently been completed. This could enable an increase in beam power to approximately 0.5 MW. The ISIS Facility at the Rutherford Appleton Laboratory in the UK produces intense neutron and muon beams for condensed matter research. It accelerates 3×10¹³ protons per pulse (ppp) at 50 Hz through a 70 MeV H− linac and an 800 MeV proton synchrotron, delivering a mean beam power of ~0.2 MW. A favoured first step to upgrade ISIS towards the megawatt regime is replacement of the linac with a new 180 MeV injector described in [1]. Studies of this upgrade, which aims to increase mean beam power up to 0.5 MW are outlined in [2]. This paper reports on recent development of the designs including the injection septum, dipole power supplies and detailed tracking of partially stripped foil products.

MOPME022	Beam Commissioning of Two Horizontal Pulse Steering Magnets for Changing Injection Painting Area from MLF to MR in the 3-GeV RCS of J-PARC	injection, beam-transport, emittance, target	518
	P.K. Saha, H. Harada, N. Hayashi, H. Hotchi, M. Kinsho, T. Takayanagi, N. Tani JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan Y. Irie KEK, Ibaraki, Japan S. Kato Tohoku University, Graduate School of Science, Sendai, Japan
	We have been successfully commissioned two pulse steering magnets installed in the Linac to 3-GeV RCS (Rapid Cycling Synchrotron) injection beam transport (BT) line of J-PARC. RCS has to deliver a simultaneous as well as specific beam as demand by the downstream facilities of MLF (Material and Life Science Facility) and the MR (Main Ring). In order to obtain relatively a smaller transverse emittance at extraction, those magnets were designed to perform a smaller injection painting for the MR beam as compared to the MLF one. As stripper foil position is fixed for the charge exchange H⁻ injection, inclination of the injected beam centroid on foil for the MR beam is only moved to a smaller value by the pulse steering magnets, while DC septum magnets are fixed as determined first for the MLF beam. Their parameters were found to be very consistent with expectation and thus already in operation for switching to a painting area of 100 pi mm mrad for the MR beam as compared to that of 150 pi mm mrad for the MLF beam.

TUPWO009	Decoupling Capabilities Study of the Emittance Transfer Section	emittance, solenoid, quadrupole, coupling	1895
	C. Xiao, O.K. Kester IAP, Frankfurt am Main, Germany L. Groening, O.K. Kester, M.T. Maier GSI, Darmstadt, Germany
	Flat beams are those which feature unequal emittances in the horizontal and vertical phase space. The present paper is on the planning of the experimental proof of principle. Detailed simulations of the experiment, initially based on linear matrix transformations, are performed. The remarkable flexibility of the set-up w.r.t. to decoupling is addressed, as it can provide an one-knob tool to set the horizontal and vertical emittance partitioning. It was found that the decoupling capability of the set-up is remarkably flexible and the impact and discussion of this finding is treated in a dedicated section

WEPEA034	Study on the Beam Dynamics in the RISP Driver Linac	linac, quadrupole, ion, resonance	2576
	H.J. Kim, H.J. Jang, D. Jeon IBS, Daejeon, Republic of Korea J.G. Hwang Kyungpook National University, Daegu, Republic of Korea E.-S. Kim KNU, Deagu, Republic of Korea
	Abstract Rare Isotope Science Project (RISP) has been proposed as a multi-purpose accelerator facility for providing beams of exotic rare isotopes of various energies. The RISP driver linac which is used to accelerate the beam, for an example, Uranium ions from 0.3 MeV/u to 200 MeV/u consists of superconducting RF cavities and warm quadrupole magnets for focusing heavy ion beams. Requirement of the linac design is especially high for acceleration of multiple charge beams. In this paper, we present the requirements of dynamic errors and correction schemes to minimize the beam centroid oscillation and preserve beam losses under control.

THPPA01	Realization of New Charge-state Stripper for High-power Uranium Ion Beams	ion, target, acceleration, electron	3135
	H. Imao RIKEN Nishina Center, Wako, Japan
	Recent works to realize the new charge-state stripper using recirculating helium gas are presented. Very limited lifetimes of conventional solid-state strippers due to huge dE/dx for very heavy ion beams (e.g., for uranium ions, several thousand times larger than protons at the energy around 10 MeV/u) were a principal bottleneck for their multi-stage acceleration at high intensities. The new stripping system is characterized by its infinite lifetime, efficient stripping and small beam degradation even for the world’s most intense uranium ion beams provided by the RIBF (more than 1 pμA at the injected energy of 11 MeV/u). Successful operations of the system in 2012 greatly contribute to the remarkable expansion of the accelerator performance of the RIBF that will allow an enormous breakthrough for exploring new domains of the nuclear world in the next several years; the peak intensity of the uranium beam has reached 15.1 pnA (almost 10¹¹ pps) at 345 MeV/u and the average intensity provided for the users has become ten times higher than it was in 2011.
	Slides THPPA01 [6.535 MB]

THPFI011	Thermal Simulations of Charge-exchange Stripper Foils for High-melting-point Materials	simulation, injection, radiation, proton	3312
	Y. Takeda KEK, Ibaraki, Japan M.A. Plum ORNL, Oak Ridge, Tennessee, USA
	Charge-exchange stripper foils can be very quickly broken by high-current beams. Hence, a long-lived foil that can withstand prolonged beam irradiation is eagerly awaited. It is well known that the maximum temperature of the foil plays an important role in the foil lifetime. Therefore, the temperature distribution map and the maximum temperature of the foils were investigated in detail by using simulation software of the finite element method and applications with ANSYS. Moreover, the heating properties of several kinds of high-melting-point materials were researched. According to the results, stripper foils of the same effective thickness showed drastically different maximum temperatures, differing by up to about 200 K. From these results, we show that the emissivity and specific heat of the foil considerably influences its maximum temperature.

THPWO010	Charge Stripping Tests of High Current Uranium Ion Beams with Methane and Hydrogen Gas Strippers and Carbon Foils at the GSI UNILAC	ion, heavy-ion, vacuum, target	3779
	B. Schlitt, W.A. Barth, G. Clemente, L. Groening, M. Kaiser, B. Lommel, M.T. Maier, S. Mickat, J. Steiner, H. Vormann GSI, Darmstadt, Germany
	At the GSI UNILAC, a nitrogen gas stripper is routinely used for stripping of heavy ion beams at 1.4 MeV/u. Different approaches to optimize the stripping efficiency as well as different options to increase the ion charge states for delivery to SIS18 are being investigated. The existing gas stripper was operated with methane and hydrogen gas for stripping of high current uranium ion beams. The results as well as the limitations of these tests will be presented and will be compared to standard nitrogen operation of the gas stripper. In addition, newest results using differently prepared carbon stripping foils for the same ion beams will be reported.

THPWO038	Electron Stripping of High-intensity ²³⁸U Ion Beam with Recirculating He Gas	ion, electron, target, acceleration	3851
	H. Imao RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama, Japan T. Dantsuka, M. Fujimaki, N. Fukunishi, H. Hasebe, O. Kamigaito, M. Kase, H. Kuboki, K. Kumagai, T. Maie, H. Okuno, T. Watanabe, Y. Watanabe, K. Yamada, Y. Yano RIKEN Nishina Center, Wako, Japan
	Next-generation in-flight RI beam facilities such as RIBF and FRIB pursue powerful and energetic ²³⁸U ion beams to produce thousands of new isotopes. For their efficient acceleration, a durable electron stripper in the intermediate energy region around 10-20 MeV/u is indispensable. However, there is no available stripper for the U beams with the intensity of more than 1 puA so far because of the lifetime problem of thin solid strippers caused by high energy loss. 　In the present study, a novel electron stripping system employing high-flow rate He gas circulation (200 L/min) has been developed. He gas with the thickness of 0.6 mg/cm² is confined and separated from beamline vacuum using five-stage differentially-pumped sections. To avoid huge gas consumption, a clean gas recycling is achieved with multi-stage mechanical booster pump array. The recycling rate of He gas was achieved as more than 99%. The system was successfully operated in user runs with U³⁵⁺ beams more than 1 puA injected at 10.8 MeV/u for the first time. U⁶⁴⁺ beams were stably delivered to subsequent accelerators with the stripping efficiency of 23% without any deterioration of the system.

THPWO065	Optics Design and Correction of High Order Aberration of the Charge Stripper Beam Line of RAON	sextupole, ion, emittance, optics	3906
	H.J. Kim, D. Jeon, H.J. Kim IBS, Daejeon, Republic of Korea J.G. Hwang, E.-S. Kim Kyungpook National University, Daegu, Republic of Korea
	RAON (Rare isotope Accelerator Of Newness) in Korea will be providing the 400 kW of 238U⁷⁹⁺ beam with 8 puA and 200 MeV/u. One of the critical components of this project in the SCL is the design of the charge stripper. Between the two segments of the SCL, the charge stripper strips electrons from ion beams to enhance the acceleration efficiency in the following SCL2. For high efficiency of the acceleration and high power in SCL2, the optimum energy of striped ion in solid carbon foil stripper for SCL1 was estimated by using code LISE. The thickness of the solid carbon foil is 300 ug/m2. Based on this study, the charge stripping efficiency of solid carbon stripper is ~80 %. For the charge selection from ions which produced by the solid carbon stripper, the dispersive section is required in down-stream of the foil. The designed optics for dispersive section is based on the mirror-symmetric optics to minimize the effect of high-order aberration. And the high-order aberration in designed optics was investigated and performed the correction of high-order effect using sextupole magnets.

Paper

Title

Other Keywords

Page

MOPFI025

Progress Towards High-Intensity Heavy-Ion Beams at RIKEN RIBF

ion, cyclotron, ECRIS, DTL

333

O. Kamigaito, T. Dantsuka, M. Fujimaki, T. Fujinawa, N. Fukunishi, H. Hasebe, Y. Higurashi, E. Ikezawa, H. Imao, T. Kageyama, M. Kase, M. Kidera, M. Komiyama, H. Kuboki, K. Kumagai, T. Maie, M. Nagase, T. Nakagawa, M. Nakamura, J. Ohnishi, H. Okuno, K. Ozeki, N. Sakamoto, K. Suda, H. Watanabe, T. Watanabe, Y. Watanabe, K. Yamada, H. Yamasawa
RIKEN Nishina Center, Wako, Japan

The RIKEN RIBF(Radioactive Isotope Beam Factory) accelerator complex has been designed and constructed to provide heavy-ion beams from D to U ions with the energy of 400 MeV/u to the maximum. Though the goal intensity is 1 particle μ amperes for the whole mass range, the intensities of very heavy-ions from Ca to U are still not satisfactory. In 2012, owing to the intensity upgrade of ⁴⁸Ca beams from ECR ion source, the beam current of ⁴⁸Ca was 400 pnA which was improved by factors of 2 in comparison with that in 2011. Since 2011, the new injector RILAC2 has been successfully commissioned and operated very stably for beam service time, increasing the U beam intensity by an order of magnitude. Because it was no longer realistic to use carbon foil to strip the charge of intense U beams, in 2012 the Low-Z gas stripper system instead of the standard carbon foil system has been introduced and successfully worked. To accelerate the ²³⁸U⁶⁴⁺ beams provided by the Low-Z gas stripper, modification of the following Fixed-frequency Ring Cyclotron was performed. In 2012, 15 pnA uranium beams which was four times larger than that provided in 2011 has been achieved.

MOPFI063

Progress on Designs for 180 MeV Injection into the ISIS Synchrotron

injection, dipole, septum, synchrotron

428

B. Jones, D.J. Adams, B.S. Drumm, M.C. Hughes, A.J. McFarland, C.M. Warsop
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

The ISIS Facility at the Rutherford Appleton Laboratory in the UK produces intense neutron and muon beams for condensed matter research. It operates at 50Hz accelerating beam via a 70 MeV H⁻ linac and an 800 MeV proton synchrotron, delivering a mean beam power of 0.2 MW. As an initial step towards megawatt operations at ISIS, a study of replacement of the existing injector with a new 180 MeV H⁻ linac has recently been completed. This could enable an increase in beam power to approximately 0.5 MW. The ISIS Facility at the Rutherford Appleton Laboratory in the UK produces intense neutron and muon beams for condensed matter research. It accelerates 3×10¹³ protons per pulse (ppp) at 50 Hz through a 70 MeV H− linac and an 800 MeV proton synchrotron, delivering a mean beam power of ~0.2 MW. A favoured first step to upgrade ISIS towards the megawatt regime is replacement of the linac with a new 180 MeV injector described in [1]. Studies of this upgrade, which aims to increase mean beam power up to 0.5 MW are outlined in [2]. This paper reports on recent development of the designs including the injection septum, dipole power supplies and detailed tracking of partially stripped foil products.

MOPME022

Beam Commissioning of Two Horizontal Pulse Steering Magnets for Changing Injection Painting Area from MLF to MR in the 3-GeV RCS of J-PARC

injection, beam-transport, emittance, target

518

P.K. Saha, H. Harada, N. Hayashi, H. Hotchi, M. Kinsho, T. Takayanagi, N. Tani
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
Y. Irie
KEK, Ibaraki, Japan
S. Kato
Tohoku University, Graduate School of Science, Sendai, Japan

We have been successfully commissioned two pulse steering magnets installed in the Linac to 3-GeV RCS (Rapid Cycling Synchrotron) injection beam transport (BT) line of J-PARC. RCS has to deliver a simultaneous as well as specific beam as demand by the downstream facilities of MLF (Material and Life Science Facility) and the MR (Main Ring). In order to obtain relatively a smaller transverse emittance at extraction, those magnets were designed to perform a smaller injection painting for the MR beam as compared to the MLF one. As stripper foil position is fixed for the charge exchange H⁻ injection, inclination of the injected beam centroid on foil for the MR beam is only moved to a smaller value by the pulse steering magnets, while DC septum magnets are fixed as determined first for the MLF beam. Their parameters were found to be very consistent with expectation and thus already in operation for switching to a painting area of 100 pi mm mrad for the MR beam as compared to that of 150 pi mm mrad for the MLF beam.

TUPWO009

Decoupling Capabilities Study of the Emittance Transfer Section

emittance, solenoid, quadrupole, coupling

1895

C. Xiao, O.K. Kester
IAP, Frankfurt am Main, Germany
L. Groening, O.K. Kester, M.T. Maier
GSI, Darmstadt, Germany

Flat beams are those which feature unequal emittances in the horizontal and vertical phase space. The present paper is on the planning of the experimental proof of principle. Detailed simulations of the experiment, initially based on linear matrix transformations, are performed. The remarkable flexibility of the set-up w.r.t. to decoupling is addressed, as it can provide an one-knob tool to set the horizontal and vertical emittance partitioning. It was found that the decoupling capability of the set-up is remarkably flexible and the impact and discussion of this finding is treated in a dedicated section

WEPEA034

Study on the Beam Dynamics in the RISP Driver Linac

linac, quadrupole, ion, resonance

2576

H.J. Kim, H.J. Jang, D. Jeon
IBS, Daejeon, Republic of Korea
J.G. Hwang
Kyungpook National University, Daegu, Republic of Korea
E.-S. Kim
KNU, Deagu, Republic of Korea

Abstract Rare Isotope Science Project (RISP) has been proposed as a multi-purpose accelerator facility for providing beams of exotic rare isotopes of various energies. The RISP driver linac which is used to accelerate the beam, for an example, Uranium ions from 0.3 MeV/u to 200 MeV/u consists of superconducting RF cavities and warm quadrupole magnets for focusing heavy ion beams. Requirement of the linac design is especially high for acceleration of multiple charge beams. In this paper, we present the requirements of dynamic errors and correction schemes to minimize the beam centroid oscillation and preserve beam losses under control.

THPPA01

Realization of New Charge-state Stripper for High-power Uranium Ion Beams

ion, target, acceleration, electron

3135

H. Imao
RIKEN Nishina Center, Wako, Japan

Recent works to realize the new charge-state stripper using recirculating helium gas are presented. Very limited lifetimes of conventional solid-state strippers due to huge dE/dx for very heavy ion beams (e.g., for uranium ions, several thousand times larger than protons at the energy around 10 MeV/u) were a principal bottleneck for their multi-stage acceleration at high intensities. The new stripping system is characterized by its infinite lifetime, efficient stripping and small beam degradation even for the world’s most intense uranium ion beams provided by the RIBF (more than 1 pμA at the injected energy of 11 MeV/u). Successful operations of the system in 2012 greatly contribute to the remarkable expansion of the accelerator performance of the RIBF that will allow an enormous breakthrough for exploring new domains of the nuclear world in the next several years; the peak intensity of the uranium beam has reached 15.1 pnA (almost 10¹¹ pps) at 345 MeV/u and the average intensity provided for the users has become ten times higher than it was in 2011.

Slides THPPA01 [6.535 MB]

THPFI011

Thermal Simulations of Charge-exchange Stripper Foils for High-melting-point Materials

simulation, injection, radiation, proton

3312

Y. Takeda
KEK, Ibaraki, Japan
M.A. Plum
ORNL, Oak Ridge, Tennessee, USA

Charge-exchange stripper foils can be very quickly broken by high-current beams. Hence, a long-lived foil that can withstand prolonged beam irradiation is eagerly awaited. It is well known that the maximum temperature of the foil plays an important role in the foil lifetime. Therefore, the temperature distribution map and the maximum temperature of the foils were investigated in detail by using simulation software of the finite element method and applications with ANSYS. Moreover, the heating properties of several kinds of high-melting-point materials were researched. According to the results, stripper foils of the same effective thickness showed drastically different maximum temperatures, differing by up to about 200 K. From these results, we show that the emissivity and specific heat of the foil considerably influences its maximum temperature.

THPWO010

Charge Stripping Tests of High Current Uranium Ion Beams with Methane and Hydrogen Gas Strippers and Carbon Foils at the GSI UNILAC

ion, heavy-ion, vacuum, target

3779

B. Schlitt, W.A. Barth, G. Clemente, L. Groening, M. Kaiser, B. Lommel, M.T. Maier, S. Mickat, J. Steiner, H. Vormann
GSI, Darmstadt, Germany

At the GSI UNILAC, a nitrogen gas stripper is routinely used for stripping of heavy ion beams at 1.4 MeV/u. Different approaches to optimize the stripping efficiency as well as different options to increase the ion charge states for delivery to SIS18 are being investigated. The existing gas stripper was operated with methane and hydrogen gas for stripping of high current uranium ion beams. The results as well as the limitations of these tests will be presented and will be compared to standard nitrogen operation of the gas stripper. In addition, newest results using differently prepared carbon stripping foils for the same ion beams will be reported.

THPWO038

Electron Stripping of High-intensity ²³⁸U Ion Beam with Recirculating He Gas

ion, electron, target, acceleration

3851

H. Imao
RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama, Japan
T. Dantsuka, M. Fujimaki, N. Fukunishi, H. Hasebe, O. Kamigaito, M. Kase, H. Kuboki, K. Kumagai, T. Maie, H. Okuno, T. Watanabe, Y. Watanabe, K. Yamada, Y. Yano
RIKEN Nishina Center, Wako, Japan

Next-generation in-flight RI beam facilities such as RIBF and FRIB pursue powerful and energetic ²³⁸U ion beams to produce thousands of new isotopes. For their efficient acceleration, a durable electron stripper in the intermediate energy region around 10-20 MeV/u is indispensable. However, there is no available stripper for the U beams with the intensity of more than 1 puA so far because of the lifetime problem of thin solid strippers caused by high energy loss. 　In the present study, a novel electron stripping system employing high-flow rate He gas circulation (200 L/min) has been developed. He gas with the thickness of 0.6 mg/cm² is confined and separated from beamline vacuum using five-stage differentially-pumped sections. To avoid huge gas consumption, a clean gas recycling is achieved with multi-stage mechanical booster pump array. The recycling rate of He gas was achieved as more than 99%. The system was successfully operated in user runs with U³⁵⁺ beams more than 1 puA injected at 10.8 MeV/u for the first time. U⁶⁴⁺ beams were stably delivered to subsequent accelerators with the stripping efficiency of 23% without any deterioration of the system.

THPWO065

Optics Design and Correction of High Order Aberration of the Charge Stripper Beam Line of RAON

sextupole, ion, emittance, optics

3906

H.J. Kim, D. Jeon, H.J. Kim
IBS, Daejeon, Republic of Korea
J.G. Hwang, E.-S. Kim
Kyungpook National University, Daegu, Republic of Korea

RAON (Rare isotope Accelerator Of Newness) in Korea will be providing the 400 kW of 238U⁷⁹⁺ beam with 8 puA and 200 MeV/u. One of the critical components of this project in the SCL is the design of the charge stripper. Between the two segments of the SCL, the charge stripper strips electrons from ion beams to enhance the acceleration efficiency in the following SCL2. For high efficiency of the acceleration and high power in SCL2, the optimum energy of striped ion in solid carbon foil stripper for SCL1 was estimated by using code LISE. The thickness of the solid carbon foil is 300 ug/m2. Based on this study, the charge stripping efficiency of solid carbon stripper is ~80 %. For the charge selection from ions which produced by the solid carbon stripper, the dispersive section is required in down-stream of the foil. The designed optics for dispersive section is based on the mirror-symmetric optics to minimize the effect of high-order aberration. And the high-order aberration in designed optics was investigated and performed the correction of high-order effect using sextupole magnets.