GSI, Darmstadt
IAP, Frankfurt am Main
The GSI linear accelerator UNILAC provides heavy ion beams at Coulomb barrier energies for search and study of super heavy elements. Typical cross-sections of 55 fb require beam doses of 1.4·1019 according to a beam time of 117 days. Several upgrades will reduce the beam time to only 16 days. A second injection branch with a 28GHz-MS-ECRIS anticipates a factor of 10 in particle intensity. By a new cw rfq-structure all accelerator tanks are suitable for a duty cycle of at least 50% instead of 25% presently. Due to this, thermal power increase of 19 rf-amplifiers eased by higher ion charge states of the ECRIS is necessary. Finally the UNILAC timing system controlling 50Hz pulse-to-pulse operation of up to six beams differing in ion species and energy has to be modified considering beam diagnostics electronics and pulsable magnets. The front end comprising ECRIS, rfq- and IH-structure is cw suitable and will serve as injector for a new future sc-cw-linac.
HIT, Heidelberg
The Heidelberg Ion Beam Therapy Centre (HIT) is the only medical facility in Europe for cancer treatment with protons and carbon ions. To broaden the range of available ion species towards helium the low energy beam transport (LEBT) will be extended by a third ion source and the associated spectrometer section. Following a novel ion optical approach the LEBT-branch has been redesigned. A dedicated test bench will be used to commission and validate the new design prior to its integration into the medical accelerator. In its final stage the test bench will comprise an ECR-ion source, a LEBT and an RFQ with diagnostics line. It opens up the unique opportunity to perform comprehensive investigations not only of the ion source but also of other devices like the RFQ which have been optimised in the frame of the LINAC upgrade. Here, particular emphasis will be placed on the new design of the analyser dipole and the macro pulse chopper. Furthermore results of beam optical simulations and first measurement results will be presented.
IHEP Beijing, Beijing
Work on the Chinese Spallation Neutron Source (CSNS) has been progressing well, including successful prototyping of some of the key components of the facility. The source incorporates an H- linac, with an output energy upgradable from 81 to 250 MeV. The status of the project will be described.
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
Beam commissioning of the J-PARC linac started in November 2006 and 181 MeV acceleration was successfully achieved in January 2007. The linac had delivered beams for commissioning of accelerators and experimental facilities. Trip rates of the RFQ, however, unexpectedly increased in Autumn 2008, and that was the primary limitations of the operation days and power ramp up. We tried to recover by improvement of vacuum properties, tender conditioning and so on. By taking these measures, we can lengthen the continuous operation days and stand user operations. We ramped up the beam power from 20 kW to 120 kW for 3 GeV beam users in November 2009. This corresponds to the linac beam power of 7.2 kW and the linac has delivered beams at this power since then without significant troubles. And also we successfully demonstrated 300 kW at 3 GeV for 1 hour in December. We present the performance and operation experiences of the J-PARC linac.
Imperial College of Science and Technology, Department of Physics, London
University of Warwick, Coventry
STFC/RAL/ISIS, Chilton, Didcot, Oxon
STFC/RAL/ASTeC, Chilton, Didcot, Oxon
In order to contribute to the development of high power proton accelerators in the MW range, to prepare the way for an ISIS upgrade and to contribute to the UK design effort on neutrino factories, a front end test stand (FETS) is being constructed at the Rutherford Appleton Laboratory (RAL) in the UK. The aim of the FETS is to demonstrate the production of a 60 mA, 2 ms, 50 pps chopped beam at 3 MeV with sufficient beam quality. The status of the FETS will be given and experimental results from the commissioning of LEBT and ion source will be presented. Previous measurements showed that the emittance of the beam delivered by the ion source exceeded our expectations by more than a factor of 3. Since then various changes in the beam extraction/post accelerator region reduced the beam emittance more than a factor of 2. The results from measurements will be compared with numerical simulations of the particle dynamics from the ion source to the end of the MEBT and the results discussed in respect to further work.
IAP, Frankfurt am Main
NTG, Gelnhausen
The IH-type RFQ for the MAFF project at the LMU in Munich was operated at a beam test stand at the IAP in Frankfurt. It is the second IH-RFQ after the HIS at GSI and it has been designed to accelerate rare isotope beams (RIBs) with mass to charge ratios A/q up to 6.3 from 3 keV/u to 300 keV/u at an operating frequency of 101.28 MHz with an electrode voltage of 60 kV. Experimental results such as shunt impedance, energy spectrum and transmission will be presented.
IMP, Lanzhou
IAP, Frankfurt am Main
BNL, Upton, Long Island, New York
A compact RFQ for carbon ion beam from a Laser-ion souce is being tested in IMP, Lanzhou. It is the first example of LINAC structures for IMP. Testing schemes and first results are presented.
IMP, Lanzhou
IAP, Frankfurt am Main
BNL, Upton, Long Island, New York
A RFQ has been designed and built for research of direct plasma injection scheme (DPIS), which can provide high current and highly charged beams. Because of the strong space charge forces of beam from laser ion source, the beam dynamics design of the RFQ was carried out with a new code LINACSrfq which can treat space charge effectively due to equipartitioning design strategy. Another feature of the RFQ is its high energy gain in two-meter long which will be described in detail. Construction of the RFQ cavity and the 100MHz/250kW amplifier has been completed and ready for test. A laser ion source is being tested. The assembling of the whole system including the ion source, the RFQ, the beam analyzing and diagnostic system is being done. Preliminary test results will be presented.
Fermilab, Batavia
The Fermilab High Intensity Neutrino Source program has built and commissioned a pulsed 325 MHz RFQ. The RFQ has successfully accelerated a proton beam at the design RF power. Experiences encountered during RFQ conditioning, including the symptoms and cause of a run-away detuning problem, and the first beam results are reported.
KAERI, Daejon
A Radio Frequency Quadrupole (RFQ) has being desinged for the post-acceleration of radio isotope beams from a radio isotope beam production system such as an isotpe separation on line (ISOL) or an in-flight separation. For simple and efficient beam acceleration, a chrage breeding system such as an electron cyclotron resonance ion source (ECRIS) or electron beam ion source (EBIS) The RFQ will operate at a resonant frequency of 70MHz at cw mode, and accelerate the beams to 300keV/nucleon. In the conference we will present the design of the RFQ.
ANL, Argonne
An emittance meter based on a pepper-pot coupled to a CsI (Tl) scintillator has been developed over the last several years [1] at Argonne National Laboratory. A compact version of such a probe for on-line emittance measurements has been designed, built and installed into the low energy beam transport (LEBT) line of the Argonne Tandem Linac Accelerator System (ATLAS) and also downstream of the gas catcher of the recently commissioned Californium Rare Isotope Breeder Upgrade (CARIBU). The probe has demonstrated the capability to measure emittance of ion beams with a current density as low as 10 nA/cm2. Systematic emittance measurements in the ATLAS LEBT for different ion species have been done and results will be presented. The probe, based on a pepper-pot coupled to an MCP viewing system, has been designed and built to measure the emittance of low intensity (102-106 ions/s) radioactive CARIBU ion beams.
[1] S. Kondrashev et al. Development of a pepper-pot emittance probe and its application for ECR ion beam studies. Nuclear Instruments and Methods in Physics Research A 606, 2009, pp. 296-304.
CEA, Gif-sur-Yvette
New PIC ray-tracing methods allows to design and simulate the transport of high intensity proton, H- and deuteron beam in the LEBT systems of future facilities like FAIR Proton Linac or IFMIF-EVADA and SPIRAL2 deuteron linacs. These techniques enable a precise prediction of the effect of residual gas ionisation and the consequent neutralisation of the large beam space charge on the beam emittances.
LANL, Los Alamos, New Mexico
JYFL, Jyvaskyla
The Los Alamos Neutron Sciene Center (LANSCE) accelerator facility has the capability of accelerating both H+ and H- ion beams. LANSCE H- User Programs rely on the ion source's ability to deliver an appropriate beam current within a given emittance limit. An active H- ion source development program is ongoing with the goal of improving source performance (e.g. reliability, availability, increased out current, etc.) The formation of H- ions in the LANSCE negative ion source occurs on the surface of a negatively biased electrode (converter), exposed to a flux of positive ions incident from a cusp-confined, filament-driven discharge. The source typically delivers a 16 mA pulsed (60 Hz) H- beam with a source lifetime of 35 days. A program to reach 28-35 mA with the LANSCE source is outlined. It includes efforts to improve filament performance, elevating source body temperatures, optimizing converter geometry and location, optimizing converter cooling, and increasing the number of filaments from two to three.
IHEP Beijing, Beijing
STFC/RAL, Chilton, Didcot, Oxon
The type of the H- ion source foe CSNS is a Penning Surface Plasma Source (SPS). The output energy of the source is 50keV and the pulsed current of H- beam is 20mA with a rms. emittance of 0.2π mm.mrad. The construction of H- ion source test stand for CSNS is finished and commissioning of the source is being done. Up to now, stable H- ion beam with a current up to 45mA and energy of 50keV is achieved. Emittance measurements of the beam is also being prepared.
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
J-PARC, KEK & JAEA, Ibaraki-ken
A cesium-free negative hydrogen ion source driven with a LaB6 filament is being operated for J-PARC. The beam commissioning of J-PARC accelerators started in November 2006. As of April 2010, there have been 32 beam commissioning or supply runs. In these runs, the ion source has been successfully operated in two different modes such as low current mode of 5 mA and high current mode of 30 mA. According to the task of the run, one of the two modes was selected. However, the beam current has been restricted to less than 15 mA for the stable operation of the RFQ linac which has serious discharge problem from September 2008. The beam run is performed during 4-5 weeks cycles, which consisted of a 3-4 weeks beam run and 4 days down-period interval. At the recent beam run, approximately 700 hours continuous operation was achieved, which is satisfied with the requirement of the ion source lifetime for the J-PARC first stage. At every runs, the beam interruption time due to the ion source failure is several hours, which correspond to the ion source availability of 99 %.
ORNL, Oak Ridge, Tennessee
The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory is in the process of ramping up the H- ion beam power to 1.4 MW, its full design power for the neutron production. For robust operation of the neutron facility, work is underway for various improvements on the RF power systems of the ion source. For short and long-term higher beam power operations, an RF-driven H- ion source employing external antenna with a water-cooled, ceramic aluminum nitride (AlN) plasma chamber has been developed*. The new ion source has been tested to deliver up to 42 mA in the SNS Front End (FE) and unanalyzed beam currents up to ~100mA (60Hz, 1ms) in the ion source test stand. In addition to the external antenna design for improved antenna lifetime, other RF developments for improvement of reliability are running 2 MHz power amplifier system is with isolation transformer, employing full solid-state 2 MHz power amplifier, more precise 2 MHz capacitive impedance matching, and upgrading 13 MHz RF plasma gun system. This paper discusses the engineering solutions with analysis and development of the above RF systems for the new ion source system.
R.F. Welton, N.J. Desai, J. Carmichael, B. Han, Y.W. Kang, S.N. Murray, T. Pennisi, M. Santana, and M.P. Stockli, "The Continued Development of the SNS External Antenna H- Ion Source," ICIS2009