RIKEN, Wako, Saitama
The Radioactive Isotope Beam Factory at RIKEN Nishina Center is a next generation facility which is capable of providing the world’s most intense RI beams over the whole range of atomic masses. Three new ring cyclotrons have been constructed as post-accelerators for the existing facility in order to provide the intense heavy ion beam for the RI beam production by using a in-flight separation method. The beam commissioning of RIBF was started at July 2006 and we succeeded in the first beam extraction from the final booster cyclotron, SRC, by using 345 MeV/nucleon aluminum beam on December 28th 2006. The first uranium beam with energy of 345 MeV/nucleon was extracted from the SRC on March 23rd 2007. Various modifications for equipments and many beam studies were performed in order to improve the transmission efficiency and to gain up the beam intensity. Consequently, the world’s most intense 0.4 pnA 238U beam with energy of 345 MeV/nucleon and 170 pnA 48Ca beam with energy of 345 MeV/nucleon have been provided for experiments.
CAS/IMP, Lanzhou
Funding: Work supported by NSFC project 10635090.
CSR is a new ion cooler-storage-ring system in IMP, Lanzhou, China, which consists of a main ring (CSRm) and an experimental ring (CSRe) with two previous cyclotrons SFC (K=69) and SSC (K=450) as the injectors. The main construction of CSR was completed in 2005. It was being commissioned in the following two years. In 2008 the main purposes of CSR was focused on the primary 78Kr beam with kinetic energy up to 500MeV/u for precise mass spectroscopy at CSRe at isochronous mode. The cancer therapy phase-II in IMP with 100- 250MeV/u carbon beam from CSRm was tested and 6 patients with tumors in the heads were treated successfully.
MPI-K, Heidelberg
Several experiments at the heavy ion storage ring TSR have shown the feasibility of wide range, efficient acceleration and deceleration. The newly developed method of mass selective acceleration enables an effective separation of ion species with relative mass differences of ∆m/m = 3.7 · 10-4. Parabola shaped short bunch lengths were measured for an electron cooled 50 MeV 12C6+ ion beam in the space charge limit. To overcome the space charge limit the TSR was operated at a momentum compaction of α = 1.57.
RIKEN, Wako
A highly sensitive beam current monitor with an HTS (High-Temperature Superconducting) SQUID (Superconducting QUantum Interference Device) and an HTS current sensor, that is, an HTS SQUID monitor, has been developed for use of the RIBF (RI beam factory) at RIKEN. Unlike other existing facilities, the HTS SQUID monitor allows us to measure the DC of high-energy heavy-ion beams nondestructively in real time, and the beam current extracted from the cyclotron can be recorded without interrupting the beam user's experiments. Both the HTS magnetic shield and the HTS current sensor were dip-coated to form a Bi2 - Sr2 - Ca2 - Cu3 - Ox (Bi-2223) layer on 99.9 % MgO ceramic substrates. In the present work, all the fabricated HTS devices are cooled by a low-vibration pulse-tube refrigerator. These technologies enabled us to downsize the system. Prior to practical use at the RIBF, the HTS-SQUID monitor was installed in the beam transport line of the RIKEN ring cyclotron to demonstrate its performance. As a result, a 20 μA 40Ar15+ beam intensity (63 MeV/u) was successfully measured with a 500 nA resolution. Despite the performance taking place in an environment with strong gamma ray and neutron flux radiations, RF background and large stray magnetic fields, the measurements were successfully carried out in this study. This year, the HTS SQUID monitor was upgraded to have aresolution of 100 nA and was reinstalled inthe beam transport line, enabling us to measure a 4 μA 132Xe20+ (10.8 MeV/u) beam and a 1 μA 132Xe41+ (50.1 MeV/u) beam used for the accelerator operations at RIBF. Hence, we will report the results of the beam measurements an the present status of the HTS SQUID monitor.
JYFL, Jyväskylä
Funding: This work has been supported by the Academy of Finland under the Finnish Centre of Excellence Programme 2006-2011 (Nuclear and Accelerator Based Physics Programme at JYFL).
The accelerator based experiments at JYFL (University of Jyväskylä, Department of Physics) range from basic research in nuclear physics to industrial applications. A substantial share of the beam time hours is allocated for heavy ion beam cocktails, used for irradiation tests of electronics. Producing the required ion beam cocktails has required active development of the JYFL ECR ion sources. This work is briefly discussed together with the implications of the beam cocktail campaign to the beam time allocation procedure. The JYFL ion source group has conducted experiments on plasma physics of ECR ion sources including plasma potential and time-resolved bremsstrahlung measurements, for example. The plasma physics experiments are discussed from the point of view of beam cocktail development.
BNL, Upton
Funding: Work supported under the auspices of the US Department of Energy and the National Aeronautics and Space Administration.
At Brookhaven National Laboratory, a high current Electron Beam Ion Source (EBIS) has been developed as part of a new preinjector that is under construction to replace the Tandem Van de Graaffs as the heavy ion preinjector for the RHIC and NASA experimental programs. This preinjector will produce milliampere-level currents of essentially any ion species, with q/A≥ 1/6, in short pulses, for injection into the Booster synchrotron. In order to produce the required intensities, this EBIS uses a 10A electron gun, and an electron collector designed to handle 300 kW of pulsed electron beam power. The EBIS trap region is 1.5 m long, inside a 5T, 2m long, 8” bore superconducting solenoid. The source is designed to switch ion species on a pulse-to-pulse basis, at a 5 Hz repetition rate. Singly-charged ions of the appropriate species, produced external to the EBIS, are injected into the trap and confined until the desired charge state is reached via stepwise ionization by the electron beam. Ions are then extracted and matched into an RFQ, followed by a short IH Linac, for acceleration to 2 MeV/A, prior to injection into the Booster synchrotron. An overview of the preinjector is presented, along with experimental results from the prototype EBIS, where all essential requirements have already been demonstrated. Design features and status of construction of the final high intensity EBIS is also be presented.
Goethe Universität Frankfurt/IAP, Frankfurt
MSU/NSCL, East Lansing
ECR and EBIS have become well-known ion sources for most heavy ion accelerator projects. The basic difference arises from the method, how energy is provided to create dense energetic electrons: An ECR uses microwave heating of a magnetically confined plasma, while in an EBIS the energy comes from a power supply to accelerate an electron beam and focus it to high density in a strong solenoidal magnetic field. Basically ECR sources are dc sources of heavy ions but the afterglow extraction also provides intense mA pulses in ms. In contrast to this EBIS sources provide an intense ion pulse in 1-100 μs and therefore find application in feeding synchrotrons. This determines most of the accelerator applications: ECR sources have very successfully extended the range (and life) of cyclotrons, while EBIS has found application at high energy facilities. For radioactive beam facilities, both kind of sources are in use. ECR sources in the trapping mode (ECRIT) perform the ionization (charge breeding) of high intensity primary beams, while EBIS can reach higher charge states at lower emittance, which provides an improved signal to noise ratio for rare isotopes.
Michigan University/MIBL, Ann Arbor
The Michigan Ion Beam Laboratory (MIBL) at the University of Michigan has instruments equipped with ion sources capable of generating a wide variety of ions. The 1.7-MV Tandem accelerator can operate with three different sources: a Torvis source, a Duoplasmatron source and a Sputter source. The 400-kV ion implanter is equipped with a CHORDIS source that can operate in three different modes (gas, sputter, and oven) and is capable of producing ion beams for most of the elements in the periodic table. In this work, we discuss the principle of operation of each source, their performances and the latest applications and projects conducted at MIBL using these sources.
CNAO, Milano
INFN/LNF, Frascati
The Centro Nazionale di Adroterapia Oncologica (CNAO) is the first Italian center for deep hadrontherapy, namely an innovative type of oncological radiotherapy using hadrons. The CNAO machine installation is in progress and alternates with lines commissioning, started in the Summer 2008. The present paper reports about Beam Diagnostics (BD) choices, status and post-commissioning evaluation, as concerns the Low Energy Beam Transfer (LEBT) line monitors.
CERN, Geneva
Electron cooling is central in the preparation of dense bunches of lead beams for the LHC. Ion beam pulses from the Linac3 are transformed into short high-brightness bunches using multi-turn injection, cooling and accumulation in the Low Energy Ion Ring, LEIR. The LEIR cooler was the first of a new generation of coolers utilising high-perveance variable-density electron beams for the cooling and accumulation of heavy ion beams. It was commissioned in 2006 at the same time as the LEIR ring and has since been used to provide lead ions for the commissioning of the LHC injector chain. We report briefly on the status of the LHC ion injector chain and present results of measurements made to check and to better understand the influence of the electron beam size, intensity and density profile on the cooling performance. Future plans to improve the performance of the device will also be presented.
JINR, Dubna
Accelerated 12C ion beams are effectively used for cancer treatment at various medical centers, in particular to treat patients with radio resistant tumors. On the other hand, positron emission tomography is the most effective way of tumor diagnostics. The intensive 11C ion beam could allow both these advantages to be combined. It could be used both for cancer treatment and for on-line positron emission tomography. Formation of a primary radioactive 11C6+ ion beam with the intensity of 1010-1011 pps from the ion source may allow cancer treatment and on-line dose verification. 11C isotope is produced in the nuclear reaction 14N (p,α)11C using the gas target chamber irradiated by a proton beam. If the nitrogen target chamber contains about 5% of hydrogen, approximately 1014 methane molecules 11CH4 can be produced each 20 minutes. The separated radioactive methane can be loaded into an ion source. The methodology and technique of formation of high-intensity radioactive carbon beams were tested in the JINR electron string ion source (ESIS) Krion-2 using usual non radioactive methane. The measured conversion efficiency of methane molecules to carbon ions appeared to be rather high, 15 % for C6+ ions and 25% for C4+ ions. The developed technique of pulsed methane loading and the experimentally obtained conversion efficiency permit obtaining primary radioactive 11C6+ beams at the intensity of 1010 -1011 pps and performing cancer treatment and online dose verification.
JINR, Dubna
VNIIEF, Sarov
The so-called reflex mode of Electron String Ion Source (ESIS) operation has been under intense study, both experimental and theoretical at JINR during the last decade. The idea of using a tubular electron string ion source (TESIS) has been put forward recently to obtain 1- 2 orders of magnitude increase in the ion output as compared with ESIS. The project is aimed at creating TESIS and studying an electron string in the tubular geometry. The new tubular source with a superconducting solenoid up to 5 T should be constructed in 2010. The method of the off-axis TESIS ion extraction will be used to get TESIS beam emittance comparable with ESIS emittance. It is expected that this new TESIS (Krion T1) will meet all rigid conceptual and technological requirements and should provide an ion output approaching 10 mA of Ar16+ ions in the pulse mode and about 10 μA of Ar16+ ions in the average current mode. Analytical, numerical study of the tubular electron strings and the design of the TESIS construction are given in this report. The experiments with quasi tubular electron beams performed on the modified ESIS Krion 2 are also discussed there.
NSC/KIPT, Kharkov
New properties of vacuum discharges in magnetic field with unconventional discharge gaps at low pressure up to high vacuum are briefly described. Both single- and multi-charge ion sources may be developed on basis of such new discharge modes. Such ion sources may have advantages in comparison with conventional ones. The main advantages are the long lifetime due to the absence of filaments and arc spots, high energy and gas efficiency due to high plasma electron temperature. The development of the discharge research and recent results are discussed.
INFN/BA, Bari
BINP, Novosibirsk
Bari University INFN/BA, Bari
The charge breeding technique is used for Radioactive Ion Beam (RIB) production in the Isotope Separation On Line (ISOL) method in order of optimizing the reacceleration of the radioactive elements produced by a primary beam in a thick target. In some experiments a continuous RIB of certain energy could be required. The EBIS based charge breeding device cannot reach a real CW operation because the high charge state ions produced are extracted by the same part where the 1+ ions are injected, that is, from the electron collector. In this paper, an hollow cathode e-gun for an EBIS in charge breeding operation has been presented. Furthermore, a preliminary system design to inject the 1+ ions from the cathode part will be also shown. In this way, the ions extraction system, placed in the electron beam collector, can be left only to extract the n+ ions, and then the CW operation, at least in principle, could be reached.
TU Dresden, Dresden
DREEBIT, Dresden
Siemens AG, Erlangen
Funding: Work supported by the EFRE fund of the EU and by the Freistaat Sachsen (Project Nos. 12321/2000 and 12184/2000) and Siemens AG.
The technical performance of ion sources of the Electron Beam Ion Source (EBIS) type has substantially improved during the last years. This is demonstrated by proof-of-principle experiments which have been done using a room temperature EBIS, a so-called Dresden EBIS-A, which has been in use for several years. A new superconducting EBIS, a so-called Dresden EBIS-SC, has been taken into operation. With the expected higher beam intensities the Dresden EBIS-SC will offer a compact and low-cost solution for applications in particle therapy and will be applicable for synchrotron based solutions (single- or multi-turn injection) as well as other accelerator schemes. It is shown that the introduction of the Dresden EBIS-SC will simplify the injection beam line of medical accelerator facilities.