RIKEN, Wako, Saitama
In 2008, the RIKEN RI-Beam Factory (RIBF) succeeded in providing heavy ion beams of 48Ca and 238U with 170 particle-nano-ampere and 0.4 particle-nano-ampere, respectively, at an energy of 345 MeV/u. The transmission efficiency through the accelerator chain has been signifcantly improved owing to the continuous efforts paid since the first beam in 2006. From the operational point of view, however, the intensity of the uranium beam should be much increased. We have, therefore, constructed a superconducting ECR ion source which is capable of the microwave power of 28 GHz. In order to reduce the space-charge effects, the ion source was installed on the high-voltage terminal of the Cockcroft-Walton pre-injector, where the beam from the source will be directly injected into the heavy-ion linac by skipping the RFQ pre-injector. The test of the ion source on the platform has started recently with an existing microwave source of 18 GHz. This pre-injector will be available in October 2009. We will show further upgrade plan of constructing an alternative injector for the RIBF, consisting of the superconducting ECR ion source, an RFQ, and three DTL tanks. An RFQ linac, which has been originally developed for the ion-implantation application will be reused for the new injector. Modification of the RFQ as well as the design study of the DTL are under progress. The new injector, which will be ready in FY2010, aims at independent operation of the RIBF experiments and super-heavy element synthesis.
TRIUMF, Vancouver
ISAC is the TRIUMF facility for the production and post acceleration of Rare Isotope Beams (RIBs). The post acceleration section includes two normal conducting linacs, an RFQ injector and a variable energy IH-DTL, and a superconducting linac composed of five cryomodules each containing four quarter wave bulk niobium resonators. All three machines operate CW. The RFQ and DTL deliver beam since 2000 to a medium energy area with energies variable between 150 keV/u and 1.8 MeV/u. The superconducting linac, with an effective voltage of 20 MV started delivering in 2007 with performances exceeding design specifications reaching final energies up to 11 MeV/u for lighter particles. The linac gradients show no average degradation in performance. Well established operational and tuning procedures allow reliable operations. Schemes have been developed to effectively deliver the very low intensity (as low as few hundred particles per second) radioactive ion beams. The superconducting linac will be upgraded with the addition of twenty more cavities (boosting the acceleration voltage to 40 MV) by the end of 2009 making the reliability quest more challenging. In this paper we present past, present and planned operations with the ISAC linacs.
INFN/LNL, Legnaro
GSI, Darmstadt
CNAO, Milan
INFN/LNF, Frascati
INFN/LNS, Catania
The CNAO (Centro Nazionale di Adroterapia Oncologica), located in Pavia (Italy), is a dedicated clinical synchrotron facility for cancer therapy using high energy proton and Carbon beams. The 400 MeV/u synchrotron is injected by a 216.8 MHz 7 MeV/u linac composed by a low energy beam transport (fed by two ion sources), a 400 keV/u 4-rod type RFQ and a 20 MV IHDTL. The commissioning of the two ECRIS ion sources and the low-energy line was successfully completed at the end of January 2009 reaching the proper beam conditions for injection into the RFQ. After installation and conditioning, the RFQ was commissioned with beam by the GSI-CNAO-INFN team in March 2009. The beam tests results are presented and compared to the design parameters.
GSI, Darmstadt
The GSI linear accelerator UNILAC and the synchrotron SIS18 will feed the future accelerator facility FAIR (Facility for Antiproton and Ion Research) with heavy ion beams. Several hardware measures at the UNILAC are necessary to meet the FAIR requirement, implicating a beam intensity of 3.2·1011 of U28+-particles within an UNILAC macro pulse of 100μs length and defined emittance space at SIS18 injection. The stripper gas jet density was strongly increased to get the equilibrium charge state even for the heaviest ions. A procedure matching the 6-D-phase space for proper A lvarez DTL injection and increase of the transverse phase advance in the Alvarez accelerators reduces emittance growth. In front of SIS18 injection a new separator provides an immediate selection of the desired charge state after stripping and therefore reduces space charge induced emittance growth. The front-end of the high current injector includes several bottle necks. A compact solenoid channel is planned providing straight line injection into the 4-rod- RFQ. The RFQ will be equipped with new designed electrodes for increased acceptance and reduced emittance growth. The contribution gives an overview of end-to-end simulations, the different upgrade measures, the particular beam investigations, and the status of beam development satisfying FAIR requirements.
TRIUMF, Vancouver
At the ISAC facility in TRIUMF radioactive ion beams (RIB) are produced using the ISOL method and post accelerated. The post accelerator chain consists of a radio frequency quadrupole (RFQ) injector followed by a drift tube linac (DTL) that accelerates the ions from 150 keV/u up to 1.8 MeV/u. A further stage of acceleration is achieved using a superconducting linac where the beam is injected using the DTL and the energy boosted with 20 MV of acceleration voltage (increased to 40MV by the end of 2009). The possibility of decelerating the beam maintaining good beam quality using the DTL is investigated based on experimenters request to reach energies lower than 150 keV/u. The beam dynamics simulation using the LANA code are compared with on line measurements. In this paper we will report the results of the investigation that aims to establish the lowest energy we can deliver in the post accelerator section of the ISAC facility.