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LITHIUM AND BORON BEAM ACCELERATION THROUGH LINAC AT PLF, MUMBAI V. Nanal, R.G. Pillay, S. Pal, J.N. Karande, P. Dhumal, M.S. Pose, C. Rozario, M.E. Sawant, A.N. Takke, A.A. Shinde, R.D. Deshpande, S.R. Sinha, A. Singh and S.P. Singh Pelletron Linac Facility, TIFR, Mumbai – 400005. Abstract The superconducting LINAC booster at PLF has been designed for A=12-60 and has been operational since 2007. Several experiments have been carried out using beams of 12C to 35Cl. The QWR cavity is designed for β0=0.1 and hence it is difficult to accelerate lighter beams. Moreover, the low energy buncher system is not suitable for beams lighter than 12C. Due to growing interest in studying light ion (6,7Li, 10,11B) induced reactions on fissile targets at energies higher than the available energy from the Pelletron, we have recently accelerated beams lighter than Carbon. The ion source deck was operated at lower voltage (100-125 KV) for matching lighter beams with low energy buncher. Both 7Li and 11B of E~5 MeV/A obtained from the Pelletron were accelerated through LINAC to E~8 MeV/A. The energy gain for individual resonators was found to be consistent with measured field values after correcting for transit time factor. During the acceleration test with these light beams, detail radiation dose mapping of the accelerator area and surrounding area was carried out and found to be well within permissible limits. Thereafter beams were successfully delivered at target stations for experiments with an intensity of 4-8 pnA. BEAM ACCELERATION Figure 1 shows layout of the LINAC. Timing characteristics of the beam is monitored at entrance of LINAC Phase I and Phase II, marked as Lin1 and Lin4 in the Fig. 1. The ion source deck was operated at lower voltage (100-125 KV) for matching lighter beams with low energy buncher. Both 7Li and 11B of E~5 MeV/A obtained from the Pelletron were accelerated through LINAC to E~8 MeV/A. The energy gain for individual resonators was found to be consistent with measured field values after correcting for transit time factor. INTRODUCTION The superconducting LINAC booster, indigenously developed to boost the energy of the heavy ion beams from the 14 MV Pelletron accelerator at TIFR, Mumbai, has been fully operational since July 2007 [1]. The LINAC consists of seven modular cryostats, each housing four lead plated quarter wave resonators, designed for an optimum velocity β0=0.1 at an operating frequency of 150 MHz. Several experiments have been carried out using beams of 12C, 16O, 19F, 28,30Si, 31P, 32S, 35Cl. It is difficult to accelerate lighter beams and achieve good transmission at target since for lighter beams β very quickly exceeds the optimum velocity β0. Due to growing interest in studying light ion (6,7Li, 10,11B) induced reactions at higher energies and given the operational limitations of Pelletron (12 MV), we have recently extended LINAC operations to lighter beams [2] and accelerated 7Li and 11B beam. Figure 1: Layout of LINAC indicating positions of timing detectors at entrance of Phase I and Phase II Time spectra measured with 1” BaF2 during the Boron beam acceleration at Lin1 (Phase I entry), at Lin4 (Phase II entry) and at user station are shown in Figure 2. The measured FWHM (<1 ns) is inclusive of detector resolution. Nearly identical time structure of at Lin1 and Lin4, not only ensured good acceptance in phase II but also resulted in good transmission. Both Lithium and Boron beams were successfully delivered at target stations for experiments with an intensity of 4-8 pnA. During the acceleration test with these light beams, detail radiation dose mapping of the accelerator area and surrounding area was carried out and found to be well within permissible limits. The operational limit of E≤8 MeV/A with a maximum of 10 pnA current at target has been imposed from the radiation safety considerations. SUMMARY The LINAC operations have been successfully extended to beams lighter than A=12. The ion source deck voltage is lowered for better matching of lighter beams into low energy buncher. Starting with E~5 MeV/A 7Li and 11B beam from the Pelletron, were accelerated through LINAC to E~8 MeV/A and were successfully delivered at target stations for experiments. The operational limit of E≤8 MeV/A with a maximum of 10 pnA current at target has been imposed from the radiation safety considerations. ACKNOWLEDGMENT We would like to thank the Pelletron-LINAC staff, DNAP, Low Temperature Facility, Central Workshop and Electronics Division (BARC) for their support. REFERENCES [1] R.G. Pillay, Figure 2: Time structure of 11B beam at various locations measured with BaF2. “Overview of the Pelletron Linac Facility”, InPAC2011 proceedings. [2] V. Nanal et al.,“Extension of Superconducting LINAC Operation to Lighter Beams”, http://accelconf.web.cern.ch/AccelConf/HIAT2012/pa pers/po06.pdf