Acceleration of He⁺ Beams for Injection Into NICA Booster During its First Run

Heavy Ion Linear Accelerator (HILAC) is designed to accelerate the heavy ions with ratio A/Z ≤ 6.25 produced by ESIS ion source up to the 3.2 MeV for the injection into superconducting synchrotron (SC) Booster. HILAC was commissioned in 2018 using the carbon beams from Laser Ion Source (LIS). The project output energy was verified. Transmission could be estimated only for DTL structure because of the presence at the RFQ input the mixture of ions with different charge states extracted from laser plasma. To estimate transmission through the whole linac the ion source producing the only species He+ was designed. The beams of He+ ions were used for the first run of SC Booster. Design of the helium ion source and results of the He+ beam acceleration and injection are described. HEAVY ION LINEAR INJECTOR Heavy ion linear accelerator (HILAC) is proposed to be injectors for SC Booster synchrotron of the NICA facility. The main features of it are presented in the Table 1. Table 1: Main Features of HILAC HILAC Species of ions Au31+ Z/A ≥ 0.16 Input energy 17 keV/u Output energy 3.2 MeV/u Beam current, mA 10 Operating frequency, MHz 100.625 Beam transmission rate, % 98 The accelerator is based on 4-rod RFQ [1] and IH DTL cavities with the KONUS accelerating structure inside [2]. The Heavy Ion Linear accelerator (HILAC) is to inject the gold ions into the superconducting synchrotron Booster and designed to accelerate particles with a ratio A/Z ≤ 0.16 up to energy 3.2 MeV/u. In 2015-2018, HILAC commissioning had been done [3, 4]. The carbon beams С2+, С3+, С4+, С5+ и С6+ were accelerated and measured energy of accelerated carbon ions was in good agreement with the design value of 3.2 MeV/u. Beams transmission through DTL structure was estimated ~65% [3, 4]. To estimate transmission through the whole linac the only species of ions should be injected in RFQ. On that reason the ion source producing the only He+ ions was developed and assembled.