In the framework of the program on medical applications a compact 750 MHz RFQ has been designed and built to be used as an injector for a hadron therapy linac. This RFQ was designed to accelerate protons to an energy of 5 MeV within only 2 m length. It is divided into four segments and equipped with 32 tuners in total. The length of the RFQ corresponds to 5λ which is considered to be close to the limit for field adjustment using only piston tuners. Moreover the high frequency, which is about double the frequency of existing RFQs, results in a sensitive structure and requires careful tuning. In this paper we present the tuning algorithm, the tuning procedure and rf measurements of the RFQ.

After 30 years of operation, the Cockcroft-Walton based injector at the Fermi National Accelerator Laboratory has been replaced by a new beam line including a dimpled magnetron 35 keV source in combination with a 750 keV four-rod radio frequency quadrupole (RFQ). The new injector is followed by the existing drift tube linac. Prior to installation, a test beam line was built which included the magnetron source and the four-rod RFQ with a number of beam measurement instrumentation. The first beam test with the RFQ showed an output energy deviation greater than 2.5%. Other problems also showed up which led to investigations of the output energy, power consumption and transmission properties using rf simulations which were complemented with additional beam measurements. The sources of this deviation and the mechanical modifications of the RFQ to solve this matter will be presented in this paper. Meanwhile, the nominal output energy of 750 keV has been confirmed and the new injector with the four-rod RFQ is in full operation.

In the framework of the NICA project for the development of an accelerator collider facility at the LHEP JINR, Dubna, the design and commissioning of two injectors are under way. The Heavy Ion Linear accelerator (HILAC) is intended to inject the gold ions into the superconducting synchrotron Booster and designed to accelerate particles with a charge-mass ratio Z/A ≥ 0.16 up to an energy of 3.2 MeV u−1. HILAC in 2015 installed in the workplace in the hall of the injection facility. In 2018, a series of tests on HILAC commissioning had been done to measure the energy and estimate transmission of accelerated beams of the carbon ions from the laser ion source. The Light Ion Linear accelerator (LILAC) is intended for injection into the superconducting synchrotron Nuclotron the polarized deuterons and protons, as well as the light ions from LIS and is in the design stage for accelerating particles with a charge-mass ratio of Z/A ≥ 0.33 to 7 MeV/u. The stable beam intensity from LIS is strongly desirable for the tasks listed above. The article describes the use of the beams from a laser ion source based on an Nd:YAG laser in the injection facility and presents a method for solving the problem of beam instability due to uncontrolled emission caused by reflected radiation.

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