Operational Status and Future Plan of Proton Linear Accelerator at KOMAC

Since the second half of 2013, Korea Multi-purpose Accelerator Complex (KOMAC) has been supporting user beam service by using a 100-MeV proton linac and several beam line facilities. Proton beam service fields include various applications and research programs, such as material science, bio-medical science, semiconductor applications as well as nuclear physics and basic science. The 100-MeV linac is composed of an injector based on a 50-keV microwave ion source and two-solenoid LEBT (low energy beam transport), a 3-MeV RFQ with four-vane structure and conventional drift tube linac (DTL), where proton beam is accelerated from 3 MeV to 100 MeV. As the operation period of the proton accelerator exceeds 10 years and the cumulative operating time surpasses 30,000 hours, we judge that it is an opportune time to establish a long-term plan to prepare for the aging of the accelerator. To replace the currently operating RFQ, which shows degradation in performance (especially the beam transmission), we design a new RFQ with some modifications. For DTL, we are supposed to change the quadrupole magnet inside each drift tube from electromagnet type to permanent magnet type because the electromagnet has shown some trouble in view of long term stability. To leap forward in device and utilization technologies, we complete the construction of new facility of a Beam Test Stand (BTS) with a structure similar to the beam injection system (ion source, LEBT, RFQ) of the 100 MeV linear accelerator. We plan to actively conduct beam physics and accelerator research using this facility. Moreover, we are supposed to upgrade the proton linac to 1 GeV for spallation neutron source applications, which will be a long-term plan. In short term, we take phased approach with focusing the first phase at 200 MeV energy upgrade.