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Institute for Basic Science have been constructing Superconducting LINAC composed of quarter wave resonator (QWR) and half wave resonator (HWR). All QWR cavities have been completely fabricated and successfully tested to be assembled in QWR cryomodules. For now, we have been testing HWR cavities over 50%. For the testing period, the success rate experienced up and downs like we went through during the QWR tests. In many cases, we observed that some cavities did not reach requirement performance 2K although they showed high performance at 4K. We increased the temperature of heat treatment to cure the rapid Q drop at the high gradient and observed most cavities passed the test after heat treatment., Proceedings of the 20th International Conference on RF Superconductivity, SRF2021, East Lansing, MI, USA

All HWRs (half-wave resonator superconducting cavities) have been fabricated and installed in the low energy section of the LINAC in IBS. All HWR cavities have been tested (vertical tests, VT) both at 4.2 K and 2.1 K cryogenic surroundings although operating temperature of HWRs is 2.1 K. Good cavities of high quality factors showed the Q drop tendency of 2.1 k were very similar to that of 4.2 K. However, in many cases, Q drop tendency of 2.1 K were not similar with 4.2 K, rather Q decreased more rapidly than 4.2 K which means the surface resistance of the cavity rapidly increased at 2 K surrounding. In this study, we will report that various Q results of HWRs and compare their Q drop tendency as a function of temperature, 2.1 K and 4.2 K., Proceedings of the 31st International Linear Accelerator Conference, LINAC2022, Liverpool, UK

We propose a tuner control system for low-energy superconducting linac at RAON. The frequency error of the superconducting cavities must be smaller than a few of Hz to operate in beam acceleration mode. To minimize the freuqency error as much as possible, the error is calculated in the low-level RF(LLRF), and the proposed tuner control system changes the superconducting cavity frequency by using a mechanical tuner and a motor attached to the cavity directly. This control system deals with not only the initial frequency error of the cavity but also the frequency drift of the cavity induced by external disturbance such as the slow fluctuation helium pressure automatically. In addition, an automatic proportional gain calibration technique is also proposed. In this paper, the detailed operation and techniques will be described., Proceedings of the 31st International Linear Accelerator Conference, LINAC2022, Liverpool, UK

An ion accelerator, RAON is planned and under construction in Daejeon, Korea by Rare Isotope Science Project (RISP) team in Institute of Basic Science (IBS). The purpose of this accelerator is the generation of rare isotope by ISOL (Isotope Separation On-Line) and IF (In-flight Fragmentation) method. To achieve this goal RAON adopted the superconducting cavities at three different frequency (81.25 MHz, 162.5 MHz and 325 MHz) and their RF field will be controlled independently for the acceleration of ions with various A/q. A solid state power amplifier and a low level RF (LLRF) controller pairs are under development to generate and to control the RF for the cavities. Recently the development and evaluation of the digital-based LLRF have been performed. For the operation and test of SRF cavities, self-excited loop (SEL) and generator-driven-resonator (GDR) algorithm is digitally implemented and its test was performed. In this paper the status and test result of RAON LLRF controller will be described., Proceedings of the 20th International Conference on RF Superconductivity, SRF2021, East Lansing, MI, USA

A prototype of half-wave resonator (HWR) cryomodules is fabricated and tested. Cables and tray are installed for horizontal test. The design and the piping and instrumentation diagram (P&ID) of the HWR cryomodule are presented. The HWR cryomodule is tested with developed programmable logic controller (PLC) and experimental physics and industrial control system (EPICS) control systems. The heat loads of the HWR cryomodule for static and dynamic are measured., Proceedings of the 29\textsuperscript{th} Linear Accelerator Conf., LINAC2018, Beijing, China

Construction of the RAON heavy ion accelerator facility is in-progress in Korea. The driver linac is a superconducting linac with 200 MeV/u for uranium beam and 400 kW beam power. Prototyping of major components and their tests are proceeding including superconducting cavities, superconducting magnets and cryomodules. December 2016, the RFQ accelerated oxygen beam. Status report of the RAON accelerator systems is presented., Proceedings of the 18th Int. Conf. on RF Superconductivity, SRF2017, Lanzhou, China

RAON is a heavy ion accelerator of the Institute for Basic Sciences (IBS) in Korea. The prototype Low-Level Radio Frequency (LLRF) operated at 81.25 MHz has been designed and fabricated for a prototype Radio Fre-quency Quadrupole (RFQ) cavity in RAON. Stabilities of ±1 % in amplitude and ±1 degree in phase are required for specifications of the RFQ system. The prototype LLRF controls the RF amplitude and phase in the cavity by PID feedback loop. The prototype LLRF has been tested with one RFQ cavity and stabilities have been measured. In this paper, we present the design and results of stability test., Proceedings of the 29\textsuperscript{th} Linear Accelerator Conf., LINAC2018, Beijing, China

The recent development of semiconductor technology has proved that solid-state RF amplifier is a quite effective alternative high power RF source for numerous accelerator applications. To develop a high power SSPA system, high power combiner is required to combine the RF power from a lot of solid-state RF module. The parallel plate RF power combiner, which is designed to combine various high power modules, is developed for RAON(Rare the rare isotope accelerator complex for on-line experiment). In this presentation, the status of developed 81.25 MHz 20 kW power combiner will be described., Proceedings of the 18th Int. Conf. on RF Superconductivity, SRF2017, Lanzhou, China

A heavy ion accelerator, RAON is under development in Daejeon, Korea by Rare Isotope Science Project (RISP). In this accelerator, 81.25 MHz Radio Frequency Quadrupole (RFQ) will be used for the acceleration of various ions from several tens of keV/u to about half MeV/u. For this system two 80 kW RF power sources are planned and RISP will develop them with a solid state power amplifier (SSPA) architecture. As a first step, a 20 kW SSPA was developed and its performance was tested. In this presentation the current status of developed SSPA and its test results will be presented, Proceedings of the 18th Int. Conf. on RF Superconductivity, SRF2017, Lanzhou, China

RISP control system uses the EPICS real time distributed control system, which is software framework for stable operation of the accelerator. The output signal from all machines and devices must be archived by EPICS framework, and optimized signal archiver system is needed for each accelerator facility. Signal archiver method using the EPICS framework has three significant ways. First is the classic channel archiver using the file base method and the second is the RDB archiver using the relational database. But classic channel archiver has a problem that the index file containing information of data block corresponding PV data mismatch with real data. Also, there is a problem in the performance of file I/O in RDB archiver. SLAC has developed archiver appliance utility to resolve these problems, and the usage of archiver appliance in EPICS community has gradually increased. RISP choose the archiver appliance to also signal archiver solution. However, archiver appliance is not optimized for our RISP heavy-ion accelerator control system. Thus, we will develop the customized signal archiver system for RISP heavy-ion accelerator control system., Proceedings of the 7th Int. Particle Accelerator Conf., IPAC2016, Busan, Korea

The Rare Isotope Science Project (RISP) Control System is comprised of ethernet-based devices and equipment. Control system is based on Experimental Physics and Industrial Control System (EPICS) Framework, known as a distributed control system through network. So, we need a way for integrating ethernet-based devices into EPICS Framework. Most of these devices support Simple Network Management Protocol (SNMP). SNMP is based on the manager and agent model and it is similar to EPICS Channel Access (CA) protocol. Therefore, SNMP helps to develop a unified network-based control system with EPICS. In this paper, we will show the network device monitoring system RAON customized SNMP integration into EPICS., Proceedings of the 7th Int. Particle Accelerator Conf., IPAC2016, Busan, Korea

The RISP (Rare Isotope Science Project) is developing a superconducting linac which accelerates uranium beams up to 200MeV/u with the beam power of 400kW. The linac consists of an injector which includes an ECR ion source and an RFQ, and superconducting cavities which include QWR (Quarter Wave Resonator), HWR (Half Wave Resonator), and SSR (Single Spoke Resonator). Up to HWR, two charge state beams will be accelerated to achieve the required beam current and then five charge state beams will be used to obtain the higher acceleration efficiency. In this work, we performed the beam optics calculation by using a beam dynamics code DYNAC in order to study a possibility of the code as an online model. We compared the results with the calculation in the baseline design by TRACK code., Proceedings of the 6th Int. Particle Accelerator Conf., IPAC2015, Richmond, VA, USA

The Rare Isotope Science Project at the Institute for Basic Science constructs the rare isotope accelerator (RAON) facility in South Korea. The stable ion beam as an ion source for the RAON accelerator could be generated by ECR ion source system. Therefore, it is mandatory to build ECR ion source control system that could be integrated into an accelerator control system easily. The vacuum control system is an essential part of the ECR control system, because of one vacuum chamber among three different voltage stages (ground, 50 kV, and 80 kV). The preliminary design and implementation of vacuum control system for the ECR ion source will be discussed. It is planned to use a PLC in order to communicate with a vacuum gauge and turbo pump controllers among multi-voltage stages (ground, 50 kV and 80 kV) by optical fibers connection. The PLC system has two major components: a digital I/O module that provides power to each component and standard RS-232 modules which are connected with the gauge & pump controllers. In addition, its extension plan to integrate the vacuum control system into the RAON accelerator control system based on system the EPICS framework, will be discussed., Proceedings of the 15th Int. Conf. on Accelerator and Large Experimental Physics Control Systems, ICALEPCS2015, Melbourne, Australia

The main Low Energy Beam Transport (LEBT) section of Rare isotope Accelerator Of Newness (RAON) heavy ion accelerator is designed to transport the ion beams which are generated by Electron Cyclotron Resonance Ion Source (ECR-IS) to the Radio Frequency Quadrupole (RFQ). In the main LEBT, one or two beams are selected among a variety of ion beams to meet the beamline experiment requirements such as beam charge and current. In a uranium beam case, two charge-state, 33+ and 34+, beams are chosen and transported to the RFQ. For transportation of two charge-state beams, beams can be seriously affected by dipole kick or unexpected dispersion caused by magnet errors. These effects of magnet or cavity errors lead to beam loss at the main LEBT or RFQ. Therefore, the effect to the beam orbit and size should be identified and the research for reducing such effect should be required in the main LEBT. In this paper, we will examine the orbit distortion and beam size growth caused by magnet errors and discuss the correction of errors by using correctors and BPMs., Proceedings of the 6th Int. Particle Accelerator Conf., IPAC2015, Richmond, VA, USA

An ion accelerator, RAON is going to be built in Daejeon, Korea by Rare Isotope Science Project(RISP) team in Institute of Basic Science(IBS). The linac part of RAON consists of two low energy linacs, one high energy linac and two bending section for transporting accelerated low energy ions to high energy linac. It is planned to accelerate many diverse ions like proton, carbon, calcium, uranium, etc. which have different A/q values. Consequently the lattice design for each ion and to investigate beam dynamics issues for each case are one of the important topics for this project. For enhancement of beam acceleration a study to suppress emittance growth and to maximize the longitudinal acceptance is conducted while designing the RAON lattice. In this presentation the designed linac lattices for various ions and start-to-end simulation results will be described., Proceedings of the 6th Int. Particle Accelerator Conf., IPAC2015, Richmond, VA, USA

RAON is a particle accelerator to research the interaction between the nucleus forming a rare isotope as Korean heavy-ion accelerator. RAON accelerator consists of a number of facilities and equipments as a large-scaled experimental device operating under the distributed environment. For synchronization control between these experimental devices, timing system of the RAON uses the VME-based EVG/EVR system. In order to test the high-speed performance of the control logic with the minimized event signal delay, it is planned to establish the step motor controller testbed applying the FPGA chip. The testbed controller will be configured with Zynq 7000 series of Xilinx FPGA chip. Zynq as SoC (System on Chip) is divided into PS (Processing System) with PL (Programmable Logic). PS with the dual-core ARM cpu is performing the high-level control logic at run-time on linux operating system. PL with the low-level FPGA I/O signal interfaces with the step motor controller with the event signal received from timing system. This paper describes the content and performance evaluation obtained from the step motor control through the various synchronized event signal received from the timing system., Proceedings of the 15th Int. Conf. on Accelerator and Large Experimental Physics Control Systems, ICALEPCS2015, Melbourne, Australia

Rare Isotope Science Project (RISP) has been proposed as a multi-purpose accelerator facility for providing beams of exotic rare isotopes of various energies. The RISP driver linac which is used to accelerate the beam, for an example, Uranium ions from 0.5 MeV/u to 200 MeV/u consists of superconducting RF cavities and warm quadrupole magnets for focusing heavy ion beams. Requirement of the linac design is especially high for acceleration of multiple charge beams. In this paper, we present the status of RISP linac design and the development of superconducting cavity and cryomodule., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany

The driver linac of RAON heavy ion accelerator based on the superconducting technology, which consists of a 28 GHz ECR ion source, a low energy beam transport line, a RFQ accelerator, a medium energy beam transport line, a low energy linac(SCL1), a charge stripping section and a high energy linac(SCL2), will produce the stable ion beam from proton with 600 MeV to uranium with 200 MeV/u. Many beam dynamics issues such as beam steering effect due to QWR cavities with the peak electric field of 35 MV/m, emittance growth in charge stripper due to the straggling effect, parametric resonance and envelope instability were verified to design the high power heavy ion machine which can produce the high quality beam. In this presentation, we explain our study results for achieving longitudinal acceptance larger than 27 keV/u-ns for the stable operation and minimizing the emittance growth less than 30 % in the superconducting linac for high quality beam at the in-flight target., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany