• Y.-G. Song, Y.-S. Cho, I.-S. Hong
  KAERI, Daejon

Proton Engineering Frontier Project (PEFP) has above 40 magnet power supplies for the 20MeV proton linac. Because some power supplies have analog interfaces, we chose ATEC (Analog Input To Ethernet Converter) to monitor their output currents and voltage by supporting the protocol conversion function. Software components of the Experimental Physics and Industrial Control System (EPICS) have been ported to a VME single board computer based on a PowerPC microprocessor (MPC7410). This paper presents the software component and processing of analog input values between EPICS on the PowerPC based board and ATEC operating as Server Mode.

• Y.-S. Cho, B. Chung, J.-H. Jang, K. Y. Kim, Y.-H. Kim
  KAERI, Daejon

The Proton Engineering Frontier Project (PEFP) will supply 20-MeV and 100-MeV proton beams from a 100 MeV proton linear accelerator for beam applications. The extracted 20 MeV or 100 MeV proton beams will be simultaneously distributed into the five targets through a dipole magnet equipped with a controllable AC power supply. The most important design criterion is the flexibility of the irradiation conditions in order to meet various user requirements in many application fields. For this purpose, we have designed the beamlines to the targets for wide or focused beams, external or in-vacuum beams, and horizontal or vertical beams. This work includes details of the conceptual design of the beamlines.

• J.-H. Jang, Y.-S. Cho, K. Y. Kim, H.-J. Kwon
  KAERI, Daejon

The 100 MeV Linac of the Proton Engineering Frontier Project (PEFP) consists of an ion source, a low energy beam transport (LEBT), a 3 MeV radio frequency quadrupole (RFQ), and an 100 MeV drift tube linac (DTL). The DTL is separated into two parts. The first part includes 4 tanks which accelerate 20 mA proton beams up to 20 MeV. The medium energy beam transport (MEBT) follows the 20 MeV accelerator in order to match proton beams into the next linac as well as to extract and supply 20 MeV proton beams to the user facilities. The second part of the DTL consists of 7 tanks to accelerate proton beams to 100 MeV. This work focuses on the error analysis of the designed 100 MeV linac in order to obtain the tolerance limit in the fabrication and alignment processes of the linac as well as to study the steering magnets which control the beam fluctuations and reduce the potential beam loss.

• Y.-H. Kim, Y.-S. Cho, J.-H. Jang
  KAERI, Daejon

The PEFP DTL II which accelerates a proton beam from the energy of 20MeV Beam to 100MeV is now under fabrication. The DTL II which has some similar specifications with the DTL I which accelerates the proton beam to the energy of 20MeV is made of seamless carbon steel with Cu electroplating inside. The DTL tank is divided into 3 sections whose length is about 2.2m. We verified the mechanical and thermal stability using ANSYS code, and we established the fabrication process of the drift tube. The DTL II is now being fabricated.

• S. An, Y.-S. Cho, B. H. Choi, C. Gao
  KAERI, Daejon

A new type of coaxial higher-order mode (HOM) coupler with one hook and two stubs has been designed for PEFP SRF cavities to satisfy the HOM damping requirements of the superconducting RF (SRF) linac of the Proton Engineering Frontier Project (PEFP), and to overcome the notch frequency shift and feed-through tip melting issues. This paper has presents details on the PEFP HOM coupler?s structure, structure optimization, filter characteristics, electro-magnetic field distribution and a coupler installation tool.

• S. An, Y.-S. Cho, B. H. Choi, C. Gao
  KAERI, Daejon

An elliptical superconducting RF cavity of 700 MHz with βg=0.42 has been designed for the Linac of Proton Engineering Frontier Project (PEFP). A double-ring stiffening structure is used for a low-beta cavity for a Lorentz force detuning. The results of the electron multipacting analysis of the cavity are presented. A HOM analysis shows that the HOM coupler's Qext is lower than 3·10⁺⁵, thus reducing the influence of dangerous modes on the beam instabilities and the HOM-induced power.

• H. S. Kim, Y.-S. Cho, I.-S. Hong, D. I. Kim, H.-J. Kwon, K. T. Seol, Y.-G. Song
  KAERI, Daejon

The RF amplitude and the phase stability requirements of the LLRF system for the PEFP(Proton Engineering Frontier Project) proton linac are within 1% and 1 degree, respectively. As a prototype of the LLRF, a simple digital PI control system based on commercial FPGA board is designed and tested. The main features are a sampling rate of 40 MHz which is four times higher than the down-converted cavity signal frequency, digital in-phase and quadrature detection, pulsed mode operation with the external trigger, and a simple proportional-integral feedback algorithm implemented in a FPGA. The developed system was tested with 3 MeV RFQ and 20 MeV DTL, and satisfied the stability requirements.

• K. T. Seol, Y.-S. Cho, D. I. Kim, H. S. Kim, H.-J. Kwon
  KAERI, Daejon

The PEFP LLRF system for the 3MeV RFQ and 20MeV DTL has been developed. The stability of ±1% in the amplitude and ±1˚ in the phase is required. Therefore, the drift of the analog components should be low to satisfy the requirement. Analog chassis as a prototype of LLRF system is configured and tested. RF components including an IQ modulator, an RF switch, a mixer, phase comparators, RF splitters, RF filters and trip circuit for high VSWR are installed in this chassis. This performs the shift of RF amplitude and phase from IQ signal, down-conversion to 10MHz IF signal, interlock for arc and high VSWR, and RF/clock distribution. The amplitude and phase stability of each component are measured to check the effect on the whole system performance. The detailed configuration and test results are presented.

• K. R. Kim, W. H. Hwang, H. S. Kim, H.-G. Kim, S. J. Kwon, J. Park, J. C. Yoon
  PAL, Pohang, Kyungbuk
• Y.-S. Cho, H.-J. Kwon
  KAERI, Daejon

The temperature-controlled cooling water system was designed to obtain the resonance frequency stabilization of the normal conducting drift tube linac (DTL) for the PEFP 100 MeV proton accelerator. The primary sizing of individual closed-loop low conductivity cooling water pumping skids for each DTL system was conducted with a simulation of thermo-hydraulic network model. The temperature control schemes incorporating the process dynamic model of heat exchangers were examined to regulate the input water temperatures into the DTL during the steady state operation. The closed water circuits to achieve system performance and stability for low and full duty operation modes were discussed, and numerical results were also presented.

• B. Chung, Y.-S. Cho
  KAERI, Daejon
• Y. Y. Lee
  BNL, Upton, Long Island, New York

The Proton Engineering Frontier Project (PEFP) is a research project to develop a 100 MeV, 20 mA pulsed proton linear accelerator to be used in basic/applied scientific R&D programs and industrial applications. The PEFP proposes the 1.0 GeV synchrotron accelerator as an extension of the PEFP linac, which is a 30 Hz rapid-cycling synchrotron (RCS) with the injection energy of 100 MeV. The target beam power is 87 kW at 1.0GeV in the first stage. The high intensity RCS is one of the important challenges for the spallation neutron source. The conceptual lattice design of the RCS as well as the simulations of an injection system is described in this paper.

• K. Y. Kim, Y.-S. Cho, B. Chung, J.-H. Jang
  KAERI, Daejon

The proton engineering frontier project (PEFP) 100-MeV proton linac has two main beamline systems to extract and deliver the proton beam to the user. The one is designed to extract 20-MeV proton beams at the medium energy transport system of the linac and to deliver them to five target stations through a beam switching system. The other is able to extract 100-MeV proton beams at the end of the linac and to deliver them to another five target stations trough a beam distribution system. We have completed the detailed beam optics designs of the beamline system and performed intensive error analyses to set the marginal limits of engineering errors of the beamline components by using a dedicated beam transport code. The paper presents the error analysis results of the PEFP beamline systems along with their characteristics and beam optics designs.

• K. R. Kim, Y.-S. Cho, I.-S. Hong, H. S. Kim, B.-S. Park, S. P. Yun
  KAERI, Daejon
• H. J. Kim, J. H. So
  Kyungpook National University, Daegu

The test beam line was installed at the MC-50 cyclotron of KIRAMS (Korea Institute of Radiological And Medical Sciences). It has been supporting many pilot and feasibility studies on the development of beam utilization technologies of PEFP (Proton Engineering Frontier Project). The energy measurement with high accuracy is very important for the some experiments such as radiation hardness test of semiconductor devices, nuclear physics, detector test, etc. SSB and Si(Li) detector was used as del-E and E detector and the thickness of detectors are 2mm and 5mm each. The available energy range is 10MeV~39MeV and the flux was controlled not to be exceed 1·10⁺⁰⁵/cm²-sec using a 0.5mm diameter collimator.

• H.-J. Kwon, Y.-S. Cho, I.-S. Hong, J.-H. Jang, D. I. Kim, H. S. Kim, K. T. Seol
  KAERI, Daejon

The beam test of the Proton Engineering Frontier Project (PEFP) 20 MeV proton linear accelerator started again, after the upgrade of the RF control system, One of the important goals of the test is to increase the beam current to the design level. Tuned current transformers were installed along the DTL tanks to measure the beam current itself and possible beam loss along the accelerator. Because there were no empty drift tubes, the current transformers should be installed between DTL tanks. Therefore, the tuning plans were developed to obtain the desired beam properties with the limited number of beam diagnostic devices. Also two BPMs for the time of flight measurement and energy degrader were installed at the end of the 20 MeV accelerator to measure the beam energy. In this paper, the overall test results including beam current and energy measurement are presented.