Status Report of Neutral Kaon photo-production study using Neutral Kaon Spectrometer 2 (NKS2) at LNS-Tohoku(I. Nuclear Physics)

The approach described in this paper uses an array of Field Programmable Gate Array (FPGA) devices to implement a fault tolerant hardware system that can be compared to the running of fault tolerant software on a traditional processor. Fault tolerance is achieved is achieved by using FPGA with on the fly partial programmability feature. Major considerations while mapping to the FPGA includes the size of the area to be mapped and communication issues related to their communication. Area size selection is compared to the page size selection in Operating System Design. Communication issues between modules are compared to the software engineering paradigms dealing with module coupling, fan-in, fan-out and cohesiveness. Finally, the overhead associated with the downloading of the reconfiguration files is discussed

High-power test and thermal characteristics of a new radio-frequency quadrupole cavity for the Japan Proton Accelerator Research Complex linac

We performed a high-power test of a new radio-frequency quadrupole (RFQ II) for the J-PARC linac. RFQ II was developed as a spare RFQ because the operating J-PARC RFQ has suffered from a sparking problem. First, the conditioning of RFQ II was carried out; after 50 h of conditioning, RFQ II became very stable with a nominal power and duty of 330 kW and 3%, respectively. Next the thermal properties were measured because the resonant frequency of RFQ II is tuned by changing the temperature of the cooling water. The frequency response was measured and compared to finite-element method simulation results, confirming that the simple two-dimensional model reproduces the experimental data well. The differences in the field distribution with changes in the rf loading and the cooling-water temperature were also measured, and no serious field distortion was observed. Therefore, we conclude that RFQ II can perform well as a high-power rf cavity

Fabrication and Low-Power Test of Disk-and-Washer Cavity for Muon Acceleration

The muon g-2/EDM experiment is under preparation at Japan Proton Accelerator Research Complex (J-PARC), and the muon linear accelerator for the experiment is being developed. A Disk-and-Washer (DAW) cavity will be used for the medium-velocity part of the accelerator, and muons will be accelerated from v/c=ß=0.3 to 0.7 with the operating frequency of 1.296 GHz. Machining, brazing, and low-power measurements of a prototype cell reflecting the design of the first tank of DAW were performed to identify fabrication problems. Several problems were identified, such as displacement of washers during brazing, and some measures will be taken in the actual tank fabrication. In this paper, the results of the prototype cell fabrication will be reported

Beam test of a new radio frequency quadrupole linac for the Japan Proton Accelerator Research Complex

We performed a beam test of a new radio frequency quadrupole linac (RFQ III) for the beam current upgrade of the Japan Proton Accelerator Research Complex. First, the conditioning of RFQ III was conducted, and after 20 h of conditioning, RFQ III became very stable with a nominal peak power and duty factor of 400 kW and 1.5%, respectively. An off-line beam test was subsequently conducted before installation in the accelerator tunnel. The transmission, transverse emittance, and energy spread of the 50-mA negative hydrogen beam from RFQ III were measured and compared with simulation results. The experiment and simulation results showed good agreement; therefore, we conclude that the performance of RFQ III conforms to its design