[en] The Japan Atomic Energy Research Institute(JAERI) has been proposing the Neutron Science Research Program to explore a broad range of basic research and the nuclear technology including actinide transmutation with use of powerful spallation neutron sources. For this purpose, the JAERI is conducting the research and development of an intense proton linac, the development of targets, as well as the conceptual design study of experimental facilities required for applications of spallation neutrons and secondary particle beams. The Special Task Force for Neutron Science Initiative was established in May 1996 to promote aggressively and systematically the Neutron Science Research Program. The second workshop on neutron science research program was held at the JAERI Tokai Research Establishment on 13 and 14 March 1997 for the purpose of discussing the results obtained since the first workshop in March 1996. The 27 of the presented papers are indexed individually. (J.P.N.)

[en] High Energy Accelerator Research Organization (KEK), which was established on 1 April, consists of two institutes. One of these is Institute of Materials Structure Science. New research program in the new institute using synchrotron radiation, neutrons and muons are discussed. (author)

[en] Development of a proton accelerator based neutron source (1.5 GeV, 5.3 mA (for neutron source 3.3 mA), thermal power 8 MW) is currently conducted by the Special Task Force for Neutron Science Initiative, JAERI. Preliminary design studies and related R and D of a solid metal target for the first stage (1.5 GeV, 1 mA) and a liquid metal target for both the first and second stages (1.5 GeV, 3.3 mA) are conducted by the Target Group to develop both solid and liquid metal target systems. A few kinds of target structures have been investigated in FY 1996 and the preliminary results for the target structures are described in this paper. Investigation results of alternative materials for the target container are also described in this paper. (author)

[en] A research project has been proposed in JAERI aiming at exploring new basic researches and nuclear energy engineering based on a high intensity proton linac with a 1.5 GeV and 8 MW beam. The research complex will be composed of facilities such as the Neutron Scattering Facility for condensed matter physics and the Nuclear Energy Related Facility for engineering test of nuclear waste transmutation. The R and D has been carried out for the components of the low energy part of the accelerator; ion source, RFQ, DTL and RF source. For the high energy portion above 100 MeV, the development on a superconducting accelerating cavity as a major option has been performed. The paper will present the summary on a development plan to build the accelerator and the results of conceptual design study and the R and D work. (author)

[en] 1), As long as a 1.5 GeV-8 MW linear accelerator is constructed in the JAERI neutron science center, it is quite reasonable to construct a 5 MW compressor ring as a driver of a high intensity spallation neutron source to generate pulsed neutron beams. 2), Suppression of beam loss around the compressor ring to an acceptable level is the most crucial subject to be coped with in designing a MW-class compressor ring. This subject should be successfully cleared by carefully studying and designing the overall system of accelerator and tunnel. 3), The 'PSR instability' was comprehensively discussed in the NSNS workshop held at Santa Fe in March, 1997, as a remaining problem of a high intensity proton compressor ring. People of Los Alamos attributed it to an e-p instability. But some questions like the cause that makes some part of protons leak away from a beam bunch to a bunch gap are yet left open. 4), A new scheme of two step H⁰ injection is proposed to remove defects of the conventional one of Los Alamos PSR. (author)

[en] A 200-MeV proton linear accelerator for the Japanese Hadron Project (JHP) has been designed. It consists of a 3-MeV radio-frequency quadrupole linac (RFQ), a 50-MeV drift tube linac (DTL) and a 200-MeV separated-type drift tube linac (SDTL). A frequency of 324 MHz has been chosen for all of the rf structures. A peak current of 30 mA (H^- ions) of 400 μsec pulse duration will be accelerated at a repetition rate of 25 Hz. A future upgrade plan up to 400 MeV is also presented, in which annular-coupled structures (ACS) of 972 MHz are used in an energy range of above 150 or 200 MeV. One of the design features is its high performance for a beam-loss problem during acceleration. It can be achieved by separating the transition point in the transverse motion from that of the longitudinal motion. The transverse transition at a rather low-energy range decreases the effects of space-charge, while the longitudinal transition at a rather high-energy range decreases the effects of nonlinear problems related to acceleration in the ACS. Coupled envelope equations and equipartitioning theory are used for the focusing design. The adoption of the SDTL structure improves both the effective shunt impedance and difficulties in fabricating drift tubes with focusing magnets. An accurate beam-simulation code on a parallel supercomputer was used for confirming any beam-loss problem during acceleration. (author)

[en] The presently available high-energy neutron beam facilities are introduced. Then some interesting research on nuclear reaction using high-energy protons are reported such as the intermediate mass fragments emission and neutron spectrum measurements on various targets. As the important research using high-energy neutron, the (p,n) reactions on Mn, Fe, and Ni, the elastic scattering of neutrons, and the shielding experiments are discussed. (author)

No abstract available

[en] In this report, we introduce the developing plan for a solid metal target structure. Supposing tantalum as the target material, the temperature distribution and the maximum thermal stress in a tantalum plate of a solid metal target was evaluated under a water cooling condition, using the heat generation rate calculated with the JAERI's neutron transport code. The calculation results showed that the water velocity was higher than 10 m/s in order to cool the 3mm-thick target plate down to 200degC when the target surface was smooth and heat transfer rate was calculated with the Dittus-Boelter equation. In this case, the maximum thermal stress is 50 MPa at the target plate surface. The coolant water flow distribution in a target vessel was also evaluated for ISIS-type flow channels and the parallel flow channels. In the ISIS-type flow channels, at least 25mm height of the coolant plenum is needed for a uniform flow distribution. The maximum flow velocity difference between the flow gaps in the parallel flow channels was 30%. A heat transfer augmentation experiment was conducted using ribbed-surface flow channel. The heat transfer rate was confirmed to increase up to twice the value of that for a smooth surface. (author)

[en] An R and D work of a superconducting (SC) cavity for the high intensity proton linac has begun at JAERI in collaboration with KEK. The RF field calculation and the structural analysis have been made to determine the cavity shape in the proton energy range between 100 and 1500 MeV. The results indicate the feasibility of a SC proton linac. A vertical test stand with clean room, water rinsing system, cavity evacuation pumping system, cryostat and data acquisition system has been installed to demonstrate the cavity performance. A single cell cavity of β=0.5 has been fabricated and tested at the test stand to obtain the Q-value and the maximum surface electric field strength. The measured Q-values have been found to be high enough for our requirement while the field strength was limited to about 75% of the specification by the multipacting. We describe the preliminary design of the SC cavity, the overview of the vertical test stand and experimental results of the single cell cavity. (author)