Application and Validation of Particle Transport Code PHITS in Design of J-PARC 1 MW Spallation Neutron Source

Abstract

The Japan Spallation Neutron Source (JSNS) is one of the major experimental facilities in the Japan Proton Accelerator Research Complex (J-PARC). JSNS operates with 3 GeV and 1 MW pulsed proton beams, and has the highest-class neutron intensity in the world. In the design stage, aiming for the best neutronic performance, the PHITS code was fully applied in the JSNS neutronics design, and calculations for several thousand cases were performed using complicated models. Not only optimization of neutronic performance, but also shielding calculation, nuclear heat estimation for the engineering design, residual radioactivity estimation for the cask design, and radiation damage estimation for the life and maintenance design were also done with the PHITS code. JSNS is one of the first facilities in the world to fully adapt such a simulation code to the neutronics design. In these calculations, note the change in particle energy from GeV to meV (12 decades), and that neutron fluxes are reduced by 10 decades or more. To confirm their reliability, these calculations were validated by measurement data for neutron spectral intensities, pulse shape, nuclear heat generation, and radioactivity. The results showed that the calculated values were in good agreement with the measured values. We confirmed that the PHITS code was reliable for such design calculations. At the same time, this indicates that the PHITS code is a powerful tool for neutronic design in other radiation source facilities and accelerator facilities.

Energy-Resolved SEU Cross Section From 10-meV to 800-MeV Neutrons by Time-of-Flight Measurement

“…3 shows calculated neutron spectrum intensity at 13.4 m from the moderator surface in BL10 using PHITS code [23] and JENDL-3.2 [21] [24]. This simulation is precisely reproduced the geometry and materials of the beamline around DUTs [25]. The adequacy of the calculated spectrum is confirmed using the foil activation method.…”

Fast neutron tolerance of the perpendicular-anisotropy CoFeB–MgO magnetic tunnel junctions with junction diameters between 46 and 64 nm

“…The fast neutron irradiation experiments were performed at the BL10 (NOBORU) beamline at the Japan Proton Accelerator Research Complex (J-PARC). [18][19][20] The neutron beam was generated by striking a liquid mercury target with a proton beam, using beam power settings of 0.3, 0.4, and 0.5 MW. Low-energy neutrons (with E n below 1 eV) were removed from the beam using boron carbide (B 4 C) slits, while gamma radiation was filtered out with a lead (Pb) block.…”

Targetry overview — Various target concepts and expectable next generation targets in power frontier applications —

“…At the same time, from the viewpoint of the production efficiency of secondary particle beams, the re-absorption should be minimized by using the small target, and the deposited heat density get to be higher. Figure 3 shows the second particle yields for mercury and carbon targets, which were estimated by PHITS (Particle and Heavy Ion Transport code System) calculation with different incident proton energy [4]. In the calculation, pencil proton beam hits a target of 20 cm in diameter and 60 cm in length.…”