Abstract Ceramic breaks are used in synchrotrons for many purposes. For example, they are inserted between the Multi-Wire Profile Monitor (MWPM) on the injection line at the Rapid Cycling Synchrotron (RCS) in J-PARC to completely prevent the wall currents accompanying beams from affecting the MWPM. On the other hand, from the viewpoint of suppressing beam impedances and the radiation fields from the ceramic breaks, it would be preferable that the inner surface of the ceramic break is coated with Titanium Nitride (TiN), or covered over capacitors. In this report, we measure the radiation fields from the ceramic break with and without capacitors as well as the beam profile and investigate the effect of the ceramic breaks on the measurements.
In this paper, we propose a new control method which realizes “well-organized” crossing motion of multiple swarms of robots. Although there are several researches which realize crossing motion of multiple swarms of robots without collision, the transient state is not considered. To realize “well-organized” crossing motion, we define what “well-organized” crossing is in this study, and then propose the crossing motion planning method which consists of an offline path planning, an online follow-up control and online collision avoidance. Especially, in the offline path planning, which is based on model predictive control, a trajectory without disorder of the formation is generated. Furthermore we show the validity of the proposed mothod by some simulations and experimental results.
A 3 GeV rapid cycling synchrotron (RCS) at J-PARC was commissioned in October 2007.Afterwards, the beam intensity was increased through a beam study, and the RCS has continuously provided a proton beam >100 kW to the neutron target since October 2009.With renewed efforts brought about by beam commissioning, we have reduced losses in the RCS and achieved low-loss operation.We present the history of the operational beam power and the residual dose distributions after operation.
The 150MeV FFAG is a prototype FFAG synchrotron for practical applications. The fast extraction of proton beam from a FFAG ring is the first trial in the world, and the demonstration is a milestone for a practical FFAG accelerator. In the paper, the overview of the beam injection and extraction schemes in the 150MeV FFAG is to be presented
In the Japan Proton Accelerator Research Complex (JPARC) 3-GeV rapid cycle synchrotron (RCS), transverse beam halo scraping for the injection beam is required to increase the output beam power. The transverse scraper system at the Linac-RCS beam transport line (L3BT) was utilized in a nominal beam operation because the area of the scraper section was contaminated when the scrapers were working. In the summer-autumn period of 2013, we installed the new beam-halo scrapers which had optimized scraper heads for mitigation of the radiation around the scraper system. In this paper, we report a preliminary result for a halo scraper at the L3BT.
The DsTau project proposes to study tau-neutrino production in high-energy proton interactions. The outcome of this experiment are prerequisite for measuring the $\nu_\tau$ charged-current cross section that has never been well measured. Precisely measuring the cross section would enable testing of lepton universality in $\nu_\tau$ scattering and it also has practical implications for neutrino oscillation experiments and high-energy astrophysical $\nu_\tau$ observations. $D_s$ mesons, the source of tau neutrinos, following high-energy proton interactions will be studied by a novel approach to detect the double-kink topology of the decays $D_s \rightarrow \tau\nu_\tau$ and $\tau\rightarrow\nu_\tau X$. Directly measuring $D_s\rightarrow \tau$ decays will provide an inclusive measurement of the $D_s$ production rate and decay branching ratio to $\tau$. The momentum reconstruction of $D_s$ will be performed by combining topological variables. This project aims to detect 1,000 $D_s \rightarrow \tau$ decays in $2.3 \times 10^8$ proton interactions in tungsten target to study the differential production cross section of $D_s$ mesons. To achieve this, state-of-the-art emulsion detectors with a nanometric-precision readout will be used. The data generated by this project will enable the $\nu_\tau$ cross section from DONUT to be re-evaluated, and this should significantly reduce the total systematic uncertainty. Furthermore, these results will provide essential data for future $\nu_\tau$ experiments such as the $\nu_\tau$ program in the SHiP project at CERN. In addition, the analysis of $2.3 \times 10^8$ proton interactions, combined with the expected high yield of $10^5$ charmed decays as by-products, will enable the extraction of additional physical quantities.
