Annual Report 2015

I am glad to report the various progresses in 2015 at RCNP in this online annual report. As an introduction of the report, I give you a short summary of the high activities.

At the EN course of the Cyclotron Facility, experimental campaign of in-beam gamma-ray spectroscopy using CAGRA (Clover Array Gamma-ray spectrometer at RCNP/RIBF for Advanced research) was carried out using stable and unstable heavy ion beams to investigate structure of ¹⁵B, ³²Si, ⁴⁴Ti, ⁶¹,⁶²Fe, ¹⁴²Pr and ¹⁸⁶Re nuclei. At the Grand Raiden Spectrometer,proton inelastic scattering experiments on sd-shell nuclei have been performed, which demonstrates that the isoscalar spin-M1 mode exhausts most of the sum-rule strength. This fact is in contrast with the case for the iso-vector strength of Gamow Teller mode suggesting a finite spin expectation value due to tensor correlation between protons and neutrons.

The first user experiment of the MuSIC muon beam line, E411, was performed successfully, after beam commissioning and measurements of the beam line. For material science experiments, a µSR spectrometer has been installed at the end of the beamline, and spin polarizations of the muon beam were measured using the spectrometer. MuSIC plans to start full beam intensity operations from 2016.

In the Laser-Electron Photon facility at SPring-8, both LEPS and LEPS2 beamlines have been operated in the stable condition. The maximum beam energy was extended from 2.4 GeV to 2.9 GeV by using 266-nm deep-UV lasers at LEPS, and processes of meson photoproduction like phi and K* in higher energies have been investigated. At LEPS2, the experiment of the search for eta-prime mesic nuclei has been continued with BGOegg to increase statistics.

Hadron Physics has been also persuaded at J-PARC. A High-p Collaboration has been formed toward a new joint research platform on hadron physics at the J-PARC high-momentum beam line. Collaborative works to develop detectors and high-speed data acquisition system have started. Experimental feasibility to study Λ(1405) via the d(K⁻,n) reaction has been demonstrated at the J-PARC K1.8BR beam line.

As for the application of the accelerator and radio-isotopes, a new project for realizing targeted RI therapy using alpha particles emitted from ²¹¹At was started under the framework of cooperation among RCNP, Graduate Schools of Medicine and Science in Osaka University to enhance the five-year relative survival rate for advanced cancer treatment. A 29 MeV ⁴He2⁺ ion beam was regularly provided for At-211 production using the nuclear reaction of ²⁰⁹Bi( ⁴He, 2n ) ²¹¹At at the AVF cyclotron facility.

The RCNP reaction theory group started to be involved in the ImPACT program for "Reduction and Resource Recycling of High-level Radioactive Wastes through Nuclear Transmutation." They were developing a microscopic effective reaction theory (MERT) to predict reaction data that are important for the transmutation study but cannot directly be measured. As a first step, they have theoretically generated deuteron reaction cross section "data" for various target nuclei including long-lived fission products.

As an activity of physics using the supercomputer, there was a progress in the lattice QCD calculations for the study of the QCD vacuum. These calculations indicate the strong relation between chiral symmetry breaking, instantons and monopoles, which are essential for the understanding of the QCD vacuum.

You will find the details of these highlights in the annual report. I hope you will find them interesting. Please enjoy!

Sincerely yours,

Takashi Nakano
Director of Research Center for Nuclear Physics