TOKAI-MURA, IBARAKI - The secondary beams checkout has been started at Hadron Experimental Hall in Nuclear and Particle Physics Facility of J-PARC.
Following the successful acceleration of proton beams by the 50 GeV Synchrotron on January 27, the secondary particles produced when the extracted protons hit a nickel metal disk target in the Hadron Experimental Hall. Pions, kaons and protons are successfully transported to a beam line called K1.8BR (
Figure 1) for the beam quality check on February 11.
Two experimental groups E17, lead by Professor Ryugo Hayano, University of Tokyo and E15, lead by Dr. Masahiko Iwasaki, Riken, have joined the operation of the beam line with the J-PARC construction team. The beam line magnets were adjusted so that the beam momentum is held at 1.1 GeV/c, and the team obtained the signal of pions and secondary protons and their time-of-flight counter (
Figure 2).
On February 16, the team also successfully operated the Electro-Static Separator (ESS) in the working beam condition. This apparatus increases the density of kaons in the secondary beams.
The operation of the 50 GeV Synchrotron for the fiscal year 2008 was terminated on February 26. KEK will continue constructing and tuning the other beam lines such as K1.8 and KL. At K1.8BR, full installation of the E17 experiment will resume, preparing for the next operation phase which will start in this autumn at the earliest.
J-PARC has been under construction since 2001 jointly by Japan Atomic Energy Agency (JAEA) and High Energy Accelerator Research Organization (KEK) at Tokai village in Ibaraki prefecture, Japan. The accelerator complex consists of three stages, the LINAC, 3 GeV Synchrotron and 50 GeV Synchrotron.
