We are developing a new type of photon detector in preparation of an experiment to search for muons decaying into positrons and gamma rays. In the experiment, the photon detector will utilize liquid xenon (Xe) as the scintillation material because of its fast response, large light yield, and high density. The scintillation light emitted in liquid Xe will be observed directly by positioning photomultipliers (PMTs) in the liquid without the use of a transmission window. In order to determine proper experimental procedures and study the detector response to gamma rays, we constructed a prototype utilizing a 100-liter volume of liquid Xe. Current status and future prospects of detector development are reported in this article.
The US-Japan collaboration in the constraction of a BNL muon storage ring for the g-2 experiment (E821) is described from the viewpoint of Japanese collaborators. Japan has contributed in the production of the pole pieces made of a vacuum-melted Ultra-Low Carbon Steel, Al-stabilized Nb/Ti superconductors for the superferric storage ring dipole coils, including technology transfer, and the development of a sophisticated superconducting inflector for muon injection. All of above items seem to be essential techniques to pursue accurate and detailed muon g-2 experiments. Recent experimental results are also mentioned in the latter part of this report.
Multi-strand superconducting cables are utilized for large superconducting machines and/or alternative or pulse current devices, such as fusion machines and superconducting magnetic energy storage (SMES) devices. In the numerical evaluation of AC loss, especially inter-strand coupling loss, it is important to establish a model for crossover contact resistance distribution among strands and/or sub-cables. For cables with multiple cabling stages, the contact resistance between two strands (or two sub-cables) changes along the conductor axis due to the related traces. Good contact is attained at locations whe