Miscellaneous （いろいろ） 8 Jul. 2009 Hiroki Kanda

Gas cylinders Cylinders in the 2nd exp. hall 1 almost full cylinders of Ar-C2H6 2 empty and 1 nearly empty (< 0.5 MPa) cylinders of Ar-C2H6 1 nearly empty cylinders of N2 for the operation of the valves of the target controller. Cylinders in Gev-gamma preparation room 2 full cylinders of Ar-C2H6 2 Ar cylinders 2 C2H6 cylinders Several empty cylinders from Tanuma-sanso To Do: Buy a N2 cylinder to be delivered in this week Ask Tanuma-sanso to retrieve empty cylinders Take out empty and nearly empty cylinders in the exp. hall Bring necessary cylinders to the exp. hall Ask Tomoe-shokai and Suzuki-shokan to retrieve empty cylinders

Gas pipelines from outside to the experimental hall Prof. Ishikawa suggested me that LNS can support installing gas pipelines to the 2nd exp. hall from outside, if they have a room in their budget. I would like to send a request to install gas tubes from GeV-gamma preparation room to the 2nd exp. hall. Example of the assignment of the lines to the species of gasses: Ar-C2H6 x 2 lines (for CDC and VDC separately) N2 x 1 (buffer tank of roughly 1 L will be needed in the exp. hall to guard agaist the sudden change of pressure during the operation of valves) H2 x 1 reserved x 2 I think is better to lay the cylinders for Ne and D2 in the exp. hall as the same as so far, because they are small and easily transported by hand. In total 5 – 6 lines are enough for our use.

Air-conditioner The heavy maintenance, almost overhauling, of the air conditioner in the prefab (electronics hut) was done on 8 and 9 Jun. 2009.  It seems its cooling power resurrected, in my feeling. The air duct was set aside for the maintenance.  It was recovered, even upgraded to a more efficient one by Kaneta-san. The windows of the prefab are heavily dewy and the cooled surfaces of the metallic objects even in the prefab are slightly dewy.  I recommend not to set the temperature less than 20 deg. C when we do not use the electronics in the prefab.  The temperature of 20 deg. C is the dew point for the air with the humidity of 55 % and temperature of 30 deg. C.

HV on VDC (superfluous info.) HV of 2.0 kV is applied on VDC today. The STB is operated with the circulating current of roughly 15 milli-amps. The currents of HV power supplies go around several micro-amps (5 – 10 % of the full-scale of 100 micro-amps) during the injection period of STB. By considering the response time of the current meters, the currents may go over 10 micro-amps in a flash.  They trip with 10 micro-amps range. During the circulation period (the radiator is inserted to provide a gamma-beam to GeV-gamma hall), the currents are sufficiently less than 1 micro-amps.