Weekly JLC Physics Group Meeting

Place: BLDG 3, KEK
Time:  10:30, 97/02/21

[0] Agenda
   0.1) Disk Crash
   0.2) CDC Subgroup Status
[1] Disk Crash (Miyamoto)
   Last Sunday the home directory disk (4GB) for jlcux's crashed.
   The vender of the disk (IAI) says it's difficult to recover
   the stored data. There is a disk rescue company recommended
   by IAI, which inspects the damaged disk for 60K yens and
   then recover the data, if possible, for 400M yens.
   The prospect is, however, not bright because of the software
   striping that has been employed to speed up disk access.
   The last backup as of Dec. 19, '96 has been restored after the
   crash and available now.
[2] CDC Subgroup Status (Yamaguchi)

   Moved the trigger counters back to the central position and
   confirmed that the data taking rate recovered to the previous
   After this, the trigger counters were moved again to the 
   opposite end (signal readout side) of the chamber.
   The 5-wire event rate seemed to drop again on the online
   Tried offline analyses of the data and found the following:

   	i) 5-wire rate is not as different as seen on the online
   	   monitor. This is probably because the threshold is 
   	   higher for the online monitor so that the 5-wire
   	   rate is more sensitive to small difference in the wire

   	ii) the average pulse height is lower at the H.V.-side end 
   	   of the chamber, which happened also to be the gas-outlet-

   	   Suspects are gas gain variations due to

		a) wire sags
			---> probably symmetric about the center
		b) attenuation during signal propagation along wires
			---> correct direction
		c) impurity in gas
			---> correct direction.
	   Probably what is happening is the combination of all the
	   above. Need more studies.