Quick VPT Test Rig meeting - minutes

Date of meeting: 14 July 2000

Venue: RAL

Present: B Kennedy, L Lintern, M Sproston, A Turner, J Williams

1.  Mechanics

• ALL working on relay box - awaiting some components.  Next week taken up with leave/courses, so box should be ready for week of 24 July.
• JHW reported that the eight VPT boxes in a glued row are in electrical contact with each other - end-to-end resistance of row is less than 1 Ohm.   It remains to be seen whether this is will be good or bad for the noise performance of the whole array.

2. Electronics

• Preamps - information from Dave Cussans in response to email from BWK.  Motherboards + one 5-channel card are in Bristol wiating for connectors.   The other 50-channel card is at CERN, and one channel needs repair.  Should be available soon.  BWK will chase DC again.

3.  Single-channel  tests

• MS/JHW achieving noise of  ~2800e - expect ~1100.   Possible that stepper motor may be contributing to this.  ALL has arealy system to cut the mains power to the stepper motor during measurement.  [Note added later: DJAC points out that MS is using 1m cables rather than the 50cm used at CERN => expect 2* noise from extra capacitance.  If this is correct, the figure of 2800 looks good.  MS/JHW will replace cables and retest.]
• LabView control/daq program working even without CAXP at the controls.

4.  Database

• BWK has given specification of data structure to J-M LeGoff for coding into CRISTAL.
• Agreed that we need to have an independent system for data management to allow analysis and control of measurement procedures without extra complication of CRISTAL.  A possible option is to use LabView to control all measurements, then use flat files or a simple database application (in eg Filemaker Pro) for data storage.  Then use CRISTAL just as a repository for data.
• Two bar-code readers received from RS.  Ordered wrong interface cables my mistake - replacements should arrive soon.
•  

Bruce Kennedy / 05 December 2003