Quick VPT Test Rig meeting - minutes

Date of meeting: 7 December 2001

Venue: RAL

Present: B Kennedy, N van der Kolk, L Lintern, P Flower

1. Report from Brunel: NvdK reported on recent work at Brunel. 
   • Still trying to reduce noise in irradiation rig electronics.   See ~5k e- with no VPT present, and unexplained fluctuations in noise.
   • Five MELZ VPTs have been tested at 0T and 4T.  They give typically 60% of the response of RIE VPTs - similar gain, but lower photocathode sensitivity.
   • A VPT has been left in the 4T field for 5 days - this had no effect on the performance of the device.
2. Hardware: ALL has mounted row 3 in the rig - it rotates freely in the bearings. The lids for this row, incorporating screening mesh, should be finished early next week.

3. Data-taking: MS has repeated the SPS-mode data-taking.  As before (Sep 2001) the short runs (50 events/run) show a higher pulse size than the long (100-event) runs, with the effect typically being 2-5%.   The photodiode channel shows no variation in pulse, indicating that the LED output is constant.  It therefore seems that this effect arises in the VPTs.

4. Software: BWK has sent the electronic passport spreadsheet to RIE.

5. Delivery of VPTs: Hans Rykaszewski has passed on a message from RIE: the first batch of 100 VPTs left RIE yesterday bound for Customs.

6. PPARC visit, Jan 9: BWK has asked Justin G, Brian S and Tony L to supply items for the ECAL display.

   • A large drawing of the ECAL endcap

   • Photographs of the mechanical tests carried out on the supercrystals

   • The components of a complete supercrystal, including 25 crystals.

   The test-rig area will require considerable tidying before the visit.

Bruce Kennedy / 05 December 2003