Quick VPT Test Rig meeting -
minutes
Date of meeting: 12 May 2000
Present: PSF, BWK, ALL, CAXP, MS, JHW
1. Mechanics
- All components now in hand
- Assembly started; first bank of 8 VPT holders should be ready for
testing with stepper motor under LabVIEW control by 19 May.
2. LabVIEW
- Stepper motor control system is ready for tests next week.
- Can now control HV supply; cosmetic improvements (nice control panel
etc) in next few days.
- Magnet control application exists; cannot test until magnet cooling
water becomes available (about 2 weeks).
3. HT
- ALL has started to build the leakage current box.
4. Electronics, LEDs
- BWK received an email from David Cussans concerning Stephenson
preamps. Bristol are having a set of 5-channel boards made for the testbeam.
We will request a spare board for testing (available by 19 May), and a 6*5 channel
system should be available in the first week in June. Bristol will find a suitable
box for the system; our only special requirement is that it should be non-magnetic.
- Preproduction VPTs will arrive from manufacturer with 10 hours
burn-in. Results obtained by MS indicate that a longer burn-in period is required to
reach a steady operating state, so we must still make provision to burn-in the VPTs.
The lids for the VPT holders are already drilled with 4 holes. [Note added
later: the VPT specification agreed with the manufacturer relates only to the loss in
output after 10 hours burn-in. ]
- Would be beneficial to use ultra-bright LEDs for pulsing, to avoid
noise from the 60V avalanche pulse generator. These LEDs are 5mm in diameter rather
than 3mm, but should be usable. A possible disadvantage is that their output peaks
at 470nm rather than 430nm like the lower output (hyperbright) LEDs - some investigation
is needed to check whether this has any significant effect.
5. CRISTAL
- ALL purchased a 500MHz PC for the supercrystal testing programme.
It appears that this PC will be spare, so could be used as the CRISTAL db server.
Will need a memory upgrade from 128Mb to 512 Mb (about £200).
- CRISTAL experts recommend RAID disks for reliability. Probably
not necessary for VPT tests, as time lost to a hard disk failure would not be critical.
Need to consider needs of SC Regional Centre as well, where periods of down time
would be more serious and a RAID array might be justified.
- A suitable location must be found for the CRISTAL server.
Bruce Kennedy /
05 December 2003