1. Cryo and AFE IIt Update Fiber Tracker Meeting April 6, 2006 Imperial College A. Bross

2. Cryo Update I  The cryo-system for the VLPCs has been operated extremely reliably and stably from May 05, through the end of the KEK TB and now for about 2 months again at Fermilab  However, it was felt that the thermal-link design could be made more robust u A bolted concept has now been detailed and will be used in all subsequent systems s Modulo one problem u Vacuum tests on the bolt to envelope weld were successful  The drawing package is complete and we have awarded the bid to Ability Engineering for $140k for 4 systems u Does not include s Cryo-coolers s Temperature controlers and sensors s Lid Heater circuitry s Cassette He gas system

3. Cryo Update II

4. Cryo Update III  However II u Need to solve an assembly problem at upper thermal link

5. Cryo Update IV  We recently did a tilt test of the system  Operation at 25 o off normal was fine  We observed an approximately 0.3K temperature increase at stage II (5.2  5.5K)  The Cryo-cooler efficiency is degraded when it is operated off-vertical, but this does not present a problem for the MICE VLPC system

6. Cryo Update V  Excellent temperature stability (spec is  mK)

7. Cryo Update VI  However looking at both cassettes we see that the left-hand cassette is on the edge of being “in control”  Even in the upright position, the LHC will be on the edge with the cryo-cooler compressor operating at 50HZ  REALLY need to solve the thermal link problem

8. AFE IIt Update  The AFE IIt pre-production boards (15) have now all arrived at Fermilab and 5 or 6 are under test  The first boards came up very quickly u In about 1 hour u No green wires!  TriPt testing is done u Yield is about 80% u More than enough chips for D0 + MICE + Spares for both experiments s Plus second pass could yield more  Expect Production Order to be released soon u New issue with discriminator threshold spread u About 10 week lead for delivery of all boards s But many will arrive earlier  The critical issue for MICE is MICE-specific firmware development for AFE IIt u NOT a Trivial amount of work

9. AFE IIt

10. 11/17/2015 LED Spectra: AFE1 AFEII JW@FTG, 2006Mar21

11. 11/17/2015 AFE IIt Discriminators  Turn on spread seen on the platform – much wider than expected

12. 11/17/2015 AFE IIt Discriminators II  More of same

13. 11/17/2015 AFE IIt Discriminators III  Change in AFPGA firmware – now fixed!

14. Issues that still Need some Thought  AFE IIt board temperature and bias calibration u Does MICE need a test stand (like D0 has) to do this operation?  LED pulser data u Plan to dismount wavguides and mount a LED pulser or excite the fibers with blue LEDs?  New LVSB Board u Not likely. Existing board looks OK. 6 new boards are being assembled now. s Firmware development still might be needed –May be able to get support for this from Fermilab CD  Rate u If we keep analog and timing information we are limited to:   250 muons per msec of spill –It is possible that clever (extreme) programming of the AFE IIt can push this up a bit. u If we drop analog and timing and only use discriminators, we can run at 7 MHz.