April 12, 2011 SiPM Electrical and Cooling

Action Items from previous meetings

1. Determine if swapped bias pins was accidental or in design (Chris)
2. Develop front and back views of jumper sheets. Also get latest version of drawings (Jack)
3. Request Hamamatsu data sheets from Chile to be used as input to jumper settings for boards (Elton)
4. Double-check that the jumper settings for #37 (U-board counting) are correct (Jack)
5. Provide section views of board to Fernando (Jim)
6. Run temperature configuration for cooling plate with new geometry (Jim)
7. When design is complete, order 2 mechanical assemblies with latest geometry (Jim) In progress as design is finalized
8. Populate SiPM wedge board to be used for checking electrical issues (Fernando and Chris)

Tentative Agenda

1. Announcements
2. Action Items
3. Schedule, reporting, and manpower (Elton)
4. SiPM production testing (everyone)
5. Mechanical assembly (Scot)
6. Mechanical (Jim)
7. Mechanical drawings (Chuck)
8. Temperature compensation (Jack)
9. Preamp-summing (Chris)

Minutes

Attending: Fernando, Eugene, Elton, Jim, Nick, Andrei, Tim, Jack

1. Announcements
2. Action Items
3. Schedule, reporting, and manpower (Elton)
4. SiPM production testing (everyone)
   • Software updated to latest changes
   • Cable for temperature sensor (borrowed for mini-Bcal) has been replaced
   • Chiller is being refilled with liquid
   • Bobby, Tom and Elton will meet with Yi to learn how to operate the system
5. Mechanical assembly (Scot)
6. Mechanical (Jim)
   • Showed latest thermal FEA calculations
   • Model has ss standoffs and plastic washer to isolate the cooling plate from the spreader board
   • The connections to the 4-wire RTD needs to be finalized including connections through the top plate. Could possibly use the connector used for power
   • Currently the model shows a variation of 0.8 deg C across the cooling plate. Changing the standoffs to plastic reduces the gradient from 0.8 to o.6 deg C.
   • Two watts of heat is conducted from the spreader plate down to the cooling plate
   • The cooling plate dissipates 12 W, 10 W is convective heat load
   • Maximum temperature on the spreader plate is about 50 deg C.
   • It will be useful to study the temperature gradients on the mini-Bcal readout after removing from Hall B.
7. Mechanical drawings (Chuck)
8. Temperature compensation (Jack)
   • Difficulty finding higher precision resistors.
   • Final optimization will occur once the operating point is determined for the SiPMs (from beamtest)
   • Fernando: may also wish to revisit the standing current in the chain
9. Preamp-summing (Fernando)
   • Ringing on boards has been found (first in the EEL and also in the beam test data)
   • Did not previously look for it on the bench
   • Third wedge is almost assembled and will be used to diagnose the ringing problem.
   • Data from the beam test with one bias on at a time is being studied for clues to the problem.
   • PS is now under new software control in F117