Aug 4, 2011 SiPM Electrical and Cooling

Tentative Agenda

1. Announcements
2. Action Items
3. Schedule, reporting, and manpower (Elton)
4. SiPM testing (Carl and Yi)
5. Mechanical (Jim)
6. Mechanical drawings (Chuck)
7. Geometry (Elton)
8. Temperature compensation (Jack)
9. Preamp-summing (Fernando)

Minutes

Attending: Jack, Chris, Tim, Yi, Elton, Fernando, Chuck

1. Announcements
2. Action Items
3. Schedule, reporting, and manpower (Elton)
   • Elton noted that several activities are starting to lag, especially the bias circuit testing.
4. SiPM testing (Carl and Yi)
5. Mechanical (Tim)
   • Review what parts should be unaffected by a change in readout granularity and complete those drawings to start fabrication.
6. Mechanical drawings (Chuck)
   • Light guide drawings are being checked. Will be ready for signatures tomorrow morning.
7. Geometry (Elton)
8. Temperature compensation (Jack)
   • Box for temperature tests does not go below about 9 degrees when it is covered. Considering various options of getting it cool for the test
   • Tim offered assistance if needed to complete the project
   • Automatic testing loop sometimes gets communication error and quits. Yi will take a look at it and modify the loop so that the error is cleared and device reset.
9. Elton: Add hardware limits to the voltage settings to protect sensors. This feature should be added to the production boards. Jack will look into adding a zener diode for protection.
10. Preamp-summing (Fernando)
11. Chris: Has laid out the U board with the four decoupling capacitors, but needed to increase the width of the legs by 0.050". Will send Jim the dxf file of U board to check mechanical fit.
12. Low voltage power supply has arrived. Still waiting for bias supply, which should arrive later this month.
13. Chris: The fume hood was being removed out of EEL 126. Jack will check on the status
14. Fernando: Posted GlueX doc on portal with summary of the response of the prototype readout
    • Using 70 ps laser pulse (on loan by Carl), finds rise times ~ 5 ns, and pulse width ~ 60 ns,
    • Checked pulse shape up to 10 MHz, with little degradation. (Note: the pulse height dependence could not be checked because the laser intensity is also rate dependent).
    • Next steps include checking timing resolution, which will be done with the help of Vitaly Baturin (Hall B). The rise time is measured to be about 11 ns.
    • Will keep SiPM test setup in F117 to cross check shape parameters
    • Next step will be to check gain and match the output of the SiPMs from the range of expected photoelectrons to the voltage inputs of the FADC.
15. Granularity
    • Elton briefly discussed the possibility of adding an additional layer to the inside of the Bcal. Studies are ongoing to check the improvement of energy and angle resolution for different options for granularity. Fernando will look into the impact on the electronics layout if an new layer is added.