Minutes of the forward endcap EMC eZuce SRN meeting, 25th of September 2017, 14:00-15:00

Presence:

• Basel: Werner
• Bochum: Cathrina, Claudius, Fritz-Herbert, Malte, Matthias, Miriam, Tobias T., Tom
• Bonn: Christoph, Merlin
• Groningen: Myroslav
• Stockholm: -
• Uppsala: Pawel
• Giessen: Hans-Georg, Markus
• GSI: -

Preamplifiers:

• The gain of all VPTT preamps is now measured in Bochum, there is much more spread in the gain distribution (+20/-10%) than the Basel measurements imply
• Gain variation clearly tracked down to gain-determining capacitor in feedback-loop: Changing this capacitor changes the preamp gain accordingly
• Two extreme behaving preamps (high/low deviating gain) have been sent to Basel for remeasureing
• Besides the high relative gain variation, we cannot confirm the absolute gain values, which come out much higher than expected (preamp output signal amplitude as response to 1pC charge input (1 V-rectangular signal via 1pF capacitor)
• The preamp gain data measured in Bochum will be given to Merlin for work on the reassignment of components for the VPTT submodule build

SADC crates:

• The SADC crate cooling would need a final measurement with higher precision temperature and flow sensors to confirm usability of the system (pressure drop, flow)

DAQ tests:

• The KVI 3x3 crystal EMC protoype has been revitalized with modified Basel preamps
• Cosmics measurements with this setup came out fine
• Readout/data flow chain is: SADC board -> data concentrator -> compute node
• Work on software, storing of data, and online data processing ongoing
• Easy to use control software under construction that is called by EPICS and makes all necessary settings
• November/December the prototype will go to Cracow for combined cosmics runs with the STT prototype (and additionally a beam time at COSY in spring) and clustering tests over different ADC boards (4 boards to be connected to the 9 crystals)
• Christoph added that an electron beam up to 3 GeV in a dedicated test area at ELSA would "easy" to realize, MAMI may be an additional alternative