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Participants:
Alex, Andrew, Christian, Giuliana, Ben Smith, Claudio S, Claudio G, Davide, Luigi R, Paolo, Tom, Sosuke, Yi, Manuel Rolo, Daria, Hanguo, Marco R, Pierre, Sam, Valerio, Edgar, Simone, Masayuki, Christian, Emilija, Francesca, Graham, Luigi P
Proto-0 TPC run with mechanical mock-up:
The operation concluded on Oct.16 at 16:00, after 6 full days run. The system is currently warming up (at the time of the meeting the liquid level just dropped below the mechanical mock-up MB with wire bondings).
One wire bonding broke during the pre-cooling operation. The exact cause is unknown, visual inspection with a microscope can reveal some details.
For the future, operations will be more careful: start pumping with slowly opening the valve, wait until the temperature in the vessel stabilizes by radiative cooling (argon only in the outer bath, inner detector under vacuum), inject gas in very small amounts.
Keithley DAQ6510 is being prepared to accept remote commands by Pierre, which will allow continuous monitoring and data logging in the future.
Next run with MB2:
The current schedule is: next week open the cryostat, disassemble the TPC, review the installation procedure with the mock-up, start MB2 installation on Oct.27, close the vessel, prepare the run to start on the week of the collaboration meeting in Naples.
We need to monitor the PDMs (wire bondings) when cooling the MB2. This can be done via the steering module and CAEN A1540 board, by monitoring the current flowing through the SiPMs.
Photoelectronics cannot be switched on in vacuum, and neither in low pressure gas, as FEBs require minimum of 100 mbar around them in order to dissipate heat. In addition, the video camera and LED strips will be on during the filling stage.
Hence, the sequence of operations should be as follows: pump vacuum, inject gas, slowly fill until reaching ~1 bar, turn on FEBs (few seconds), take IV curves.
Ideally we need 30 points for IV (full scan will take about an hour), but initial diagnosis might be done with less. One point is definitely not enough when the temperature is changing. In the operation stage, the IVs are to be monitored daily, or after any change in operational parameters.
IVs start at 45V and go up to 60V, as the voltage switch from Brookhaven does not allow to work below 45V.
While at room temperature the IV curves can be taken in the dark, below 100K we will need a light source.
Pierre already has the script to read out voltage and current from the power supply module.
Detailed instructions (flow diagram), together with the required software, will be provided by Alessandro/George/Brookhaven.
Electronics for the next run:
The full list of required equipment is at the following link:
https://docs.google.com/spreadsheets/d/1D4r-0n9YhGc_MVg-xY-wZblBje84ohFuyBf-cfqWp-Y/edit#gid=0
PE group will bring Keithley power supply for the MB2 installation and checks in the clean room (then take it back).
For CAEN boards, SY5527 has been rented from CERN E-pool (price ~100chf/month). An A1520P board was also rented for the DAQ WG to work on the communication (1chf/month).
A2517 board is being modified at CAEN (DB37 connector), and will be brought to Yi.
A1540 board will be brought by Yury (Oct.27 or later). Alex will be in touch for reminder.
UPS has been shipped from TRIUMF to CERN (lab 182, Alex as recipient).