Previous Logbook

11-10-2017

• Wrote a "How too and getting started page" for people to use to do basic dmtpc anaylsis etc it is located here
• Took data sample for purpose of CR-112 calibration, See Adriana's analysis
• Discovered Trigger issues with the DAQ
  • Appears to ignore trigger and pulse polarity settings (at least for the charge sensitive pre-amp)
  • Settings in the hptpc_neutron template (copied from one of the ones that shipped with the setup) has triggers on charge channels effectively disabled.
  • Thus it appears we are triggering only when we have a signal on the fast amplifers, ONLY negative going
  • Need to investigate this, possibility of hard coding or bug in the DAQ initialisation.
• Helped (Tiny bit) with the Ring Turning -> See Zacks page
• Helped (Tiny Tiny bit) with putting clean tent curtains up
• Created a 50ohm terminator for SHV connectors for grounding the anodes
• Grounded All anodes and ground meshes
• Ramped voltage - breakdown reoccurs at same voltages (630-650v)
• Cycled the gas, first pumping down to ~3x10^-6 mbar and then back to 40mbar
• Channels now ramp to 670 without sparking, sparking comes in closer to 680V now
• Cathode performance is identical, sparking occurs at 3200V
• Slowly ramped up all channels to 680V, sparking is moderate, though approximately 0.1Hz so we can get a few events between sparks
• Need to write some error handling into my code, currently segfaults if the first event has no triggers... Thus if the first event is after a spark, it sometimes contains zero triggers.
• Going to migrate to Linappserv and make a set of compiled programs to improve analysis speed
• Have 3 data samples in different configurations for analysis

04-10-2017

• Worked with Adriana on developing the analysis to accept multiple raw files
• Can identify each peak in the spectrum based upon behavour of the CSP channel.
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• All this is within a single run, a spark appears to trigger the change between each state. Looking through later files, the behavour returns to normal and then back to bad again
• Applying peak time cut effectively removes this bad behavour from the files.
• See Adriana's logbook for final plot showing combined files with baseline and time peak time cuts (Also preliminary gain)
• Shakedown of Amplifiers was good, using the test input, scope traces looked identical for all channels.
• 3 instances of bad grounding on the boards which has now been fixed. Extra insulation on the inside of the cases has been added.
• Vessel backfilled with CF4 to 40mbar(30 torr), pressure reached before backfill was 8.44x10^-7 mbar
• Drift field achieved and stable 3200V (compared to 2700V previously) Getting better can at do 100V/cm field at least.
• Anode voltage Bottom left starts to spark at approx 0.5-1Hz when at a voltage of 650V, 50V short of where I usually try and take data to see how everything is behaving.
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27-09-2017

• Baseline Analysis,
  • Initially performed my own baseline extraction in order to learn a few things about the raw TFile structure
  • Rewrote the same analysis in the space of a few hours using the dmtpc framework
• Process is to,
  • Extract the baseline from every trace and push it into a histogram for each channel
  • Fit gaussian/find RMT and define a cut of accepting only waveforms that have a baseline within 8sigma
  • Remove whole events that do not make the cut, Replot and refit.
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• Pulse height analysis
  • dmtpc framework is mostly defined in Pulse.hh (for anyone who is interested)
  • The getPeak() function extracts the peak and subtracts for baseline offset
  • Further acceptance can be performed based on getPeakTime()
  • Code (and a tutorial on what each part of my macro is doing what has been passed down to Adriana for further modification/development (getPeakTime() cuts which shouldn't take much development
  • Currently my analysis works only one a single file though it should be realitively simple to make it work on a string of files.
  • Quite slow... might concider a compiled version rather than a macro, shakes fist at CINT
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• Friday - Adriana and I did a full vacuum system and DMTPC operations tutorial,
  • Made modification to HV feedthrough, changing the connection type to a push on one
  • Applied Kapton insulation over any bare wire, the push on connector and length of the pin.
  • Proved the HV feedthrough operates up to the full capacity of the supply (8kV) in Nitrogen, no sparks or issues
  • Evacuuated vessel
• Started Testing performance of the Cremat boards, Initially tests look like boards are healthy, but we have devised a full set of tests to be performed in order to check board health and operation of different Amps in each
• Should be completed in next couple of days, if all checks are good we move onto the grounding and backfill the detector for sample runs