Plastic Scintillator Meeting Agendas

• https://zzz.physics.umn.edu/cdms/doku.php?id=cdms:montecarlo:ebook:al_refl:
• Further work this (or upcoming) semester?

• Jake is re-doing the aluminum reflectivity study with Ryan's files
• Decide to re-do Gd(iPr)3
  • 0.2 cold bath
  • 0.2 hot bath
  • 0.5 cold bath
• Pictures will show up in the table under June 14

• Discussion of photocathode reflectivity

• Measurement of Eta
• Errors for Gaussian fits
• Extend active period for David-Michael's email address (degui008@umn.edu)

• Educational activities for Jake underway (and almost finished)
• Simulation matching; how to proceed?
• Replace XY plot with radial plot?

• Monochromator runs
• New scintillator samples
• Next steps for paper?
• New Experimental Overlays (PE at 1cm)
• Old Experimental Overlays (PE at 9 cm)
• PE Contour at 1 cm
• PE Contour at 9 cm

Quantum efficiency adjusted values and plots for paper

• Muon Spectrum results and WLS trapping photon comparison

• Does particle scattering inside scintillator lead to increased light output?
  • Short answer: No, it doesn't
• Updated computational section

• Updated attenuation length runs
• Stuff for paper
• Reminders:
  • DMP thesis talk: Monday 4/30 @ 4:40pm in TATE 301-20
  • RS thesis talk: Thursday 5/3 @ 10:10am in PAN 110

• "Attentuation length" measurement and comparison, page 3, updated
  • Jake was able to collect data for the 0.96 reflectivity measurements, the data is updated in the table on this page
• Picture ideas for paper [updated]

• Updated attenuation length runs
• PDE measurement summary

• "Attentuation length" measurement and comparison, page 3, updated
• Picture ideas for paper (v1)

• Background run with the new configuration

• "Attentuation length" measurement and comparison, page 3

• Updated attenuation length runs
• Background run with the new configuration

• Going to have Jake collect some data; what data do we want to make more robust? (Effective Attenuation Lengths?)
• Muon triggering system implemented, see demonstration (is this a valid approach?)
• Added super-long attenuation length (100m) to data from previous meeting's presentation

• "Attentuation length" measurement and comparison, page 2

• Updated NaI runs
• Potential collaboration with DarkSide
• Paper meeting on 3/26 @ 1:30pm
  • Ryan:
    • Thank you for sending paper section
    • I also need for paper:
      • Cf-252 initial neutron energy spectrum, text file
      • Gamma spectrum that results from neutron capture on Gd, text file
        • Visualization/description of how this was obtained is on this page
        • Version of the spectrum with 100 bins
        • Version of the spectrum with 1000 bins
      • Version of Geant4 which you are using
        • Geant4 10.02

• "Attentuation length" measurement and comparison

• NaI runs

• Reflectivity/WLS Efficiency Study, more robust data

• Reflectivity/WLS Efficiency Study, updated optical approach
• General Statements:
  • 1 mm air gap is detrimental; a small air gap is best
  • Painting back surface of scint to decrease reflections doesn't remove the shoulder of the distribution
  • Decreasing att. length just performs an overall reduction of PE counts

• NaI detector shielding
• “Feb 29, 2018” -DMP, 2/28/2018

• Reflectivity/WLS Efficiency Study, updated optical approach

• NaI detector shielding
• Monochrometer Measurements

• Optical Simulation Nuances in Geant4
• Overview: A collection of tiny details were altered to make the simulation more accurate. Net effect: no overall change to what we saw before, in mean, but changes in detected wavelength and peak shape

• Neutron capture efficiencies

• Reflectivity/WLS Efficiency Study (don't click; this data is unusable)

https://zzz.physics.umn.edu/cdms/doku.php?id=cdms:plasticscintillator:ebook:monochromatorprocedure

• 511 keV peak in small scintillator samples

Figure 1:	Figure 2:

• NaI detectors: Cf-252 runs
  • Large lead/poly shielding around source, nothing between source and Gd target
  • Not sure why source only run has a higher rate at low energies

Figure 3:	Figure 4:

Figure 5:

• Muon runs for attenuation length
  • Commercial scintillator has attenuation length of 150cm for 1x20x200cm slab of BC-400 (the slabs we have)

Figure 6:

• Paper discussion
• Na-22 analysis
  • New energy deposition sim needed
• WLS fiber trapping efficiency
• NaI detectors

• Reflectivity/WLS Efficiency Study

• Neutron capture results

• WLS Trapping Efficiency comparison (light loss)

• Capture measurements using thermal neutron background
  • Upper bound of capture rate: 700 captures/hour
  • Coincidence between Detectors B and C (0.4 MeV thresholds)
  • Detectors summed, weighted by run time, neutron flux
  • Background run subtracted from run with Gd
    • Background rate = ~1 Hz
  • Observed 1±10 counts/hour more between 0 and 8.5 MeV when Gd present
    • Limits of coincidence, gamma angles
• Will be using PuBe source for next set of runs

• NaI pulse shape analysis
• Cf-252 runs with NaI detector

• Cf-252 runs with NaI detector

• NaI detector characterization
• DMR-15 attenuation length
• Paper draft will be locked starting Monday for edits
• Ignore below
  • SiPM response function
  • SiPM discussion
    • | Quote from CAEN
    • CMS SiPMs
    • Other options?

• Finished filling out paper figures list (with some minor questions still needing to be resolved)
  • Reference to Paper Figures

• Cf-252 runs
• Updated LCAE attenuation length analysis
• Paper discussion
  • Which samples do we want to discuss?
  • Include fiber trapping efficiency?
  • Author list
• SiPM issues
• TB4 board

• Energy of gammas entering scintillator (and a PE count set)
• Muon Energy Deposition in Scintillator
• See next week for paper figures list

• LCAE-01,04 attenuation length

• See Nov 9 meeting for updated Energy plots (added inspection of thermal neutron generation rate)

• Introduction and comments
• V4 -- Computational Contributions (Writeup I wrote before/during summer)

• LCAE sample attenuation length
• Sample mailed to SNOLAB for radiopurity measurement, should start counting Monday
• CAEN update – Hannah
• TB4 update
  • Waiting on response from Paul
  • Documentation says max trigger rate is ~10Hz
• Paper update
• Tanmay research project?

• Comparison plots: Cf252 Neutrons, Gammas, N+Bucket, N+Bucket+Gd

• See next week for updated results

• CAEN update
  • Need pre-amp for experimental setup
  • Will email Paul about TB4 board
• PDE measurements

• LCAE sample characterization
  • Rescale to photoelectrons?

• Updated old agenda details with pages and details
• Gamma Spectrum -- 1 keV neutron capture on Gd
  • Seems to indicate that high energy gammas were being produced by some process involving neutron capture with high energy neutrons

• Cf252 Neutron Spectrum (using this moving forward)
• New PE Count results with updated Cf252 spectrum (not much different from old spectrum)
• Possible other physics lists to use:
  • HP Neutron Capture Model G4HadronPhysicsShielding class reference
  • Conclusion: We are probably already using the data that these high precision neutron capture classes use, so there should be no problem
• Terminal Output of Gd Capture Events with total gamma energy>8.5 MeV

• PMT quantum efficiency measurement
• SiPM gain measurements
• SiPM PDE measurements
• Future plans:
  • ????
  • Cf-252 runs with Gd vial, poly
  • LCAE sample characterization
  • Paper
• Tanmay
  • Started training with basic experimental procedures
  • Safety training needs to be done (physics account??)
  • Install Root

• Gamma Spectrum Parameterization
• Possible spectra to consider when making our own Cf252 spectrum to use:
  • Cf-252 Low Energy Neutron Spectrum Paper
  • Cf252 Mid Energy Neutron Spectrum Paper
  • Cf252 High Energy Neutron Spectrum Paper
• Gamma Energy Spectrum due to capture: On H, On Gd

• PMT gain measurements
• PMT quantum efficiency measurement
• Cf-252 runs, update from previous discussion

• Cf-252 Energy Spectrum (wrong)
• Cf-252 Gamma Energy Spectrum (see 9/21 meeting above for parameterization that was shown)
• Gamma Energy Spectrum due to neutron capture on Gd, H (see page under 9/21 agenda for details)

• SiPMs:
  • Can't measure photocurrent directly. Current (~0.2 milliamps) is too large for Keithley 237 ammeter but current fluctuations are too small for microammeter to measure. This method also injects a lot of noise into the SiPM circuit so I wasn't able to see individual photoelectrons.
  • Tried a new method to measure SiPM PDE
    • Results are still being analyzed
• PMT:
  • Wrote LabVIEW program that histograms pulse amplitude as well as area in real time.
  • Began by self-triggering to get 1st photoelectron peak, but had trouble getting second photoelectron peak with light leaks.
    • 1st PE at about 16mV
  • Tried triggering on LED flashed using pulse generator to get individual photons
    • Do we have any pulse generators with faster rise times (<5nsec)?
    • Will measure single PE amplitude and area as a function of PMT bias this coming week.

• I had to move out of my apartment this past weekend so I will be out of town from tomorrow through Labor Day.
• I will be catching up on documentation and writing more of the paper.

• PE Counts in Gamma Catcher, Cf252 Neutrons with Trigger
• Eclipse vacation for past week took up time; will need to do commenting/editing run of paper in next few days before band starts on Thursday

• Finished TB4 board and SiPM characterization measurements
• Subsequently, the calculation of SiPM gains could be done
• PMT, SiPM quantum efficiency measurements
  • Measured anode responsivity of PMT successfully
  • Issues:
    • SiPM doesn't give good results
    • No known gain for PMT so anode responsivity cannot be converted to quantum efficiency
  • Is there a way to measure cathode responsivity directly?
  • How can we measure the gain of the PMT?
  • Should I add correction for photodetector surface area?

• DMR-16 characterization (varied BPO concentration, polymerization time)
• DMR-17 results (oven, WLS fiber)
• Updated monochromator runs on long Gd-loaded samples with new data
• LCAE sample characterization

• Cf-252 runs, update from previous discussion
  • Sum of PE peaks
  • Runs to do in future?
• Paper progress

• Early July: Paper revision
• Late July: Updated PE Count info
• Early August: Updated muon details

• TB4 board and SiPM characterization
  • SiPM C is bad, not channel 2
  • Several errors in prior analysis, code were misleading
• Cf-252 runs with poly, various triggers
• Various monochromator measurements
• Experimentations with the Test Equity 1000 Temperature Chamber
• DMR-17 Scintillator Samples
• Plans for this week
  • Paper edits
  • Monochromator runs on DMR-16 samples (BPO, polymerization time)
• Reminder: I will be gone on vacation from Friday 7/28 to Friday 8/4

• Results from this past week
  • Baseline subtraction methods
  • Haven't yet implemented new firmware
    • Channel 2 mostly useless
• Things I need from with Ryan:
  • Histogram of number of photoelectrons detected by SiPMs that were produced by gammas from thermal neutron capture on Gd
  • Coincidence percentage: the percentage of detections where more than one photoelectron was detected by more than one detector
  • Percentage of neutron capture events where no photoelectrons are detected by any detector

• See results from last week (if Prisca hasn't already seen them)
• Haven't yet tested new unloaded sample with uncut back

• Fixed Hannah's edits, want to go through paper again myself before D'Ann looks at it
• New samples polymerized - testing time in water bath, BPO concentrations
  • Have not yet polished/tested
• On vacation from 7/28-8/4 and 8/10-8/13

• Monochromator runs on new samples
• Cf-252 runs
  • Go after neutron captures via external triggering
  • Max pulse length = 500 bins (2.4 microseconds)
• New batch of samples is polymerizing (various BPO concentrations, cooling times)
• Muon runs on new samples (not finished)

• Monochromator runs on new samples
  • previous monochromator spectra
• TB4 issues identified
  • Ch. 2 stops working after 2.5 hrs (comes back after about an hour)
  • Add fan under board?
• External trigger, long analysis currently in progress
  • (see reduction code)

• Polished some samples, can see some crazing still on inside face
  • Top and bottom of samples machine quite differently
  • Bottom seems less polymerized than top of samples
• Observed dark room temperature fluctuations: +/- 0.1 C
• TB4 issues: SiPM 3/Ch. 2
• Cf-252 analysis questions
  • Number of counts per second for each channel
  • Total number of photoelectrons detected over 10 microseconds
  • Frequency with which all three channels are 1 PE or more within a certain time window (e.g. 10 nsec coincidence)
• Still have stuff to do from last meeting

Figure: Waveforms for long window, external trigger of TB4 SiPMs
Ch. 0
Ch. 1
Ch. 2

• 7 new samples made
• Fairly low on Gd(i-Pr)₃ after fabrication
• Gd(TMHD)₃ dissolved in sample H after 45 min of sonication
• Received samples from LCAE group
  • Have not been machined or polished yet

• TB4 firmware received from Paul – no idea how to write to board (nor does Hannah)
  • Need Xilinx cable
• Recent runs documentation and procedure are in the process of being written up
• Will try higher thresholds, new trigger possibilities next week

• Need to get .zip files from Ryan's computer
• Will play around with it this weekend, notes in Ryan's email

• Finished Hannah's edits
  • Check legality of discussion in “Gadolinium Compound Trials”, all of the information included had been disclosed in first email communication with LCAE group
• Is Ryan's section ready to Latex?

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March 2, 2017 Scintillator Meeting

LCAE Presentation

CDMS Presentation

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1. Presentation by Ryan and David-Michael
   1. Latest muon results
   2. Computational update

1. Presentation by Ryan and David-Michael
   1. CAD design for gamma catcher
   2. Muon results, comparisons between samples
   3. Computational update
   4. Future plans: Na-22, monochromator

1. Presentation by Ryan and David-Michael
   1. New muon data - results are much closer to old data from Alex and Hannah
   2. Some computational issues resolved

1. Presentation by David-Michael and Ryan (give quick description of topic) link to presentation

2. Discussion about future meeting times (Thursdays around 3:00 or Thursday mornings if Prisca can call in)

3. ??

4. Status update on paper: Dropbox link

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