CDMS II Veto Panel Prototyping


The Test Panels & PMTs

BICRON BC-408 Plastic Scintillator
Panel Dimensions
The Hamamatsu R329-02 PMTs
Range: 300 to 650 nm (peak @ 420 nm, very blue)
Bialkali Photocathode & Borosilicate K-free Window Glass
Suggested Supply Voltage = 1500 Vdc
Quoted Typical Gain = 1.1x10^6
The E4512-501 Hamamatsu Base
Dark Currents With High Voltage @ 1500 V
Quoted Typical = 6 nA
Dark Currents For New PMTs
Hamamatsu's QuoteOur Measurement
Tube #RC89801.40 nA1 to 2 nA
Tube #RC89640.97 nA0.3 to 0.6 nA
Tube #RC91686.20 nA5 to 7 nA
Tube #RC90180.42 nA1 to 3 nA
Tube #RC89473.00 nA7 to 8 nA
Tube #RC89820.82 nA0.2 to 0.6 nA


Co60 Current Measurements (measurements made with optical grease joints)

The Measurement Grid
Experimental Setup
The Results
Arrangement #1 (A1)
Contour Plot With Actual Current Measurements
Normalized & Plotted Using A1 Scale
Normalized & Plotted Using A2 Scale
Normalized & Plotted Using A3 Scale
Arrangement #2 (A2)
Contour Plot With Actual Current Measurements
Normalized & Plotted Using A1 Scale
Normalized & Plotted Using A2 Scale
Normalized & Plotted Using A3 Scale
Arrangement #3 (A3)
Contour Plot With Actual Current Measurements
!! New Measurement With Improved Optical Joint (Absolute #'s are larger, but trends are basically the same)!!
Normalized & Plotted Using A1 Scale
Normalized & Plotted Using A2 Scale
Normalized & Plotted Using A3 Scale


ADC Spectra (measurements made with 30 min epoxy glue joints)

Experimental Setup
Results For Phototube # RC8980 (operating @ 1000 V)
Trial #1
Angled & Non-Angled ADC Histogram
A Close Up of the Muon Peaks
Trial #2 - Incomplete due to broken phototube
Non-Angled ADC Histogram
A Close Up of the Muon Peak
Results For Phototube # RC9018 (operating @ 1100 V)
Trial #1
Angled & Non-Angled ADC Histogram
A Close Up of the Muon Peaks
Trial #2
Angled & Non-Angled ADC Histogram
A Close Up of the Muon Peaks
Some Spectra From The SUF Veto For Comparison
North West, North East & East Veto Paddles
West, South Top & South Bottom Veto Paddles
Top South, Top North & Crack Paddles


Muon Efficiency and ADC Measurements (measurements made with optical grease joints)

The Measurement Grid
Muon Detection Efficiency Experimental Setup
Results For Arrangemet #1
A few tenths of a percent inefficiency expected from accidentals
A1 thus has a statistically significant and unacceptable inefficiency
Muon ADC Measurements Experimental Setup
Results For Arrangement #2
Variation of the Muon Peak For A2
ADC Muon Spectrum For Grid Point #1
ADC Muon Spectrum For Grid Point #2
ADC Muon Spectrum For Grid Point #3
ADC Muon Spectrum For Grid Point #4
ADC Muon Spectrum For Grid Point #5
ADC Muon Spectrum For Grid Point #6
ADC Muon Spectrum For Grid Point #7
ADC Muon Spectrum For Grid Point #8
ADC Muon Spectrum For Grid Point #9
Results For Arrangement #3
Variation of the Muon Peak For A3
ADC Muon Spectrum For Grid Point #1
ADC Muon Spectrum For Grid Point #2
ADC Muon Spectrum For Grid Point #3
ADC Muon Spectrum For Grid Point #4
ADC Muon Spectrum For Grid Point #5
ADC Muon Spectrum For Grid Point #6
ADC Muon Spectrum For Grid Point #7
ADC Muon Spectrum For Grid Point #8
ADC Muon Spectrum For Grid Point #9
Muon Peak Variation: A2 vs. A3
If the above plot is difficult to read try this one instead


Determination of Light Loss in A3 Compared to A2

The First Attempt Using Optical Grease
The Quality of This Test Was Subject To Possibly Poor Optical Joints
Co60 Current Measurements Using The Same PMT
A2 Contour Plot With Currents
A3 Contour Plot With Currents
A2 Contour Plot Normalized
A3 Contour Plot Normalized & Scaled to the above A2 plot
The Resulting Loss Function For A3
The Second Attempt Using 30min Epoxy & A New Gluing Fixture
Phototube # RC8980
Co60 Current Comparison
Trial#1
A2 Currents & A3 Currents
The Resulting Loss Function
Trial#2-Incomplete due to broken phototube
A2 Currents
ADC Muon Spectra Comparison
Trial#1
Position #4 (far from PMT)
Position #5 (middle of test panel)
Position #6 (near PMT)
A Summary Graph
Trial#2 - Cancelled due to broken phototube
Phototube # RC9018
Co60 Current Comparison
Trial#1
A2 Currents & A3 Currents
The Resulting Loss Function
Trial#2
A2 Currents & A3 Currents
The Resulting Loss Function
Average Loss Function
ADC Muon Spectra Comparison
Trial#1
Position #4 (far from PMT)
Position #5 (middle of test panel)
Position #6 (near PMT)
A Summary Graph
Trial#2
Position #4 (far from PMT)
Position #5 (middle of test panel)
Position #6 (near PMT)
A Summary Graph
Average Loss Function


Test of Glue Joint Reproducibility

Trials 1 & 2 represent physically different glue joints
Percent differences between trials 1 & 2 are given to the right in RED
A Picutre of the Gluing Fixture
The Fixture in Action
Comparison of Co60 current measurements for 2 different glue joints
Phototube # RC9018
Non-Angled Light Guide (Mean Difference = 1.94%)
Angled Light Guide (Mean Difference = 3.4%)
Comparison of full ADC spectra for 2 different glue joints
Phototube # RC8980
Non-Angled Light Guide (1.7%)
Phototube # RC9018
Non-Angled Light Guide (0.13%)
Angled Light Guide (5%)
Comparison of Muon ADC spectra for 2 different glue joints
Phototube # RC9018
Non-Angled Light Guide Far Position (3.7%)
Angled Light Guide Far Position (0.7%)
Non-Angled Light Guide Middle Position (1.1%)
Angled Light Guide Middle Position (0.5%)
Non-Angled Light Guide Near Position (4.1%)
Angled Light Guide Near Position (1.1%)
Thank You Susanne Kyre and Dan Callahan for an outstanding gluing fixture!!!