quaesta instruments tucson arizona founded in 2008 staff: 10 electronic devices: radiation detection...
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Quaesta Instruments
• Tucson Arizona• Founded in 2008• Staff: 10• Electronic devices:
• radiation detection• environmental monitoring• data logging• telemetry
• Off-the-shelf and custom products
• Neutron Pulse Monitors- Proportional gas detectors
• Data logging devices
• Environmental sensors
• Mobile neutron detectors
• Soil moisture monitoring stations (radiation based)
Products
Neutron Pulse MonitorNPM
Pulse Height Spectrum
Classical 3He spectrum digitized over 128 bins
Plateau Method
Counting Plateau
Lower discriminator
Plateau Method
• Requires many points for good resolution on discriminator set point• For low count rates, time per point may be large
LowerDiscriminator
UpperDiscriminator
Multichannel Analyzer
Setting the Discriminator Levels
With a Multichannel Analyzer (MCA)
Setting the Discriminator Levels
With a Multichannel Analyzer (MCA)
Setting the Discriminator Levels
With a Multichannel Analyzer (MCA)
Setting the Discriminator Levels
With a Multichannel Analyzer (MCA)
Setting the Discriminator Levels
With a Multichannel Analyzer (MCA)
Setting the Discriminator Levels
With a Multichannel Analyzer (MCA)
Setting the Discriminator Levels
With a Multichannel Analyzer (MCA)
Setting the Discriminator Levels
With a Multichannel Analyzer (MCA)
Setting the Discriminator Levels
With a Multichannel Analyzer (MCA)
Setting the Discriminator Levels
With a Multichannel Analyzer (MCA)
Setting the Discriminator Levels
With a Multichannel Analyzer (MCA)
Setting the Discriminator Levels
With a Multichannel Analyzer (MCA)
Valley Peak
Setting the Discriminator Levels
With a Multichannel Analyzer (MCA)
PeakValley
Real Spectra
0 20 40 60 80 100 120 1400
500
1000
1500
2000
2500BF3 Gas Proportional Tube,
Pulse Height Spectrum
Relative Pulse Height
# of
Cts
"Valley"
Wall-Effect Continuum
Gamma and Electronic Noise Generated Counts
Excited State Peak
Ground State Peak
Real Spectra
0 20 40 60 80 100 120 1400
500
1000
1500
2000
2500
3000
3500 Boron-Lined GE Reuter-Stokes TubePulse Height Spectrum
Relative Pulse Height
# of
Cts
Lithium-7 Recoil Events Alpha particle Events
Real Spectra
0 20 40 60 80 100 120 1400
50
100
150
200
250
300
He3 Tube Hgms indicated detecor problem during system QA testing. The manu-facturer reworked the tube.
Hgm # 0, 8/10/2011,04:47
Hgm # 1, 8/10/2011,05:12
Hgm # 2, 8/10/2011,06:12
Hgm # 3, 8/10/2011,07:12
Hgm # 4, 8/10/2011,08:12
Hgm # 5, 8/10/2011,09:12
Hgm # 6, 8/10/2011,10:12
Hgm # 7, 8/10/2011,11:12
Relative Pulse Height
# of
Cts
, Sca
led
He3 tube failure under thermal cycle testing
Example of Field Neutron Detector System Failure, BF3 DetectorTime Series
85 87 89 91 93 95 970
200
400
600
800
1000
1200
Customer Supplied Data, BF3 Detector, Deployed in Remote Field Location, Data Telemetry
via Iridium Satellite
Thermal Neutrons
Day of Year, 2011, UTC
Cts
/ H
r
0 20 40 60 80 100 120 1400
50
100
150
200
250
300
Customer Supplied Data, BF3 Detector, Remote Location, Data Telemetry via Iridium Satellite,
Hgms from Days 87 and 88 -> System OK!
Day 87Day 88
Relative Pulse Height
# of
Cts
(Sca
led)
Histograms before and after suspicious neutron counts
0 20 40 60 80 100 120 1400
50
100
150
200
250
300
Customer Supplied Data, BF3 Detector, Remote Location, Data Telemetry via Iridium Satellite,
Hgms from Days 91 and 92 -> System Problem!
Day 91
Day 92
Relative Pulse Height
# of
Cts
(Sca
led)
DirtyConnector
NPM Architecture
Value of a Digital NPM
• Computer interface
• MCA & spectra - optimization
• Monitoring
• Data logging
Data Logger
• Analog & digital I/Os• Relays• USB, RS-232, SDI-12• SD cards• Connect to NPMs• External Sensors• Telemetry
Remote Monitoring & Mobile Detectors
Remote Monitoring & Mobile Detectors
Remote Monitoring & Mobile Detectors
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.70
50
100
150
200
250
300
350
400
0
10
20
30
40
50
60
70Univ of Arizona, He3 Roving Instrument, Channel 2 Humidity Intrusion
N1CN2CDeg CInstrument Relative Humidty %
Day of Month (Jul 2013)
Coun
ts p
er 1
min
ute
Inte
rval
Tem
pera
ture
and
RH%
Roving Detector Data
0 20 40 60 80 100 120 1400
50
100
150
200
250
300Univ of Arizona, He3 Roving Instrument, Channel 2, Humidity Intrusion
Before Humidity Intrusion, System OK
During Humidity Intrusion
After Humidity Intrusion, System Recovered
Relative Pulse Height
Scal
ed #
of C
ount
sRoving Detector Data
Noise produced by humidity
Remote Monitoring & Mobile Detectors
IAEA: Mobile Unit for Neutron Detection (MUNDs)
IAEA: MUNDs
NPM
NPM: Ethernet + 15MHz input pulse counter
Soil Moisture Monitoring
Average Soil Moisture
600 meters
Field scale soil moisture monitoring using cosmic ray neutrons
Measures fast and slow neutrons
Pressure & Humidity dependent
Soil Moisture Monitoring
Challenges
• Low power consumption • Very low count rate• High stability in calibration required wide temperature range• High resolution pressure meas
Soil Moisture Monitoring
Soil Moisture Monitoring
Alpine Location
New Stuff
Neutron Detector Arrays
Neutron Detector Arrays
