Requirements on Neutron Detectors Alternative to He-3 · PDF fileRequirements on Neutron Detectors Alternative to He-3 Fraunhofer ... Fraunhofer Institute for Technological Trend

Fraunhofer INT
Nuclear and Electromagnetic Effects
Wolfgang Rosenstock and Olaf Schumann
Requirements on Neutron Detectors Alternative to He-3
Fraunhofer INT, Euskirchen, Germany Department Nuclear and Electromagnetic Effects
[email protected]
Neutron Detector Technologies Workshop in Vienna (22 24 March 2011)
IAEA short term needs for existing installed SG instrumentation

Fraunhofer INT
Nuclear and Electromagnetic Effects Dr. Wolfgang Rosenstock
Outline
Fraunhofer INT (spheres of work)
Irradiation Facilities at INT
Earlier work performed for IAEA: Qualification of 3He detectors
Concepts for 3He replacement: advantages and drawbacks
Conclusion
nrd 11-10
Dr. Wolfgang Rosenstock

Fraunhofer INT
100 Staff (75 Man Years)including
45 Scientists
Budget ~7.2 Mio including~3,2 Mio Contract Research
Fraunhofer Institute for Technological Trend Analysis INT(Fraunhofer Institut fr naturwissenschaftlich-technische Trendanalysen)

Fraunhofer INT
The Business Areas of INT
Electromagnetic Effects and Threats
Nuclear Effects, Threats and Detection Systems
Trends and Developments in Research and Technology
Planning, Programs and Structures in R&T

Fraunhofer INT
NEMP - Origin and Propagation; Modeling and SimulationEffects of Pulsed High Power Microwaves (HPM)EMC, HPM and NEMP MeasurementManagement of Simulation and Measurement Equipment for Electromagnetic Fields
Electromagnetic Effects and Threats

Fraunhofer INT
Nuclear Security Policy and Detection Techniquesassessment of physical and technological aspects of nuclear threat and security Nuclear Radiation Detection and Identification in the Field
Nuclear Radiation Effects in Electronics and OptoelectronicsRadiation Effects in Fiber Optic and Electronic Systems

Fraunhofer INT
Analysis of the Effects of Ionizing Radiation on Electronic and Optical Components, esp. on Fiber Optic Systems
Management of irradiation facilities for Gamma, Electron, Proton and Neutron Radiation
Qualification of Components and Systems
Identification of Radiation Hard Products
Development of New Sensors for Nuclear Radiation
Advice to Producers and Users of Fiber Optic Systems (Space, High Energy Accelerators, Nuclear Technology Environments and Medicine).
Highlight Nuclear Radiation Effects in Electronics and Optoelectronics
Gamma-Irradiation Facility TK 1000
X-ray flash machineFebetron 705

Fraunhofer INT
Nuclear Security Policy, non-proliferation and arms control, Safeguards
Non-destructive detection and verification of radioactive material as well as fissile material (appropriate for nuclear weapons) on site (surveying cabin NANU)
Measuring car DeGeN Detection of Gammas inclusive Neutrons, search and identification of radioactive and nuclear material
Systems for verification of radioactive and nuclear material, including active interrogation with neutrons by a portable neutron generator and development of mobile neutron radiography
Mobile measuring systems for non-destructive and non-contact detection as well as identification of radioactive or special nuclear material on site.
Highlight Nuclear Security Policy and Detection Techniques

Fraunhofer INT
Available irradiation facilities at INT
several intense Co-60 sources up to 19 TBq ( 4.5 Gy/h in 1 m)
several neutron generators
Thermo D-711 (DD & DT)
Sodern Genie 16C (DD & DT)
Flash X-Ray and Electron Febetron 705
Large variety of isotopic sources
Th-228 , U-238, Am-241, Cm-244
H-3, C-14, Cl-36, Sr-90, Pm-147, Tl-204
Na-22, Mn-54, Co-60, Ba-133, Cs-137, Eu-152+Eu-154+Eu-155
Cf-252, Am/Be, Am/Li
nrd 11-11

Fraunhofer INT
Qualification of 3He-tubes RS-P4-0812-115and RS-P4-0808-212
Performed under the German Support Program (GSP)
Joint Program on the Technical Development and Further Improvement of IAEA Safeguards
Determination of an Optimized Polyethylene Moderator for He-3 Neutron Detectors
RS-P4-0812-115 401.3mm x 26.2mm dia Body: aluminum 1100-F 4.2 bar He-3 1500 V HV Surrounded with 50 mm PE
RS-P4-0808-212 303.0mm x 26.2mm dia Body: stainless steel 304 4.1 bar He-3 1750 V HV Surrounded with 50 mm PE
nrd 11-12

Fraunhofer INT
Experimental Setup: Evaluation of Gamma Sensitivity
60Co Source
He-3 Detectorwith PE moderator
Co-60 source
Activity: 17.2 TBq
Different distances to vary flux
Cf-252
Activity: 1.4 MBq
Emission: 1.5 105 n/s in 4Placed 1.3 m from He-3 tube
Flux: 0.75 n/(cm2 s)
PNPI Electronics
Preamplifier, shaping amplifier and threshold
Threshold from 0 to 1.2 V
nrd 11-13

Fraunhofer INT
Neutron Pulse Hight Spectrum of He-3 Tube
0
20
40
60
80
100
120
0 200 400 600 800 1000 1200 1400 1600
Pulse Height [Channel No.]
Cou
nts
/ 300
s
n + 3He 3H + p + 764 keV
Full energydeposited byionisation
3H energy lost in tube wall,only p seen
nrd 11-14

Fraunhofer INT
Comparison of Neutron / Gamma only spectrum
1
10
100
1000
10000
100000
0 100 200 300 400 500 600 700 800
Cou
nts
/ 100
s
Gamma, 0.7 Gy/h
Neutrons
Channels overlapDiscrimination bythreshold
nrd 11-15

Fraunhofer INT
Combined Neutron / Gamma spectra
1
10
100
1000
10000
100000
0 100 200 300 400 500 600 700 800
Cou
nts
/ 100
s
n
Neutron + Gamma
Pile-up due tosimultaneous n+
Channels overlap,Discrimination bythreshold
nrd 11-16

Fraunhofer INT
Effect of amplifier threshold
1
10
100
1000
10000
100000
1000000
0 100 200 300 400 500 600 700 800
Cou
nts
/ 300
s
No threshold
500 mV800 mV
Gammas could besuppressed bythreshold value
Reduces absolutefficiency for n
nrd 11-17

Fraunhofer INT
High Gamma dose rate
At 5.77 Gy/h (former slides 0.7 Gy/h) Gammas clearly dominate
1
10
100
1000
10000
0 100 200 300 400 500 600 700 800 900
Cou
nts
/ 300
s
Neutrons
Gamma +Neutrons(red)
No morediscriminationpossible
nrd 11-18

Fraunhofer INT
Efficiency vs. Threshold
0
10
20
30
40
50
60
70
80
90
100
110
0 200 400 600 800 1000 1200
Discriminator Threshold [mV]
Rel
ativ
e N
eutr
on C
ount
ing
Effic
ienc
y [%
]
0.3 Gy/h0.7 Gy/h1.29 Gy/h5.77 Gy/h
Gamma Dose Rate
Up to a Gammadose rate of 1.3 Gy/hcompleteneutron/gammadiscrimination possible
}{}{}{
++
=n
nEff
nrd 11-19

Fraunhofer INT
Influence of neutron flux and neutron energy
50
60
70
80
90
100
110
0 200 400 600 800 1000 1200
Discriminator Threshold [mV]
Rel
ativ
e N
eutro
n C
ount
ing
Effic
ienc
y [%
]
Cf-252
Am-Be
Gamma Dose Rate: 0.7 Gy/h
Am/Be source with 106.6 GBqFlux: 29.7 n/cm2 s40 times the flux of Cf-252
Above threshold of ~ 700 mV no change in discrimination
0
50
100
150
200
250
300
350
400
0 200 400 600 800 1000 1200 1400 1600
Cou
nts
/ 100
s
Neutron flux39 n/cm2s
Neutron flux280 n/cm2s
14 MeV DT neutrons, no additional GammaFlux: 39 and 280 n/cm2s
Large pile-up effects
Pile-up
nrd 11-20

Fraunhofer INT
Summary of performed experimentsGamma and Neutron irradiation of IAEA employed He-3 counters and electronic
Determination of relative and absolute ef

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Requirements on Neutron Detectors Alternative to He-3 · PDF fileRequirements on Neutron Detectors Alternative to He-3 Fraunhofer ... Fraunhofer Institute for Technological Trend