NKS-B seminar on nuclear forensics in Nordic countries
NKS-B seminar on nuclear forensics in Nordic countries Stefan Isaksson - Gammadata Instrument. Ortecs Nordic representative since 1992. Funded in 1986...
NKS-B seminar on nuclear forensics in Nordic countries Stefan Isaksson - Gammadata Instrument. Ortecs Nordic representative since 1992. Funded in 1986 R&D&M Radon instruments and sensors GPS-based detection system Industrialized the CTBTO SAUNA-system (Noble Gas Analysis) Local HPGe-detector service facility
NKS-B seminar on nuclear forensics in Nordic countries Technologies TGA – Thermo Gravimetric Analysis XRD – X-Ray Diffraction Analysis XRF – X-Ray Fluorescence Analysis TIMS - Thermal Ionization Mass Spectrometry ICP - Inductively Coupled Plasma Mass Spectrometry GD - Glow discharge Mass Spectrometry SIMS - Secondary-Ion Mass Spectrometry SEM - Scanning Electron Microscope Particle Analysis Neutron Activation Alpha Spectroscopy
Gamma Spectroscopy
Gamma Spectroscopy Instrumentation in Nuclear Forensics Outline
• New Profile HPGe detectors – Profile C- and S-series – Profile SP-series
• New Coolers for HPGe detectors – Möbius (LN2 recycler) – ICS (Mechanical cooler)
• Integrated instruments
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Gamma Spectroscopy Instrumentation in Nuclear Forensics Outline
• New Profile HPGe detectors – Profile C- and S-series – Profile SP-series
• New Coolers for HPGe detectors – Möbius (LN2 recycler) – ICS (Mechanical cooler)
• Released in July 2014 • STFC is a new thin contact for P-type detectors that improves low energy ( 10MeV (front) from 40keV > 10MeV (sides) Profile S- (P-type Semi-Planar) “Oversquare” shaped crystal. Crystal dimensions optimized for maximum efficiency when using filters, bottle and pots. Excellent resolution across the energy range. Energy range: from 3keV > 3MeV (front) from 40keV > 10MeV (sides)
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Test 1 and Modelling Results
Observations: •
Measured uncertainties account only for source and counting uncertainties
•
•
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GMX has higher efficiency than GEM due to thinner front contact Profile S has higher efficiency than GMX due to a greater surface area All curves cross at 1332 keV (~50% relative efficiency).
Test 2 Modelling Results
Observations: •
• Filter Paper is 10 cm in diameter
•
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GMX has higher efficiency than GEM due to thinner front contact Profile S has higher efficiency than GMX due to a greater surface area Dip in efficiency at ~14 keV is due to K-edge of Ge material
Profile C- and S- series Models and Specifications
Model No.
S-series GEM-
C-series GEM-
Crystal Energy Resolution (FWHM) Dimension Actual @122 @1.33 Actual 5.9 keV 46 keV Diameter keV MeV Length Warr. Typical (+0/–2 Warr. Warr. Minimum (eV) (eV) mm) (eV) (keV)
New Low Noise Back Contact • The Low Noise Back Contact (LNBC) uses advantages of: – P-type HPGe material. – Semi-Planar crystal geometry – Minimized contact size
• LNBC improves resolution even more in low to medium energies
-
Lithium Stable Thin Contact
GEM-S Core hole
-
Lithium Stable Thin Contact Low Noise Back Contact
GEM-SP Low noise (Proprietary Contact)
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Resolution Results Fe-55 (5.9 and 6.5 keV peaks) 10000
FWHM: 410.32 eV
FWHM: 301.54 eV
9000 8000 7000
Counts
6000 5000 4000 3000 2000 1000
- FWHM measurement at 5.9 keV energy with SP8530 is 302eV (spec is 425), and with S8530 is 410eV (spec 500). - 25% improvement in measured resolution - 15% improvement in specified guaranteed resolution - Better peak differentiation between 5.9 and 6.5 keV peaks
0 4.00
4.50 SP8530
5.00 S8530
5.50
6.00
6.50
7.00
7.50
8.00
Energy (keV)
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More Resolution Results Co-57 (122keV peak)
11000 10000 9000
FWHM: 606.31 eV
FWHM: 533.30 eV
8000
- FWHM measurement at 122 keV energy with SP8530 is 533eV (spec is 630), and with S8530 is 606 eV (spec 700). - 12% improvement in measured resolution - 10% improvement in specified resolution
