Los Alamos
UNCLASSIFIED
LA-UR-09-02048
Progress Toward the Development of Microcalorimeters for Ultra-High Resolution Alpha Spectrometry Los Alamos A.A. Plionis, A.L. Klingensmith, J.H. Rim, E.M. Bond, W.A. Moody, D.E. Dry, S.P. LaMont, M.K. Bacrania, M.P. Croce, M.W. Rabin National Institute of Standards and Technology J.N. Ullom, R.D. Horansky, V. Kotsubo
UNCLASSIFIED Operated by the Los Alamos National Security, LLC for the DOE/NNSA
UNCLASSIFIED
Physics • Calorimetry measures the heated deposited by an event
• Microcalorimeters operate at ~100 mK
•
Allows for ultra-high resolution spectrometry of various forms of radiation
• Currently – 1.06 keV resolution for α – 22 eV resolution for γ
UNCLASSIFIED Operated by the Los Alamos National Security, LLC for the DOE/NNSA
UNCLASSIFIED
Alpha Particle Microcalorimeter Design Cu isolated from Si wafer by SiN
TES
Cu
Si wafer
Sn absorber
0.25’’
SiN
Post
Sn TES
Si wafer UNCLASSIFIED Operated by the Los Alamos National Security, LLC for the DOE/NNSA
Cu
UNCLASSIFIED
UNCLASSIFIED Operated by the Los Alamos National Security, LLC for the DOE/NNSA
UNCLASSIFIED
Alpha Spec: Nuclear Forensic Context 103 grams Pu
10-15 grams Pu
10-6 grams Pu Alpha Spec Range 10-6 – 10-12 g
Attribution Waste Characterization Environmental Environmental MPC&A Measurements Safeguards
Weapons
Titration Calorimetry
Neutron counting
Alpha Spec
Gamma Spec
Total Pu
Pu Activity UNCLASSIFIED
Operated by the Los Alamos National Security, LLC for the DOE/NNSA
ICP-MS TIMS Isotope Ratios
UNCLASSIFIED
Motivation: Nuclear Materials Analysis •
alpha spectroscopy is a powerful tool for trace actinide measurements -
environmental monitoring nuclear safeguards medical assay
•
alpha branching ratios higher than gamma
•
~ 8 keV resolution limit of Si detectors has consequences: –
elemental overlaps
–
cannot split 239Pu/240Pu
used for smaller samples (µg-pg)
slow and expensive wet chemistry to separate elements slow and expensive mass spectrometry 2500 Typical Pu Alpha Spectrum 239 Pu Alpha Particles 240 Pu Alpha Particles
data
2000
Counts
239Pu 240Pu
1500
1000
500
UNCLASSIFIED Operated by the Los Alamos National Security, LLC for the DOE/NNSA
0 4800
4900
5000
5100
Energy (keV)
5200
5300
5400
Processing Steps
Time (days)
dissolve or leach
1 2
group actinide separation
3
dry / ash samples
separate individual actinides
1. Resolve elemental overlaps Alpha spectrometry on mixed-actinide samples
alpha spectrometry
4 5 6 7
redissolve actinides radiochemistry
2. Resolve isotopic overlaps Alpha spectrometry on mixed-isotope samples
8 9 10 11
mass spectrometry
12 13 14
UNCLASSIFIED
Technical Approach • Fabricate suitable alpha-emitting counting sources for measurement by microcalorimetry – Negligible loss of alpha particle energy by self-attenuation – Ultra-thin, uniform layer of radionuclide(s)
• Surface analysis of counting sources – – – – –
Fission track analysis (FTA) Scanning electron microscopy (SEM) Energy Dispersive X-ray Spectroscopy (EDX) Infra-red mapping Etc.
• Counting source preparation from complex sample matrices
UNCLASSIFIED Operated by the Los Alamos National Security, LLC for the DOE/NNSA
UNCLASSIFIED
Electrodeposition Basics H O
Pt wire (anode)
+
planchet (cathode)
(H2O)4 • UO2
-
UO2 • (H2O)4
O H n
UNCLASSIFIED Operated by the Los Alamos National Security, LLC for the DOE/NNSA
UNCLASSIFIED
Surface Characterization: SEM
•
Scanning electron microscope images of titanium planchets
•
Before electrodepotion (Left). After electrodeposition with uranium (Right)
UNCLASSIFIED Operated by the Los Alamos National Security, LLC for the DOE/NNSA
UNCLASSIFIED
With Increased U Deposition, Large High Z Spheres
UNCLASSIFIED Operated by the Los Alamos National Security, LLC for the DOE/NNSA
Slide 11
UNCLASSIFIED
Surface Characterization: FTA • Distribution of fissile material (235U, 239Pu, etc.)
• Irradiations done at Penn State • Film in contact with sample is microscopically etched by fission recoil nuclei
• Clusters of tracks (starburst pattern) indicate inhomogeneities
• Number of tracks per quadrant is nearly identical
UNCLASSIFIED Operated by the Los Alamos National Security, LLC for the DOE/NNSA
UNCLASSIFIED
Results to Date: 239Pu/240Pu Measurement Si Actual Ratio
µCal
No systematic error in microcalorimeter
UNCLASSIFIED Operated by the Los Alamos National Security, LLC for the DOE/NNSA
UNCLASSIFIED
Results to Date: 238Pu/241Am Measurement Si Actual Ratio
241Am 238Pu
241Am 238Pu
µCal
UNCLASSIFIED Operated by the Los Alamos National Security, LLC for the DOE/NNSA
UNCLASSIFIED
Future Studies • Modeling of alpha particle energy loss within sample matrix – Monte-Carlo based radiation transport codes – Require more detailed information on analyte/non-analyte deposition patterns
• Atomic force microscopy – Topographical mapping of sample surface
• Synchrotron x-ray tomography – Ultra-high resolution elemental characterization – Few facilities and limited beam time
UNCLASSIFIED Operated by the Los Alamos National Security, LLC for the DOE/NNSA
UNCLASSIFIED
Credits Los Alamos M. Bacrania E. Bond K. Chesson* M. Croce* D. Dry N. Hoteling** A. Hoover P. Hypes P. Karpius S. Lamont A. Plionis** J. Rim* C. Rudy M. Smith*** D. Tournear*** D. Vo M. Rabin (PI)
NIST J. Beall S. Cho R. Doriese W. Duncan L. Ferreira G. Hilton R. Horansky K. Irwin V. Kotsubo B. Mates* G. O’Neil* N. Miller* C. Reintsema E. Sassi* D. Schmidt J. Ullom L. Vale Y. Xu UNCLASSIFIED
Operated by the Los Alamos National Security, LLC for the DOE/NNSA
NASA C. A. Kilbourne J. M. King F. S. Porter Univ. ofDenver B. Zink N. Jethava** Star Cryo R. Cantor XIA LLC W. Hennig Hui Tan W. Warburton * ** ***
student post-doc promoted to program mgmt.
LA-UR-09-02048
Progress Toward the Development of Microcalorimeters for Ultra-High Resolution Alpha Spectrometry Los Alamos A.A. Plionis, A.L. Klingensmith, J.H. Rim, E.M. Bond, W.A. Moody, D.E. Dry, S.P. LaMont, M.K. Bacrania, M.P. Croce, M.W. Rabin National Institute of Standards and Technology J.N. Ullom, R.D. Horansky, V. Kotsubo
UNCLASSIFIED Operated by the Los Alamos National Security, LLC for the DOE/NNSA
UNCLASSIFIED
Physics • Calorimetry measures the heated deposited by an event
• Microcalorimeters operate at ~100 mK
•
Allows for ultra-high resolution spectrometry of various forms of radiation
• Currently – 1.06 keV resolution for α – 22 eV resolution for γ
UNCLASSIFIED Operated by the Los Alamos National Security, LLC for the DOE/NNSA
UNCLASSIFIED
Alpha Particle Microcalorimeter Design Cu isolated from Si wafer by SiN
TES
Cu
Si wafer
Sn absorber
0.25’’
SiN
Post
Sn TES
Si wafer UNCLASSIFIED Operated by the Los Alamos National Security, LLC for the DOE/NNSA
Cu
UNCLASSIFIED
UNCLASSIFIED Operated by the Los Alamos National Security, LLC for the DOE/NNSA
UNCLASSIFIED
Alpha Spec: Nuclear Forensic Context 103 grams Pu
10-15 grams Pu
10-6 grams Pu Alpha Spec Range 10-6 – 10-12 g
Attribution Waste Characterization Environmental Environmental MPC&A Measurements Safeguards
Weapons
Titration Calorimetry
Neutron counting
Alpha Spec
Gamma Spec
Total Pu
Pu Activity UNCLASSIFIED
Operated by the Los Alamos National Security, LLC for the DOE/NNSA
ICP-MS TIMS Isotope Ratios
UNCLASSIFIED
Motivation: Nuclear Materials Analysis •
alpha spectroscopy is a powerful tool for trace actinide measurements -
environmental monitoring nuclear safeguards medical assay
•
alpha branching ratios higher than gamma
•
~ 8 keV resolution limit of Si detectors has consequences: –
elemental overlaps
–
cannot split 239Pu/240Pu
used for smaller samples (µg-pg)
slow and expensive wet chemistry to separate elements slow and expensive mass spectrometry 2500 Typical Pu Alpha Spectrum 239 Pu Alpha Particles 240 Pu Alpha Particles
data
2000
Counts
239Pu 240Pu
1500
1000
500
UNCLASSIFIED Operated by the Los Alamos National Security, LLC for the DOE/NNSA
0 4800
4900
5000
5100
Energy (keV)
5200
5300
5400
Processing Steps
Time (days)
dissolve or leach
1 2
group actinide separation
3
dry / ash samples
separate individual actinides
1. Resolve elemental overlaps Alpha spectrometry on mixed-actinide samples
alpha spectrometry
4 5 6 7
redissolve actinides radiochemistry
2. Resolve isotopic overlaps Alpha spectrometry on mixed-isotope samples
8 9 10 11
mass spectrometry
12 13 14
UNCLASSIFIED
Technical Approach • Fabricate suitable alpha-emitting counting sources for measurement by microcalorimetry – Negligible loss of alpha particle energy by self-attenuation – Ultra-thin, uniform layer of radionuclide(s)
• Surface analysis of counting sources – – – – –
Fission track analysis (FTA) Scanning electron microscopy (SEM) Energy Dispersive X-ray Spectroscopy (EDX) Infra-red mapping Etc.
• Counting source preparation from complex sample matrices
UNCLASSIFIED Operated by the Los Alamos National Security, LLC for the DOE/NNSA
UNCLASSIFIED
Electrodeposition Basics H O
Pt wire (anode)
+
planchet (cathode)
(H2O)4 • UO2
-
UO2 • (H2O)4
O H n
UNCLASSIFIED Operated by the Los Alamos National Security, LLC for the DOE/NNSA
UNCLASSIFIED
Surface Characterization: SEM
•
Scanning electron microscope images of titanium planchets
•
Before electrodepotion (Left). After electrodeposition with uranium (Right)
UNCLASSIFIED Operated by the Los Alamos National Security, LLC for the DOE/NNSA
UNCLASSIFIED
With Increased U Deposition, Large High Z Spheres
UNCLASSIFIED Operated by the Los Alamos National Security, LLC for the DOE/NNSA
Slide 11
UNCLASSIFIED
Surface Characterization: FTA • Distribution of fissile material (235U, 239Pu, etc.)
• Irradiations done at Penn State • Film in contact with sample is microscopically etched by fission recoil nuclei
• Clusters of tracks (starburst pattern) indicate inhomogeneities
• Number of tracks per quadrant is nearly identical
UNCLASSIFIED Operated by the Los Alamos National Security, LLC for the DOE/NNSA
UNCLASSIFIED
Results to Date: 239Pu/240Pu Measurement Si Actual Ratio
µCal
No systematic error in microcalorimeter
UNCLASSIFIED Operated by the Los Alamos National Security, LLC for the DOE/NNSA
UNCLASSIFIED
Results to Date: 238Pu/241Am Measurement Si Actual Ratio
241Am 238Pu
241Am 238Pu
µCal
UNCLASSIFIED Operated by the Los Alamos National Security, LLC for the DOE/NNSA
UNCLASSIFIED
Future Studies • Modeling of alpha particle energy loss within sample matrix – Monte-Carlo based radiation transport codes – Require more detailed information on analyte/non-analyte deposition patterns
• Atomic force microscopy – Topographical mapping of sample surface
• Synchrotron x-ray tomography – Ultra-high resolution elemental characterization – Few facilities and limited beam time
UNCLASSIFIED Operated by the Los Alamos National Security, LLC for the DOE/NNSA
UNCLASSIFIED
Credits Los Alamos M. Bacrania E. Bond K. Chesson* M. Croce* D. Dry N. Hoteling** A. Hoover P. Hypes P. Karpius S. Lamont A. Plionis** J. Rim* C. Rudy M. Smith*** D. Tournear*** D. Vo M. Rabin (PI)
NIST J. Beall S. Cho R. Doriese W. Duncan L. Ferreira G. Hilton R. Horansky K. Irwin V. Kotsubo B. Mates* G. O’Neil* N. Miller* C. Reintsema E. Sassi* D. Schmidt J. Ullom L. Vale Y. Xu UNCLASSIFIED
Operated by the Los Alamos National Security, LLC for the DOE/NNSA
NASA C. A. Kilbourne J. M. King F. S. Porter Univ. ofDenver B. Zink N. Jethava** Star Cryo R. Cantor XIA LLC W. Hennig Hui Tan W. Warburton * ** ***
student post-doc promoted to program mgmt.
