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Riham MARIAM, Matias RODRIGUES , Martin LOIDL CEA, LIST Laboratoire National Henri Becquerel

Riham MARIAM, Matias RODRIGUES , Martin LOIDL CEA, LIST Laboratoire National Henri Becquerel. First measurements of detailed absolute emission intensities of L X-ray emitted by actinides using a MMC. 18 th International Workshop on Low Temperature Detectors. matias.rodrigues@cea.fr.

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Riham MARIAM, Matias RODRIGUES , Martin LOIDL CEA, LIST Laboratoire National Henri Becquerel

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  1. Riham MARIAM, Matias RODRIGUES, Martin LOIDL CEA, LIST Laboratoire National Henri Becquerel First measurements of detailed absolute emission intensities of L X-ray emitted by actinides using a MMC. 18th International Workshop on Low Temperature Detectors matias.rodrigues@cea.fr

  2. Radioactive material analysis by photon spectrometry • X-ray and gamma spectrometry : • Many fields of applications use photon spectrometry in particular of actinides • Nuclear fuel cycle • Non-proliferation of nuclear weapons • Metrology of ionizing radiations • However the knowledge of the photon emission intensity (uncertainties > 1%) is a fundamental limit to the precision of measurements Radioactive material Photon live time [s] : FEP detection efficiency : Emission intensity [photons / disintegration] Spectrometer 18th Workshop on LowTemperature Detectors| Milano | 22-26/07/2019 | Matias RODRIGUES

  3. Knowledge of L X-ray • emission intensities of actinides gand X L-rays 10 - 100 keV : ~ 0.01 to 10 photons / 100 disintegrations •  They are only few and old measurements • Calculations and measurements are not always consistent • The L X-ray lines are not detailed 18th Workshop on LowTemperature Detectors| Milano | 22-26/07/2019 | Matias RODRIGUES

  4. Example: emission intensities of Pu-238 Recommended values evaluated by the DDEP (Decay Data Evaluation Project) ~ 10 evaluated measurements of L X-rays  recommended value 10.63 (8) % XL Deviation from recommended value (%) 18th Workshop on LowTemperature Detectors| Milano | 22-26/07/2019 | Matias RODRIGUES

  5. Difficulties to measure L X-ray intensities • with semiconductor spectrometers live time [s] : FEP detection efficiency : Intensity [photons / decay] Source Photon • Using semiconductor spectrometers: • Insufficient energy resolution to separate the L X-ray • Correction of the detection efficiency by 15% 241Am L X-ray spectrum Spectrometer >15% La Lb Lg Li 18th Workshop on LowTemperature Detectors| Milano | 22-26/07/2019 | Matias RODRIGUES L X-ray

  6. A dedicated MMC for Photon spectrometry • Of L X-Ray of actinides Au-Ag absorber KIP Heidelberg 1 mm2 Sensor Thermal bath T0 ~ 10 mK SQUID V V Input coil • 4 absorbers of 1 mm2 • 50 mm of Au + 17 mm of Ag thick • Intrinsic efficiency > 99% between 10-25 keV • 10 – 20 s-1 (td ≈ 4 ms) • Energy resolution FWHM of 26 eV MMC with 4 pixels Thermal link AuAg absorber SQUID chip 2 mm 18th Workshop on LowTemperature Detectors| Milano | 22-26/07/2019 | Matias RODRIGUES

  7. FULL ENERGY PEAK detection efficiency calibration USING 241Am AND MC SIMULATIONS Source Stainlesssteel Be window Z Z pixel [PhD thesis of Riham MARIAM] Y Y X MMC Pb shield W collimator W collimator 40 mm thick Be window 15 mm • 10 keV < E < 25 keV ~ 0.7% uncertainty • < 10 keV ~ 4% uncertainty at 2 keV • > 25 keV ~ 1.2% to 2.4% uncertainty Radioactive source Stainlesssteel source support 18th Workshop on LowTemperature Detectors| Milano | 22-26/07/2019 | Matias RODRIGUES

  8. Measured radionuclides 18th Workshop on LowTemperature Detectors| Milano | 22-26/07/2019 | Matias RODRIGUES

  9. Additional corrections for the absolute emission measurements • Correction of self-absorption in the source by MC simulation: • 239Pu source thickness ~4.5 µm • 237Np source thickness ~6.2 µm • Efficiency transfer by MC simulation: • Source diameter of 12 mm instead of 6 mm  -15.6% correction • Shift of the source position •  -1.4% for 238Pu •  -0.8% for 244Cm [PhD thesis of Riham MARIAM] Activity distribution of 238Pu Detection efficiencymap 12 mm • Correction of -3.1% for 238Pu • Correction of +3.1% for 244Cm • Correction of -1.8% for 237Np

  10. Comparison of total L X-ray emission intensities 238Pu 10.76 (10) / 100 decays Preliminary 244Cm 237Np 9.12 (12) / 100 decays 63.0 (9) / 100 decays Deviationwithrecommended value (%) 18th Workshop on LowTemperature Detectors| Milano | 22-26/07/2019 | Matias RODRIGUES

  11. 10000 1000 Counts per channel 100 10 1 11000 12000 13000 14000 15000 16000 17000 18000 19000 20000 21000 22000 Energy (eV) • L X-ray spectra with a high level of details 238Pu FWHM energy resolution of between 25 and 45 eV  measurements of about 30 L X-ray emission intensities 18th Workshop on LowTemperature Detectors| Milano | 22-26/07/2019 | Matias RODRIGUES

  12. Individual absolute L X-ray emission intensities Preliminary 18th Workshop on LowTemperature Detectors| Milano | 22-26/07/2019 | Matias RODRIGUES

  13. 10000 50000 10000 1000 1000 Counts per channel 100 100 10 10 1 18600 19600 20600 21600 14600 15600 16600 17600 Energy (eV) Energy (eV) XLi GROUP EMISSION INTENSITIES XL3 XLgof 238Pu XLbof 238Pu XL2 XL1 The Li-X lines separated individually  Determination of the and the XLi groups • Both 238Pu and 239Pu decay to U • But the relative XLi intensities depend on the isotopes Ni :primary vacancies created by IC 18th Workshop on LowTemperature Detectors| Milano | 22-26/07/2019 | Matias RODRIGUES

  14. 5000 10000 1000 1000 Counts per channel 100 Counts per channel 100 10 10 12600 13100 13600 14100 12800 13300 13800 14300 Energy (eV) Energy (eV) • L X-Ray Satellite intensities 238Pu 237Np , 233Pa U La2 Solid line : diagram Dashed line : satellites U La1(L3-M5) Pa La1 U La1 (L3-M5) U La2 Pa La2 233Pa: La1(Sat)/La1(Diag) = 18.7% 238Pu: La1(Sat)/La1(Diag) = 2.2% M5 M1 L3 L2 L1 X-ray satellite E’(L3M4-M4M5) > E(L3-M5) Shift up to 100 eV CosterKronig transition L3-L1M4 18th Workshop on LowTemperature Detectors| Milano | 22-26/07/2019 | Matias RODRIGUES

  15. Conclusions • Calibration of the FEP detection efficiency with 0.7% uncertainty between 10 and 25 keV • Measurement of L X-ray spectra from 8 radionuclideswith FWHM energy resolution of 25 – 45 eV up to 60 keV • Total L X-ray emission intensities in agreement with recommended values • About 30 absolute individual emission intensities for 4 actinides • Uncertainties dominated by sources positioning and activity inhomogeneity can be improved • New X-ray MMC detector for photon emission intensities < 10 keV  MetroMMC project, Poster [122] RANITZSCH,Phillipp Chung-On Perspectives 18th Workshop on LowTemperature Detectors| Milano | 22-26/07/2019 | Matias RODRIGUES

  16. Thank you for your attention

  17. LIVE time determination using extendable dead time Pile-up on the pulse decay Raw stream Filtered stream Pulse start Pulse stop • Dead time window proportional with the pulse duration • Dead time suppress pile-up on the baseline • Pile-up on the decay suppressed using Khi2 with template pulse • Correct the live time with thePoisson law : probability to have 0 pulse during the pulse decay time • Live time and signal processingdeterminationvalidatedwithsimulated data streams Pulse height (a.u.) tstart Time (s) Pulse height (a.u.) Khi2

  18. INTENSE SATELLITE STRUCTURES : EXAMPLE FOR 210Pb L3-M5 (La1) Total fit Diagram Satellite Shake-off Fluorescence Background L3-M4 (La2) 10000 L3-M1 (Ll) Pb Zn W L2-M1 (Lh) Po W L3-M2 1000 Au W L3-M3 W Counts per channel 100 10 9200 10000 10800 11600 M5 M1 L3 L2 L1 M5 M1 L3 L2 L1 Energy (eV) X-ray transition line (diagram line) E(L3-M5) = 10.839 eV X-ray satellite E’(L3M4-M4M5) > E(L3-M5) Shift up to 100 eV CosterKronig transition L3-L1M4

  19. Relative emission intensities of L X-ray from 241Am 241Am 18th Workshop on LowTemperature Detectors| Milano | 22-26/07/2019 | Matias RODRIGUES

  20. Difficulties to calculate L X-ray emission intensities from radionuclide decays The calculations require nuclear and atomic fundamental parameters (FPs): • g transition probabilities and partial ICCs  Primary vacancy distribution • Coster-Kronig transition probabilities fij Reorganized vacancy distribution • Fluorescence yields wLi Probability of radiative transitions for each subshell Li • Radiative transition rates  If the intensity of each L X-ray transitions is needed Large uncertainties or systematic errors because: • Atomic FPs fijand wLi have large uncertainties (5-50% for fij,5-20% for wLi) [J.L. Campbell, At. Data. 5 (2003) 291–315] • For anomalous g transitions ICCs cannot be calculated (i.e. 241Am, 240Pu) [V.M. Gorozhankina and M.-M. Be, Appl. Radiat. Isot 66 (2008) 722–728] • Atomic FPs calculations simplified by some assumptions (i.e. single vacancy atomic configuration) 18th Workshop on LowTemperature Detectors| Milano | 22-26/07/2019 | Matias RODRIGUES

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