Atelier Bilan NEEDS 910 avril 2018 The CANDELLE

Atelier Bilan NEEDS – 9/10 avril 2018 The CANDELLE experiment for characterization of neutron sensitivity of Li. F TLDs M. Le Guillou 1, A. Billebaud 2, A. Gruel 1, G. Kessedjian 2, O. Méplan 2, C. Destouches 1, P. Blaise 1 1 CEA, DEN, DER, Experimental Physics Service 2 LPSC, Université Grenoble-Alpes, CNRS/IN 2 P 3 adrien. gruel@cea. fr

THE CANDELLE PROJECT q Within the NEEDS framework, collaboration between: § CEA Cadarache – DEN/DER/SPEx/Experimental programs laboratory – In charge of measurements in EOLE and MINERVE ZPRs Needs in calibration of the response of lithium-enriched TLDs in both pure gamma and neutron fields, for measurements in mixed fields § CNRS/IN 2 P 3 – Grenoble-Alpes University – Laboratory of Subatomic Physics & Cosmology – In charge of the GENEPI-2 accelerator @ PEREN Neutrons supplier for the CANDELLE experiment 9 AVRIL 2018 Réunion bilan NEEDS 2017 LPSC Grenoble 2

OVERVIEW OF CANDELLE Context q Gamma heating measurements in RRs § Experimental validation of calculation schemes (MTRs, NPPs, …) § Nuclear data improvement for material of interest (Al, Be, Hf, …) Experimental data in ZPRs such as EOLE and MINERVE – Low flux, mixed n/g field q Experimental method based on thermo-luminescent dosimetry § Emitted light ∝ absorbed dose Material : Li. F: Mg, Ti 9 AVRIL 2018 Réunion bilan NEEDS 2017 LPSC Grenoble 3

OVERVIEW OF CANDELLE q Measurement and analysis procedure: § Calibration in a pure gamma field (60 Co source) § Irradiation in a mixed n/g field § Correction factors: TLD (Li. F) dosimeter ~ 3 -5 mm / h ~ 1 mm – Geometry and calibration calculations – Neutron response calculation and literature data Pillbox (Al, Hf, acier, etc) h ~ 10 mm ext ~ 9 mm intj ~ 5 mm Objective of the CANDELLE project Experimental assessment of the neutron contribution to total doses (n+g) for Li. F TLDs measurements in reactors 9 AVRIL 2018 Réunion bilan NEEDS 2017 LPSC Grenoble 4

OVERVIEW OF CANDELLE Determination of gamma dose and thermal neutron fluence in BNCT beams from the TLD-700 glow curve shape G. Gambarini, G. Bartesaghi, S. Agosteo, E. Vanossi, M. Carrara et M. Borroni, Radiation Measurements 45 (2010) 640– 642 9 AVRIL 2018 Réunion bilan NEEDS 2017 LPSC Grenoble 5

CANDELLE PHASE 1 (2016) TLD-600/700 washers (Al) Pillboxes (Al) GENEPI-2 9 AVRIL 2018 Réunion bilan NEEDS 2017 LPSC Grenoble 6

CANDELLE PHASE 1 (2016) Phase 1 : results q GENEPI-2 irradiation (03/2016) § 4 x TLD-600 and 4 x TLD-700 9 AVRIL 2018 TLD-600 (6 Li. F) TLD-700 (7 Li. F) Rn ~ 4. 7 ± 3% Rn ~ 5. 0 ± 13% Réunion bilan NEEDS 2017 LPSC Grenoble 7

CANDELLE PHASE 1 (2016) q EOLE irradiations (11/2015 and 03/2016) § Mixed n/g field § PWR-type neutron flux shape, ~ 107 n. cm-2. s-1. W-1 § TLD-700, 10 W during 10 min (TLD-600 led to the saturation of the reader) Stainless steel baffle Core TLD Water 9 AVRIL 2018 Réunion bilan NEEDS 2017 LPSC Grenoble 8

CANDELLE PHASE 1 (2016) q EOLE irradiations (11/2015 and 03/2016) Location Center core Core periphery Water Total dose (m. Gy) 1191 ± 23 642 ± 10 169 ± 3 Neutron contribution 9. 0% 8. 7% 11. 9% Relative uncertainty (1σ) 5. 2% 5. 1% Relative discrepancy 10. 0% 6. 5% 4. 9% TLD-700 (7 Li. F) R ~ 27 ± 5% 9 AVRIL 2018 Réunion bilan NEEDS 2017 LPSC Grenoble 9

CANDELLE PHASE 1 (2016) q Feasibility demonstrated q Results to be compared to the commonly used method q …and also to calculations q But: § GENEPI measurements with a fast neutron spectrum § Quite low statistics… § Low precision on 6 -7 Li enrichment… 9 AVRIL 2018 Réunion bilan NEEDS 2017 LPSC Grenoble 10

CANDELLE PHASE 2 (2017 - …) Phase 2: outlooks q Increase of the neutron intensity of the GENEPI q Measurements in a thermalized « pure » neutron field § Screens in between target and pillboxes – Thickness? Material? – Keep g/n ratio as low as possible § Spectrum characterization Preliminary calculations 9 AVRIL 2018 To be extended to other materials (H 2 O, BN, …) Réunion bilan NEEDS 2017 LPSC Grenoble 11

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