Bücherl, T.

Ehrenberg, H.

Mühlbauer, M.J.

Senyshyn, A.

Söllradl, S.

Wagner, F.M.

English

Mühlbauer, M. J.

Wagner, F. M.

KITopen

KIT – University of the State of Baden-Wuerttemberg and National Research Center of the Helmholtz Association 1 m20 MW HFR[1] A Thermal Neutron Beam Option for NECTAR at FRM II  M.J. Mühlbauer1,2, T. Bücherl2,3, A. Senyshyn2, S. Söllradl2, F.M. Wagner2, H.Ehrenberg1,4 Motivation  Combination of thermal and fast neutrons at a single instrument  Thermal beam accessible by simply removing the uranium    converter via remote control  Only slight modifications of the existing instrumentation; main    components like shielding, shutter system, access control and    sample positioning do not need to be changed or adapted    Pure thermal beam extends the neutron energy spectra    available for neutron imaging at FRM II 1Institute for Applied Materials (IAM), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany 2Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, Lichtenbergstr. 1, 85748 Garching, Germany 3Technische Universität München, ZTWB Radiochemie München RCM, Walther-Meissner-Str. 3, 85748 Garching, Germany 4Helmholtz-Institute Ulm for Electrochemical Energy Storage (HIU), P.O. Box 3640, D-76021 Karlsruhe, Germany Contact: Dr. M.J. Mühlbauer e-mail: martin.muehlbauer@kit.edu unfiltered Median 3 Median 5 Median 7 Median 9 Median 9 normalized Prove of concept  Installation of an aperture, 25 mm in diameter, at the    neutron beam window in front of the filter bench (Fig.1)  Evacuated flight tube mounted temporarily inside the    irradiation room (Fig. 2)   DELCam [2] used as a preliminary detector for thermal    neutrons, small rotation stage for tomography (Fig. 3)  estimated parameters:  neutron flux 107 n s-1 cm-2  L/D ratio 240  beam size 85 mm The thermal neutron beam option does fulfill the requirements of a state of the art neutron imaging facility [3]. A removable flight tube has to be constructed for the irradiation room.  Operational and storage state of the removable flight tube (1) (2) (3) Flight tube Aperture Detector References:  [1] T. Bücherl et al., NIM  A 651 (2011) 86-89.  [2] M.J. Mühlbauer et al., NIM  A 542 (2005) 324-328.  [3] E.H. Lehmann et al., NIM  A 615 (2011) 1-5. Future applications  “Dual Energy” experiments combining thermal    and fast data, e.g. hydrogen storage materials  Irradiation and activation of samples  Neutron imaging using a pure thermal beam,    e.g. investigation of lithium-ion batteries  Detector development making use of the two    quite different neutron energy spectra Preliminary results  The spatial resolution could be determined by a    Cd edge to be 88.2 µm (5.66 lp/mm); at a distance    of 28 cm still 569 µm (0.88 lp/mm) were reached.  Gamma spots are efficiently removed by filtering a    series of 3 to 5 images (here for a M5 screw).  For samples with higher neutron absorption a pure    thermal beam helps to reduce beam hardening    effects and cell activation compared to a cold    neutron beam, e.g. for lithium-ion batteries.   Tomography data sets acquired at ANTARES    (cold/thermal), NECTAR (thermal) and SPODI    (monochromatic, l=1.548 Å) have been compared,    where a thermal spectrum seems to be a good    compromise between neutron statistics and beam    hardening effects.  at 28 cm in contact M5 screw Cd edge 18650-type Li-ion cell 

A thermal neutron beam option for NECTAR at FRM II

https://publikationen.bibliothek.kit.edu/220097897/3816679

A thermal neutron beam option for NECTAR at FRM II

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