Detachable 3-layers Au absorber microfabrication for low-temperature detectors

Jawad Hadid (1) , Matias Rodrigues (2) , Abdelmounaim Harouri (1) , Christophe Dupuis (1) , David Bouville (1) , Antoine Martin (1) , Martin Loidl (2) , Laurence Ferlazzo (1)

1 C2N - Centre de Nanosciences et de Nanotechnologies
2 LNHB (CEA, LIST) - Laboratoire National Henri Becquerel (CEA, LIST)

Low temperature detectors (LTDs) used for decay energy spectrometry (DES) can provide accurate and reliable decay data thanks to their high-energy resolution and a near 100% detection efficiency for the radiations of interest. However, it is essential to consider the source quality to mitigate spectral distortion due to the self-absorption of particle energy in the source deposited. This work aimed to produce a replaceable 4π 3-layer gold absorber for DES in reusable metallic magnetic calorimeters, a class of LTDs. We present a novel 3-layer microfabrication process for a 1 mm diameter absorber with a total gold thickness ranging from 20 μm to 120 μm depending on the measured radionuclide ($^{55]$Fe or $^{241}$Am). The absorber integrates a gold nanofoam in which the radionuclide is deposited by nanodrop deposition of a few tenths of μL of a radioactive solution. We fabricated a high quality gold nanofoam layer with controllable porosity through a dealloying process using wet etching and integrating it on a thick electrodeposited gold layer. The fine study of the nanofoam microfabrication is performed using high-resolution scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDX).

Mots clés: instrumentation; nuclear instrumentation; detector; decay data measurement; spectrometry; radioactivity; ionizing radiation; metallic magnetic calorimeter; calorimeter; gold nanofoam; metrology

Domaines: Micro et nanotechnologies/Microélectronique; Instrumentations et Détecteurs [physics.ins-det]

Jawad Hadid, Matias Rodrigues, Abdelmounaim Harouri, Christophe Dupuis, David Bouville, et al.. Detachable 3-layers Au absorber microfabrication for low-temperature detectors. Micro and Nano Engineering, 2023, 20, pp.100220. ⟨10.1016/j.mne.2023.100220⟩. ⟨cea-04254532⟩