Source preparation of 241Am and 129I for MMC absorbers of a multi-channel decay energy spectrometer

Abstract

In the framework of the European project PRIMA-LTD (Towards new Primary Activity. standardization methods based on Low-Temperature Detectors), new source preparation techniques adapted for low temperature detectors, in this case magnetic microcalorimeters (MMC), have been developed. Multiple pixelated ²⁴¹Am sources were produced at once using a standard method, electro-precipitation. The size and location of the deposits were controlled by masking the gold foil used for the deposition. Two types of masks were used, one made with Kapton® tape and the other one using copper tape. A new method was also developed for ¹²⁹I source by having ¹²⁹I react with silver in order to create a Ag-I layer on the absorber. Nanoporous silver disks were used to maximize the amount of ¹²⁹I deposited. The sources were characterized using autoradiography imaging to check the deposition homogeneity, a defined solid angle (DSA) detector for ²⁴¹Am activity and a HPGe gamma spectrometer for ¹²⁹I activity. Satisfactory results were achieved, validating the preparation processes.

Keywords: Am-241; Electro-precipitation; I-129; Low temperature detector; Magnetic microcalorimeter; Nanoporous silver; Source preparation.