# 18th International Workshop on Low Temperature Detectors (LTD-18)

22-26 July 2019
Milano
Europe/Rome timezone

## Multi-isotope Experimental Validation of Calorimetric Electron Capture Spectral Theory

25 Jul 2019, 17:45
1h 15m
Piazza Città di Lombardia (Milano)

### Piazza Città di Lombardia

#### Milano

Piazza Città di Lombardia, 1, 20124 Milano MI
Poster Low Temperature Detector Applications

### Speaker

Dr Katrina Koehler (Los Alamos National Laboratory)

### Description

Using microcalorimeters, a high statistics, high resolution calorimetric spectrum of electron capture in ${}^{163}$Ho can be used to determine the neutrino mass. The spectral shape can be calculated from first principles with various assumptions and approximations. To determine the validity of these choices, the theoretical calculations must be compared to data from multiple isotopes. New calorimetric data for a ${}^{193}$Pt-in-Pt absorber measured with a transition edge sensor (TES) are presented and compared to theoretical calculations. In order to create this ${}^{193}$Pt-in-Pt absorber, a ${}^{192}$Pt-enriched Pt foil was irradiated at a nuclear reactor to produce ${}^{193}$Pt in situ. A small piece of this foil was cut off from the bulk foil and attached to an absorber pad thermally coupled to a TES. In this absorber, the radioactive isotope of interest has no elemental interfaces with the absorber material since both absorber and source are Pt, it is uniformly distributed throughout the absorber, and the absorber material is a pure metal. Data from this absorber is useful for understanding the electron capture theoretical shape without the complications of embedding ${}^{163}$Ho in a Au absorber matrix. Calorimetric data from the literature for ${}^{55}$Fe and ${}^{163}$Ho are also compared to theoretical calculations.

Student (Ph.D., M.Sc. or B.Sc.) N Y

### Primary author

Dr Katrina Koehler (Los Alamos National Laboratory)

### Co-authors

Mr Mark Croce (Los Alamos National Laboratory) Dr Christopher Fontes (Los Alamos National Laboratory) Dr Michael Rabin (Los Alamos National Laboratory) Dr Daniel Schmidt (National Institute of Standards and Technology) Dr Joel Ullom (National Institute of Standards and Technology)

### Presentation Materials

 Koehler_LTD-18_Pt193_Poster.pdf Koehler_LTD2019_PosterPromo.pdf