Variable Energy X-ray Fluorescence Source

TL;DR

This paper presents a design for a variable energy X-ray fluorescence source using a low-activity technetium-99 beta source, capable of producing tunable X-ray energies for detector response studies.

Contribution

It introduces a novel, rotatable X-ray fluorescence source with adjustable energy levels, suitable for low-energy detector response research in vacuum and cryogenic conditions.

Findings

Produces X-rays between 4 and 70 keV at ~1 Hz

Non-detectable radiation when in storage position

Compatible with vacuum and liquid nitrogen temperatures

Abstract

We detail the design of a variable energy, x-ray fluorescence source using a low activity (1.8$\times10^6$~dpm) \nuc{99}{Tc} $\beta$ source that irradiates thin foils. By rotating the source among foils of Ti, Zn, Nb, Ag, and Au, the device produces x rays between 4 and 70 keV at a rate near 1 Hz. When the source is placed in a storage position, the external radiation is non-detectable. The design of the shielding and rotation mechanism permits use in vacuum and at liquid nitrogen temperature. The design is intended for the study of the low energy response to radiation impinging upon Ge detector surfaces. The source will be useful for understanding the detector response in large-scale Ge arrays such as \textsc{Majorana} and LEGEND.