An optimized online filter stack spectrometer

TL;DR

This paper presents an online filter stack spectrometer for laser-plasma X-ray spectrum measurement, optimized using genetic algorithms, calibrated with gamma-ray sources, and capable of 1 kHz real-time spectrum determination.

Contribution

It introduces a novel optimized design of a wideband online filter stack spectrometer using genetic algorithms for sensor and filter arrangement, with a practical 15-channel prototype.

Findings

Significantly reduced unfolding error through optimization.

Successful calibration with gamma-ray sources.

Prototype achieves 1 kHz real-time spectrum measurement.

Abstract

The spectrum of laser-plasma-generated X-rays is very important as it can characterize electron dynamics and also be useful for applications, and nowadays with the forthcoming high-repetition-rate laser-plasma experiments, there is a raising demand for online diagnosis for the X-ray spectrum. In this paper, scintillators and silicon PIN diodes are used to build a wideband online filter stack spectrometer. The genetic algorithm is used to optimize the arrangements of the X-ray sensors and filters by minimizing the condition number of the response matrix, thus the unfolding error can be significantly decreased according to the numerical experiments. The detector responses are quantitatively calibrated by irradiating the scintillator and PIN diode using different nuclides and comparing the measured gamma-ray peaks. Finally, a 15-channel spectrometer prototype has been implemented. The X-ray detector, front-end electronics, and back-end electronics are integrated into the prototype, and the prototype can determine the spectrum with 1 kHz repetition rates.