X-ray signal processor and x-ray spectrometer

Patent metadata

Field	Value
Publication number	US-10996349-B2
Application number	US-201916697200-A
Country	US
Kind code	B2
Filing date	Nov 27, 2019
Priority date	Nov 27, 2018
Publication date	May 4, 2021
Grant date	May 4, 2021

Abstract

Provided is an X-ray signal processor and an X-ray spectrometer that are configured to measure X-rays and, at the same time, accurately detect, with a simple method, the degree of performance degradation of a semiconductor detector. The X-ray signal processor includes: a semiconductor detector configured to generate a charge corresponding to energy of detected X-rays; a preamplifier configured to output a ramp voltage signal corresponding to the generated charge; a counter configured to count the X-rays for each voltage change amount due to the charge based on the ramp voltage signal; and a judgment part configured to determine whether the semiconductor detector has been degraded based on a first voltage change evaluation value corresponding to a total sum of products of the voltage change amount and an occurrence frequency thereof, and a second voltage change evaluation value corresponding to an increase amount of the ramp voltage signal.

First claim

What is claimed is:

1. An X-ray signal processor, comprising:
a semiconductor detector configured to generate a charge corresponding to energy of detected X-rays;
a preamplifier configured to output a ramp voltage signal corresponding to the generated charge;
a counter configured to count the X-rays for each voltage change amount due to the charge based on the ramp voltage signal; and
a judgment part configured to determine whether the semiconductor detector has been degraded based on a first voltage change evaluation value corresponding to a total sum of products of the voltage change amount and an occurrence frequency thereof, and a second voltage change evaluation value corresponding to an increase amount of the ramp voltage signal.

2. The X-ray signal processor according to claim 1 , wherein the first voltage change evaluation value includes a value obtained by dividing an amplitude of the ramp voltage signal by a sum of the total sum and a value of a leakage current flowing through the semiconductor detector in a normal state.

3. The X-ray signal processor according to claim 1 ,
wherein each cycle of the ramp voltage signal includes:
a reset period lasting from after the ramp voltage signal reaches an upper limit value until the ramp voltage signal is reduced to a lower limit value; and
a detection period other than the reset period, and

wherein the second voltage change evaluation value includes a value corresponding to one of a slope and the increase amount of the ramp voltage signal in the detection period.

4. The X-ray signal processor according to claim 3 , further comprising a cycle measuring part configured to measure a cycle of the ramp voltage signal,
wherein the second voltage change evaluation value includes the cycle of the ramp voltage signal measured by the cycle measuring part, and
wherein the judgment part is configured to determine whether the semiconductor detector has been degraded based on a first threshold value set in advance and one of a difference or a ratio between the first voltage change evaluation value and the second voltage change evaluation value.

5. The X-ray signal processor according to claim 4 , wherein the judgment part is configured to determine whether to perform the determination based on the total sum and a second threshold value set in advance.

6. The X-ray signal processor according to claim 4 , further comprising:
a storage part configured to continuously store one of the difference or the ratio between the first voltage change evaluation value and the second voltage change evaluation value; and
a prediction part configured to predict a time at which the semiconductor detector will be degraded from a transition of the stored one of the difference or the ratio.

7. The X-ray signal processor according to claim 1 , further comprising a cycle measuring part configured to measure a cycle of the ramp voltage signal,
wherein the first voltage change evaluation value includes the total sum,
wherein the second voltage change evaluation value includes the cycle of the ramp voltage signal measured by the cycle measuring part, and
wherein the judgment part is configured to determine whether the semiconductor detector has been degraded based on a value obtained by subtracting the first voltage change evaluation value from a value obtained by dividing an amplitude of the ramp voltage signal by the second voltage change evaluation value.

8. An X-ray spectrometer, comprising:
a semiconductor detector configured to detect X-rays emitted by irradiating a sample with exciting lines, to thereby generate a charge corresponding to energy of the X-rays;
a preamplifier configured to output a ramp voltage signal corresponding to the generated charge;
a counter configured to count the X-rays for each voltage change amount due to the charge based on the ramp voltage signal;
a judgment part configured to determine whether the semiconductor detector has been degraded based on a first voltage change evaluation value corresponding to a total sum of products of the voltage change amount and an occurrence frequency thereof, and a second voltage change evaluation value corresponding to an increase amount of the ramp voltage signal; and
an analyzer configured to analyze elements in the sample based on the counted X-rays.

Assignees

• Rigaku Denki Co Ltd

Inventors

• Tada Tsutomu

Classifications

• G01T1/244 Primary

  Auxiliary details, e.g. casings, cooling, damping or insulation against damage by, e.g. heat, pressure or the like · CPC title

• G01T1/366 Primary

  with semi-conductor detectors · CPC title

• A61B6/4208

  characterised by using a particular type of detector · CPC title

• A61B6/585

  Calibration of detector units · CPC title

• G01T1/247

  Detector read-out circuitry (for processing gain or off-set correction H04N) · CPC title