Detector for X-ray fluorescence

Patent metadata

Field	Value
Publication number	US-10539691-B2
Application number	US-201515309036-A
Country	US
Kind code	B2
Filing date	Jun 10, 2015
Priority date	Jun 10, 2015
Publication date	Jan 21, 2020
Grant date	Jan 21, 2020

Abstract

Disclosed herein is a detector, comprising: a plurality of pixels, each pixel configured to count numbers of X-ray photons incident thereon whose energy falls in a plurality of bins, within a period of time; and wherein the detector is configured to add the numbers of X-ray photons for the bins of the same energy range counted by all the pixels. Each of the pixels may comprise an analog-to-digital converter (ADC) configured to digitize an analog signal representing the energy of an incident X-ray photon into a digital signal. The pixels may be able to operate in parallel. Each of the pixels may be able to measure its dark current, such as before or concurrently with each X-ray photon incident thereon.

First claim

What is claimed is:

1. A detector, comprising:
a plurality of pixels, each pixel configured to count numbers of X-ray photons incident thereon whose energy falls in a plurality of bins of different energy ranges respectively, within a period of time; and
wherein the detector is configured to sum the numbers counted by all the pixels from only the bins of the same energy range.

2. The detector of claim 1 , further configured to compile the added numbers as a spectrum of the X-ray photons incident on the detector.

3. The detector of claim 1 , wherein the plurality of pixels are arranged in an array.

4. The detector of claim 1 , wherein the pixels are configured to count the numbers of X-ray photons within a same period of time.

5. The detector of claim 1 , wherein each of the pixels comprises an analog-to-digital converter (ADC) configured to digitize an analog signal representing the energy of an incident X-ray photon into a digital signal.

6. The detector of claim 5 , wherein the ADC is a successive-approximation-register (SAR) ADC.

7. The detector of claim 1 , wherein the pixels are configured to operate in parallel.

8. The detector of claim 1 , wherein each of the pixels is configured to measure its dark current.

9. The detector of claim 8 , wherein each of the pixels is configured to measure its dark current before or concurrently with each X-ray photon incident thereon.

10. The detector of claim 8 , wherein each of the pixels is configured to deduct a contribution of the dark current from the energy of an X-ray photon incident thereon.

11. The detector of claim 8 , wherein each of the pixels is configured to measure its dark current by measuring a time it takes for a voltage to increase by a threshold.

12. The detector of claim 1 , further comprising:
an X-ray absorption layer comprising an electric contact;
a first voltage comparator configured to compare a voltage of the electric contact to a first threshold;
a second voltage comparator configured to compare the voltage to a second threshold;
a controller;
a plurality of counters each associated with a bin and configured to register a number of X-ray photons absorbed by one of the pixels wherein the energy of the X-ray photons falls in the bin;
wherein the controller is configured to start a time delay from a time at which the first voltage comparator determines that an absolute value of the voltage equals or exceeds an absolute value of the first threshold;
wherein the controller is configured to determine whether an energy of an X-ray photon falls into the bin;
wherein the controller is configured to cause the number registered by the counter associated with the bin to increase by one.

13. The detector of claim 12 , further comprising a capacitor module electrically connected to the electric contact, wherein the capacitor module is configured to collect charge carriers from the electric contact.

14. The detector of claim 12 , wherein the controller is configured to activate the second voltage comparator at a beginning or expiration of the time delay.

15. The detector of claim 12 , wherein the controller is configured to connect the electric contact to an electrical ground.

16. The detector of claim 12 , wherein a rate of change of the voltage is substantially zero at expiration of the time delay.

17. The detector of claim 12 , wherein the X-ray absorption layer comprises a diode.

18. The detector of claim 12 , wherein the X-ray absorption layer comprises silicon, germanium, GaAs, CdTe, CdZnTe, or a combination thereof.

19. The detector of claim 1 , wherein the apparatus does not comprise a scintillator.

20. A method for measuring an energy spectrum of X-ray, comprising:
exposing a detector with a plurality of pixels to X-ray;
determining a number of X-ray photons for each of the pixels for one bin of a plurality of bins of different energy ranges respectively, wherein energy of the X-ray photon falls in the one bin;
summing the numbers determined for all the pixels from only the bins of the same energy range.

21. The method of claim 20 , wherein determining the number comprises subtracting a contribution of dark current in the each pixel.

22. The method of claim 20 , wherein determining the number comprises analog-to-digital conversion.

Assignees

• Shenzhen Xpectvision Tech Co Ltd

Inventors

• Cao Peiyan
• Liu Yurun

Classifications

• G01T1/247 Primary

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

• G01N2223/076

  X-ray fluorescence · CPC title

• G01N2223/501

  array · CPC title

• H01L27/14636

  Electricity · mapped topic

• H01L27/14661

  Electricity · mapped topic