# US 11,029,426 B2 · Detector for X-ray fluorescence

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- Number: US 11,029,426 B2
- Document ID: US11029426B2
- Status: Granted
- Kind: B2
- Application number: 16/852,781
- Filed: 2020-04-20
- Published: 2020-08-06
- Granted: 2021-06-08
- Earliest claimed: 2017-10-26
- Assignees: Shenzhen Xpectvision Technology Co., Ltd.
- Applicants: Shenzhen Xpectvision Technology Co., Ltd.
- Inventors: Peiyan Cao; Yurun Liu
- Web page: https://patentgrep.com/patent/US11029426B2

## CPC

- G01T 1/241: {Electrode arrangements, e.g. continuous or parallel strips or the like}
- G01T 1/247: {Detector read-out circuitry (for processing gain or off-set correction H04N)}
- G01N 23/223: by irradiating the sample with X-rays or gamma-rays and by measuring X-ray fluorescence
- G01T 1/16: Measuring radiation intensity (G01T1/29 takes precedence {; self-powered detectors G01T3/006; using an ionisation chamber filled with a liquid or solid, e.g. frozen liquid, dielectric G01T3/008})
- G01N 2223/507: secondary-emission detector
- G01T: MEASUREMENT OF NUCLEAR OR X-RADIATION (radiation analysis of materials, mass spectrometry G01N23/00; tubes for determining the presence, intensity, density or energy of radiation or particles H01J47/00)
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)

## 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; an X-ray absorption layer; wherein the X-ray absorption layer comprises an electrical contact within each of the pixels, and a focusing electrode surrounding the electrical contact and configured to direct to the electrical contact charge carriers generated by an X-ray photon incident within confines of the focusing electrodes; 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.

## Claims

### Claim 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, within a period of time;
an X-ray absorption layer;
wherein the X-ray absorption layer comprises an electrical contact within each of the pixels, and a focusing electrode surrounding the electrical contact and configured to direct to the electrical contact charge carriers generated by an X-ray photon incident within confines of the focusing electrodes; 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.

### Claim 2 (depends on 1)

The detector of claim 1, wherein the focusing electrode comprises polysilicon, a metal or a metal alloy.

### Claim 3 (depends on 1)

The detector of claim 1, wherein the focusing electrode is not in direct contact with the electrical contacts.

### Claim 4 (depends on 1)

The detector of claim 1, wherein the focusing electrode comprises discrete electrodes in shapes of columns or pillars.

### Claim 5 (depends on 4)

The detector of claim 4, wherein the discrete electrodes are arranged along a surface of a polyhedral or cylindrical tube or cone.

### Claim 6 (depends on 1)

The detector of claim 1, wherein the focusing electrode comprises an electrode in a shape of a polyhedral or cylindrical tube or cone.

### Claim 7 (depends on 1)

The detector of claim 1, wherein the electrical contacts are at a first surface of the X-ray absorption layer; wherein the focusing electrode extends between the first surface and a second surface of the X-ray absorption layer opposite the first surface.

### Claim 8 (depends on 1)

The detector of claim 1, wherein the focusing electrode is electrically isolated from the electrical contacts.

### Claim 9 (depends on 1)

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

### Claim 10 (depends on 1)

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

### Claim 11 (depends on 1)

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

### Claim 12 (depends on 1)

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.

### Claim 13 (depends on 1)

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

### Claim 14 (depends on 12)

The detector of claim 12, wherein the ADC is a successive-approximation-register (SAR) ADC.

### Claim 15 (depends on 1)

The detector of claim 1, further comprising:
a first voltage comparator configured to compare a voltage of the electrical 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.

### Claim 16 (depends on 15)

The detector of claim 15, further comprising a capacitor module electrically connected to the electrical contact, wherein the capacitor module is configured to collect charge carriers from the electrical contact.

### Claim 17 (depends on 15)

The detector of claim 15, wherein the controller is configured to activate the second voltage comparator at a beginning or expiration of the time delay.

### Claim 18 (depends on 15)

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

### Claim 19 (depends on 15)

The detector of claim 15, wherein a rate of change of the voltage is substantially zero at expiration of the time delay.

### Claim 20 (depends on 15)

The detector of claim 15, wherein the X-ray absorption layer comprises a diode.

### Claim 21 (depends on 15)

The detector of claim 15, wherein the X-ray absorption layer comprises silicon, germanium, GaAs, CdTe, CdZnTe, or a combination thereof.

### Claim 22 (depends on 1)

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

### Claim 23 (depends on 1)

A system comprising the detector of claim 1 and an X-ray source, wherein the system is configured to perform X-ray radiography on human chest or abdomen.