Multiple energy detector
View Patent ↗The present specification describes an improved multi-energy radiation detector. In one embodiment, the signal generated by the detection medium is converted to digital form directly at the point of signal collection. This avoids the need for power intensive high bandwidth amplifiers and analog-to-digital converters, as it integrates the sensing device and signal processing onto the same silicon substrate to reduce the number of components in the system. In one embodiment, a single photon avalanche diode (SPAD) is coupled directly to a threshold detector to achieve an intrinsically low power and low noise detector.
1. A multi-energy detector for detecting incident radiation, comprising:
a scintillator material adapted to convert the incident radiation into a plurality of optical photons;
an array of pixel circuits, wherein each pixel circuit comprises a photon avalanche diode (SPAD) coupled to and in electrical communication with a threshold detector, wherein each SPAD is optically coupled to the scintillator material and adapted to generate a current in response to detecting one or more optical photons, and wherein the threshold detector is configured to generate a digital pulse in response to said current;
processing electronics for processing the digital pulse from each pixel circuit in said array of pixel circuits and converting said digital pulse into an energy profile of the incident radiation; and
a clock configured to generate a variable frequency and configured to be in electrical communication with the array of pixel circuits and the processing electronics, wherein a gain of the multi-energy detector is adapted to vary based on the variable frequency.
2. The multi-energy detector of claim 1 , wherein each of said pixel circuits further comprises an active quench circuit, wherein the active quench circuit is configured to reset said SPAD.
3. The multi-energy detector of claim 1 , wherein the scintillator material is LYSO crystal.
4. The multi-energy detector of claim 1 , wherein said array of pixel circuits and said processing electronics are fabricated on a single CMOS substrate.
5. The multi-energy detector of claim 1 , wherein said processing electronics includes an accumulator configured to generate a pixel count wherein said pixel count is transmitted to a latching register.
6. The multi-energy detector of claim 5 wherein said latching register is configured to receive said pixel count from said accumulator, store said pixel count, and send said pixel count to a digital buffer.
7. The multi-energy detector of claim 6 wherein said digital buffer is configured to receive said pixel count from said latching register, buffer said pixel count, and send said buffered pixel count to a digital pulse processor.
8. The multi-energy detector of claim 7 wherein said digital pulse processor is configured to receive said buffered pixel count from said digital buffer, find a specific energy value, and send said energy value to a range shifter.
9. The multi-energy detector of claim 8 wherein said range shifter is configured to receive said energy value from said digital pulse processor, scale said energy value, and send said scaled energy value to a histogrammer.
10. The multi-energy detector of claim 9 wherein said histogrammer is configured to receive said scaled energy value from said range shifter, generate a histogram of said scaled energy value to create energy spectrum data, and send said energy spectrum data to a serializer.
11. The multi-energy detector of claim 10 wherein said serializer is configured to receive said energy spectrum data from said histogrammer and pass said energy spectrum data to an external device for signal analysis and image display.
12. The multi-energy detector of claim 8 , wherein the digital pulse processor is configured to find a specific energy value by searching time sequence data to find an X-ray pulse and its associated pulse height, wherein the pulse height represents a corresponding energy level.
13. The multi-energy detector of claims 1 , wherein the frequency of the clock is in the range of 100 MHz to 500 MHz.