Multi-layer horizontal computed tomography (CT) detector array with at least one thin photosensor array layer disposed between at least two scintillator array layers

1. An imaging system comprising:

a radiation sensitive detector array, comprising:

a first assembly including:

a first scintillator array layer;

a first photosensor array layer optically coupled to the first scintillator array Layer; and

a first circuit electrically connected to the first photosensor array layer;

a second assembly including:

a second scintillator array layer;

a second photosensor array layer optically coupled to the second scintillator array layer; and

a second circuit electrically connected to the second photosensor array layer; and

a readout circuit affixed to the second scintillator,

wherein the first assembly and the second assembly are stacked in opposing directions, the first circuit is affixed to the second circuit, the second circuit is electrically connected to the readout integrated circuit by a first flexible connection that runs along a side of the second scintillator, and the first circuit is electrically connected to the readout integrated circuit by a second flexible electrical connection that runs along the side.

2. The imaging system of claim 1 , wherein the first photosensor array layer and the second photosensor array layer are located between the first scintillator array layer and the second scintillator array layer.

3. The imaging system of claim 1 , wherein the first photosensor array layer or the second photosensor array layer produces a first current by direct conversion that is less than one tenth of one percent of a second current produced in the first photosensor array layer or the second photosensor array layer by light from the first scintillator array layer or the second scintillator array layer.

4. The imaging system of claim 3 , wherein the first photosensor array layer and the second photosensor array layer include a material with an atomic number of less than thirty-five.

5. The imaging system of claim 3 , wherein the first photosensor array layer and the second photosensor array layer comprises at least one of silicon or gallium arsenide.

6. The imaging system of claim 5 , wherein the first photosensor array layer and the second photosensor array layer include a thinned semiconductor-on-insulator photodiode array mounted on film.

7. The imaging system of claim 5 , wherein the first photosensor array layer and the second photosensor array layer include a thin photodiode array printed on a flexible plastic sheet.

8. The imaging system of claim 1 , wherein the first scintillator array layer is nearer to incoming radiation than the second scintillator array layer, wherein the first scintillator array layer includes a first material with a first atomic number and the second scintillator array layer that is farther from the incoming radiation than the first scintillator array layer includes a second material with a second atomic number material, wherein the first atomic number is less than the second atomic number.

9. The imaging system of claim 8 , wherein the first scintillator array layer includes at least one of doped zinc selenide or doped yttrium-gadolinium aluminum garnet.

10. The imaging system of claim 8 , wherein the second scintillator array layer includes at least one of gadolinium oxysulfide or lutetium aluminum garnet.

11. The imaging system of claim 1 , wherein the first photosensor array layer and the second photosensor array layer, comprises: individual photodiodes.

12. The imaging system of claim 11 , further comprising:

second readout electronics; and

a second electrical circuit coupled to the second photosensor array layer, wherein the second electrical circuit routes electrical signals produced by a subset of the individual photodiodes to the second readout electronics.

13. A method comprising:

detecting radiation with a multi-spectral horizontal detector array of an imaging system wherein the detector array includes:

a first assembly including:

a first scintillator array layer;

a first photosensor array layer optically coupled to the first scintillator array layer; and

a first circuit electrically connected to the first photosensor array layer;

a second assembly including:

a second scintillator array layer;

a second photosensor array layer optically coupled to the second scintillator array layer; and

a second circuit electrically connected to the second photosensor array layer; and

a readout circuit affixed to the second scintillator,

wherein the first assembly and the second assembly are stacked in opposing directions, the first circuit is affixed to the second circuit, the second circuit is electrically connected to the readout integrated circuit by a first flexible connection that runs along a side of the second scintillator, and the first circuit is electrically connected to the readout integrated circuit by a second flexible electrical connection that runs along the side.

14. The method of claim 13 , wherein the first photosensor array layer and the second photosensor array layer convert less than one percent of radiation incident thereon into direct-conversion current.

15. The method of claim 14 , wherein the first photosensor array layer and the second photosensor array layer include a material with an atomic number of less than thirty-five.

16. The method of claim 13 , further comprising:

routing signals from individual photodiodes of the first photosensor array layer and the second photosensor array layer to readout electronics using flexible electrical circuits.

17. The method of claim 16 , further comprising:

routing the signals to at least two integrated circuits of the readout electronics which are arranged with respect to each other along a first direction of incoming radiation.

18. The method of claim 16 , further comprising:

routing the signals to at least two integrated circuits of the readout electronics which are arranged with respect to each other along a second direction transverse to incoming radiation.

19. The method of claim 16 , further comprising:

routing the signals to readout electronics that includes radiation hardened components.

20. The method of claim 16 , further comprising:

shielding radiation traversing the first scintillator array layer, the second scintillator array layer, the first photosensor array layer, and the second photosensor layer with a radiation shield located between the readout electronics and the radiation.

21. The method of claim 13 , further comprising:

routing signals produced by individual photodiodes of the first photosensor array layer and the second photosensor array layer from at least one edge of the first photosensor array layer and the second photosensor array layer to readout electronics using an electrical interconnect.

22. A radiation sensitive detector array, comprising:

a first assembly including:

a first scintillator array layer;

a first photosensor array layer optically coupled to the first scintillator array layer; and

a first circuit electrically connected to the first photosensor array layer;

a second assembly including:

a second scintillator array layer;

a second photosensor array layer optically coupled to the second scintillator array layer; and

a second circuit electrically connected to the second photosensor array layer; and

a readout circuit affixed to the second scintillator,

wherein the first assembly and the second assembly are stacked in opposing directions, the first circuit is affixed to the second circuit, the second circuit is electrically connected to the readout integrated circuit by a first flexible connection that runs along a side of the second scintillator, and the first circuit is electrically connected to the readout integrated circuit by a second flexible electrical connection that runs along the side.