Dual mode pixel array detector

1. A pixel array detector comprising:

a plurality of dual-mode pixels arranged in an array, each dual-mode pixel comprising:

a mixed-mode sensor configured to detect accumulated charge created by electromagnetic radiation incident on the pixel;

a digital-mode sensor configured to count individual photons incident on the pixel;

a switch configured to selectively couple the mixed-mode sensor and the digital sensor with a diode associated with the pixel;

a multiplexer configured to combine outputs from both the digital-mode sensor and the mixed-sensor path; and

a combined counter configured to receive output from the multiplexer; and

a controller configured to configure each pixel of the plurality of dual-mode pixels into either the mixed-mode or the digital-mode.

2. The pixel array detector of claim 1 , wherein the digital-mode sensor comprises a charge-sensitive amplifier, a shaper, and a comparator.

3. The pixel array detector of claim 1 , wherein the mixed-mode sensor comprises a capacitor, a slow amplifier, a comparator, and a precision charge remover.

4. The pixel array detector of claim 1 , wherein the combined counter is configured to store a photon count when the pixel is configured in the digital mode.

5. The pixel array detector of claim 1 , wherein the combined counter is configured to store a ramp count when the pixel is configured in the mixed mode.

6. The pixel array detector of claim 1 , wherein the combined counter comprises an N-bit counter, where N can have any positive integer value.

7. A method of configuring a dual-mode pixel array detector, the detector comprising a plurality of dual-mode pixels each comprising a mixed-mode sensor configured to detect accumulated charge created by electromagnetic radiation incident on the pixel, a digital-mode sensor configured to count individual photons incident on the pixel, a switch configured to selectively couple the mixed-mode sensor and the digital sensor with a diode associated with the pixel, a multiplexer configured to combine outputs from both the digital-mode sensor and the mixed-sensor path, and a combined counter configured to receive output from the multiplexer, and capable of being configured into either a mixed-mode or a digital-mode, the method comprising:

accumulating a setup image, using a data collection sample, wherein each pixel in the array is set to be in either mode comprising one of the mixed-mode or the digital-mode;

reading the setup image;

determining an intensity distribution of the setup image; and

configuring the detector such that each pixel in the array is configured into one of the mixed-mode or the digital-mode based on the intensity distribution of the setup image.

8. The method of claim 7 , wherein accumulating the setup image comprises configuring each pixel in the array into the mixed-mode.

9. The method of claim 7 , wherein accumulating the setup image comprises configuring each pixel in the array into the digital-mode.

10. The method of claim 7 , wherein accumulating the setup image comprises illuminating a crystal with X-rays.

11. The method of claim 7 , wherein determining the intensity distribution comprises determining a closed curve.

12. The method of claim 11 , further comprising configuring each pixel in the array, into one of the mixed-mode or the digital-mode, based on whether the pixel is inside or outside the closed curve.

13. The method of claim 7 , further comprising determining a threshold value for at least one of: pixel intensity, dead-time loss, and signal noise.

14. The method of claim 13 , wherein configuring the detector comprises configuring each pixel in the array, into one of the mixed-mode or the digital-mode, based on whether a measured intensity at the pixel is above or below the threshold value.

15. The method of claim 13 , further comprising determining the threshold value based on a predicated amount of dead-time loss that would result from saturation of a digital-mode pixel.

16. The method of claim 13 , further comprising determining the threshold value based on a predicated amount of signal noise that would result in under-exposure of a mixed-mode pixel.