Revised_Specifications.pdf

SPECIFICATIONS

Time-Resolved, Single-Photon Imaging Detector

BACKGROUND:

In support of the National Institute of Standards and Technology (NIST) mission to develop quantum information science, the Ion Trapping Group of the Time and Frequency Division is carrying out a series of experiments employing trapped ion crystals as registers for storing quantum information. This work requires sensitive imaging detectors for measuring weak, laser-induced ion fluorescence.

PURPOSE:

This purchase is for an imaging, photon-counting detector for measuring the weak, laser-induced fluorescence from a trapped ion crystal. The detector will enable the detection of individual ions within the crystal. Because the ion crystal undergoes a periodic rotation, we require a detector that provides a time coordinate t in addition to the x, y coordinate of each detected photon.

DELIVERABLES:

A time-resolved, single-photon imaging detector, including all the electronics and software required to operate and readout the detector, and transfer the output to a high-performance PC.

TECHNICAL SPECIFICATIONS:

The detector shall meet the following technical specifications:

1. Detector format: The format or size of the photocathode can be as large as 40 mm diameter.

2. Quantum efficiency: The photocathode should have high quantum efficiency (QE) in the blue to near UV. In particular, QE > 20% at 313 nm and at 280 nm.

3. Dark count rate: < 200 cps/cm2 at room temperature; no bright spots (defined as an area less than 300 microns in diameter) with intensity > 1 cps

4. Image uniformity: QE variation < 40 %; no dead spots with a dimension >300 𝜇𝜇m.

5. The detector tube should be mounted in a housing that provides for straight forward electrical connections (both high voltage and signal), and a means of mounting the detector housing for use in experiments.

6. Position resolution: Within the inner 90% of the photocathode diameter, the image of a pinhole obtained with diffuse light at 313 nm or 280 nm should be less than 0.1 mm FWHM for global count rates < 200 kHz. This provides greater than 400 pixels across a 40 mm diameter photocathode. For global count rates > 200 kHz and < 1 MHz, the position resolution should be

0.2 mm FWHM or less.

7. Image non-linearity: Non-linearity is the deviation in the image of an array of regularly spaced pin holes from linearity. Within the inner 90% of the photocathode diameter, the non-linearity should be less than 0.5% of the photocathode diameter (i.e. 0.2 mm for a 40 mm diameter photocathode) after application of a fixed (or pre-calibrated) correction function. A means of calibrating inherent spatial non-linearities of the anode is very desirable, for example, through the use of a hexanode.

8. Timing resolution: Each detected photon shall be time-stamped with a resolution of < 1 ns. The system should have the capability of time stamping relative to an external periodic trigger. For our application we will employ a periodic trigger with a rate higher than 10 kHz and less than 1 MHz.

9. Count rate/ dead time: The detector and electronics must be able to process a 1 MHz global rate of randomly spaced (in x, y and t) events (that is, detected photons). Specifically, the system should not be dead to (or lose) more than 5% of the events that generate an electron cloud on the anode.

10. Software: Software is required to operate and read out the detector, and transfer the output to a high-performance PC for further processing. We desire to use a PC with a Windows 7 or later operating system. Desirable features of the software include a “movie mode” that does not employ time stamping but rather continuously displays images with a preset integration time.

In addition, we require a list mode where 1 MHz (and higher) data rates of (x, y, t) data are continuously transferred to disk.

TECHNICAL CONSIDERATIONS:

The ability of the detector and electronics to process a 1 MHz (or greater) global rate of randomly spaced events is a key requirement for planned NIST work. In addition to this being one of the most important specifications, it may also be the most difficult specification to satisfy. The ability to process count rates greater than 1 MHz increases the utility of the single photon detector for NIST work.

In addition, the position resolution and image non-linearity specifications are important for planned NIST work of detecting individual ions in a rotating trapped-ion crystal. The ability to analyze and calibrate non-linearities of the detector increases the utility of the detector for NIST work.

KEY AREAS OF IMPORTANCE:

A key requirement for the detector and electronics is that it process a 1 MHz global rate of randomly spaced (in x, y and t) events. Specifically, at a 1 MHz global count rate, the system should not lose more than 5% of the events that generate an electron cloud on the anode.

In addition to the count rate processing capability, the position resolution and image non-linearity specifications are important areas of performance for NIST work.

GOVERNMENT FURNISHED PROPERTY OR INFORMATION: NIST will provide a high- performance PC to run the software and interface with the detector hardware. NIST preference is for the PC to use a Windows 7 or later operating system.

DELIVERABLE SCHEDULE:

Delivery shall be no later than 26 weeks after receipt of order.

INSPECTION AND ACCEPTANCE:

End user will have 30 days to inspect and test the merchandise upon delivery. The merchandise should perform according to specifications.

ATTACHMENTS/REFERENCES: Identify, if needed: File name of Drawings, Definition of Terms, etc.