Cryogenic detector device
View Patent ↗A cryogenic detector device includes a sensor based on a low-temperature effect and measures the temperature increase produced by the introduction of energy, such as an X-ray quantum. The smaller the thermal capacity of the sensor, the greater the temperature increase resulting from the introduction of energy and the higher the energy resolution of the sensor. Because the thermal capacity is temperature dependent, the sensor is operated in the range of comparatively small thermal capacities, i.e., in a range between 50 and 400 mK. Contrary to conventional assumptions, it was found that by keeping the three-dimensional size of the individual sensors sufficiently small and by increasing the effective sensor area, acceptable measurement results were achieved even at higher operating temperatures of the sensors in a range between 2.4 and 4.2 degrees Kelvin.
1. A detector system, comprising:
an individual sensor based on a low-temperature effect that outputs measurement signals, wherein the individual sensor includes an active sensor area;
a mechanical cooler that is thermally coupled to the individual sensor and produces a minimum cooling temperature T minK ;
a pre-amplifier connected to the individual sensor, wherein the pre-amplifier amplifies the measurement signals; and
sensor area enlargement means for producing an effective sensor area that is larger than the active sensor area of the individual sensor, wherein the detector system has an operating temperature, and wherein the operating temperature of the detector system is stabilized slightly above the minimum cooling temperature T minK .
2. The detector system of claim 1 , wherein the individual sensor has a three-dimensional size that is small enough to enable an operating temperature range of the detector system between 2.4 and 4.2 K.
3. The detector system of claim 2 , wherein the three-dimensional size of the individual sensor enables an operating temperature range of the detector system between 2.6 and 2.9 K.
4. The detector system of claim 1 , wherein the active sensor area is less than 50,000 μm 2 .
5. The detector system of claim 1 , wherein the sensor area enlargement means is an X-ray lens.
6. The detector system of claim 1 , wherein the sensor area enlargement means is a sensor matrix of a plurality of individual sensors, and wherein the individual sensor is one of the plurality of individual sensors.
7. The detector system of claim 1 , wherein the detector system includes a single one-stage mechanical cooler.
8. The detector system of claim 1 , wherein the mechanical cooler is a pulse-tube cooler.
9. The detector system of claim 1 , wherein the mechanical cooler is a Gifford-McMahon cooler.
10. The detector system of claim 1 , wherein the individual sensor is taken from the group consisting of: a superconducting tunnel diode, a magnetic calorimeter, a resistance thermometer, and a phase transition thermometer.
11. The detector system of claim 1 , wherein the individual sensor has an operating temperature, and wherein the operating temperature of the individual sensor is stabilized by a temperature compensator.
12. The detector system of claim 11 , wherein the temperature compensator allows limited thermal coupling between the mechanical cooler and the individual sensor.
13. The detector system of claim 1 , wherein the minimum cooling temperature T minK fluctuates, and wherein the temperature compensator reduces the fluctuations of the minimum cooling temperature T minK to stabilize the operating temperature to within a range of +/−1 mK.
14. The detector system of claim 1 , wherein the individual sensor and the pre-amplifier are part of a single integrated circuit.
15. The detector system of claim 1 , wherein the pre-amplifier is a Superconducting QUantum Interference Device (SQUID).
16. The detector system of claim 1 , wherein the individual sensor is held at a first temperature and the pre-amplifier is held at a second temperature, and wherein the first temperature equals the second temperature.
17. A detector system, comprising:
an individual sensor based on a low-temperature effect that outputs measurement signals, wherein the individual sensor includes an active sensor area;
a mechanical cooler that is thermally coupled to the individual sensor and produces a minimum cooling temperature T minK ;
a pre-amplifier connected to the individual sensor, wherein the pre-amplifier amplifies the measurement signals; and
sensor area enlargement means for producing an effective sensor area that is larger than the active sensor area of the individual sensor, wherein the individual sensor is held at a first temperature and the pre-amplifier is held at a second temperature, and wherein the first temperature equals the second temperature.
18. A detector system, comprising:
an individual sensor based on a low-temperature effect that outputs measurement signals, wherein the individual sensor includes an active sensor area, wherein the individual sensor has an operating temperature, and wherein the operating temperature of the individual sensor is stabilized by a temperature compenHohner;
a mechanical cooler that is thermally coupled to the individual sensor and produces a minimum cooling temperature T minK ;
a pre-amplifier connected to the individual sensor, wherein the pre-amplifier amplifies the measurement signals; and
sensor area enlargement means for producing an effective sensor area that is larger than the active sensor area of the individual sensor, wherein the minimum cooling temperature T minK fluctuates, and wherein the temperature compenHohner reduces the fluctuations of the minimum cooling temperature T minK to stabilize the operating temperature of the individual sensor to within a range of +/−100 mK.
19. A detector system, comprising:
an individual sensor based on a low-temperature effect that outputs measurement signals, wherein the individual sensor includes an active sensor area, wherein the individual sensor has an operating temperature, and wherein the operating temperature of the individual sensor is stabilized by a temperature compenHohner;
a mechanical cooler that is thermally coupled to the individual sensor and produces a minimum cooling temperature T minK ;
a pre-amplifier connected to the individual sensor, wherein the pre-amplifier amplifies the measurement signals; and
sensor area enlargement means for producing an effective sensor area that is larger than the active sensor area of the individual sensor, wherein the minimum cooling temperature T minK fluctuates, and wherein the temperature compenHohner reduces the fluctuations of the minimum cooling temperature T minK to stabilize the operating temperature to within a range of +/−1 mK.
20. A method comprising:
(a) measuring temperature using a sensor, wherein the sensor is held at a temperature between 2.4 and 4.2 K, and wherein the sensor has an active sensor area of less than 50,000 μm 2 ;
(b) outputting a measurement signal; and
(c) amplifying the measurement signal using a pre-amplifier, wherein the pre-amplifier is held at a temperature between 2.4 and 4.2 K, wherein the sensor and the pre-amplifier are operated at the same temperature.
21. The method of claim 20 , wherein the sensor is a phase transition thermometer.
22. The method of claim 20 , wherein the sensor has an effective sensor area, further comprising:
(d) enlarging the effective sensor area using an X-ray lens.
23. The method of claim 20 , wherein the sensor has an effective sensor area, and wherein the effective sensor area is enlarged using a sensor matrix of individual sensors.
24. The method of claim 20 , wherein the sensor and the pre-amplifier are part of a single integrated circuit.
25. The method of claim 20 , wherein the measuring in (a) is performed in a scanning electron microscope.