Silicon drift detector and detector system with self-leak detection and temperature control functions

Abstract

The present invention discloses a silicon drift detector and a detector system with self-leak detection and temperature control functions, wherein a collimator in a housing cavity of a shell is connected to a silicon drift detection element; an amplifier is electrically connected to the silicon drift detection element and is used to amplify the output signal of the silicon drift detection element; a ceramic base is connected to the silicon drift detection element and is arranged on a side of the silicon drift detection element away from the collimator; wherein at least two grooves are provided on the surface of the ceramic base, and an absolute pressure sensor and / or a temperature sensor are embedded in the grooves, and the absolute pressure sensor and the temperature sensor are used to output pressure signals and temperature signals to the outside; a refrigerator is provided at one end of the ceramic base away from the silicon drift detection element and is used to maintain the temperature inside the shell; the installation positions of the absolute pressure sensor and the temperature sensor are reasonably designed to provide a silicon drift detector with self-leak detection and temperature control functions without increasing the overall design volume and ensuring that the internal structure does not have structural interference.

Description

Technical Field

[0001] The present invention relates to the technical field of silicon drift detectors, and in particular to a silicon drift detector with self-leakage detection and temperature control functions and a detector system. Background Art

[0002] Silicon drift detectors (SDDs) hold a special place in high-energy physics and aerospace due to their high energy resolution. Applications include vertex detectors in large accelerators and detector systems for pulsar navigation. Furthermore, their high sensitivity and high count rate have led to their widespread application in industrial, medical, and safety testing applications, such as spectroscopy, nondestructive testing, and industrial flaw detection. Their primary structure consists of a block of low-doped, high-resistance silicon with a thin abrupt junction at the backside where radiation enters. The front-side doped electrodes are designed as closely spaced concentric ring stripes, forming multiple drift rings. A reverse bias field gradually increases between the electrodes, generating an electric field component parallel to the surface. In the depletion layer, electrons generated by ionizing radiation are driven by this electric field and "drift" toward the extremely low-capacitance collecting anode, generating electrical pulses and counting signals. This allows for high sensitivity in detecting weak signals. The SDD is mounted on an automatically temperature-controlled cooler using semiconductor packaging technology to minimize the impact of ambient temperature on weak signal detection efficiency and filter stray light signals through a Be window.

[0003] The working efficiency of the SDD is also affected by its internal temperature and airtightness. However, the existing structure cannot monitor the airtightness and temperature conditions inside the silicon drift detector in real time. Therefore, the data accuracy of the silicon drift detector cannot be effectively guaranteed. In addition, the lack of favorable monitoring methods makes it unfavorable for daily maintenance. Summary of the Invention

[0004] In view of the problem in the prior art that the air tightness and temperature inside the SDD structure cannot be monitored, the present application provides a technical solution to solve the problem.

[0005] To achieve the above-mentioned object, the present invention provides a silicon drift detector with self-leak detection and temperature control functions, comprising a housing, the housing having an incident window formed therein for radiation injection; and further provided within a receiving cavity of the housing:

[0006] A silicon drift detection element, wherein the first surface is arranged corresponding to the incident window;

[0007] a collimator connected to the silicon drift detection element and disposed on a side of the first surface close to the incident window;

[0008] an amplifier, electrically connected to the silicon drift detection element, and configured to amplify an output signal of the silicon drift detection element;

[0009] a ceramic base connected to the silicon drift detection element and disposed on a side of the silicon drift detection element away from the collimator; wherein the surface of the ceramic base is provided with at least two grooves, wherein an absolute pressure sensor and / or a temperature sensor are embedded in the grooves, and the absolute pressure sensor and the temperature sensor are used to output pressure signals and temperature signals to the outside world;

[0010] A refrigerator is provided at one end of the ceramic base away from the silicon drift detection element and is used for maintaining the temperature inside the shell.

[0011] Preferably, the collimator is a collimating circular ring structure, and one or more notches are provided on the outer ring edge of the collimating circular ring structure, and the temperature sensor or the absolute pressure sensor is provided in the notch.

[0012] Preferably, a heat-insulating gasket is further provided on a side of the collimator close to the incident window, and an orthographic projection area of ​​the heat-insulating gasket on the silicon drift detection element is smaller than or equal to an orthographic projection area of ​​the collimator on the silicon drift detection element.

[0013] Preferably, the ceramic base is a boron nitride ceramic base or a silicon nitride ceramic base; the silicon drift detection element is mounted on the surface of the ceramic base, and a plurality of electrode solder joints are provided on the edge of the ceramic base, the electrode solder joints are electrically connected to the silicon drift detection element and the amplifier, and the electrode solder joints are also connected to lead wires, which are used to output signals to the outside world and provide operating voltage to the silicon drift detector element.

[0014] Preferably, the output ends of the absolute pressure sensor and the temperature sensor output pressure signals and temperature signals to the outside world through the electrode welding points;

[0015] The amplifier includes a field effect transistor, which is attached to the edge of the silicon drift detection element. The input end of the field effect transistor is coupled to the output end of the silicon drift detection element, and the output end of the field effect transistor is coupled to the electrode pad.

[0016] Preferably, the groove is provided at the corner structure of the ceramic base, and the groove is designed to avoid the electrode welding point.

[0017] Preferably, the electrode solder joints are gold solder joints; the lead wires are gold leads;

[0018] A lead post is provided at one end of the shell away from the incident window. The part of the lead post located inside the shell is fixedly connected to the gold lead, and a gap is set between the lead post and the cooler; and a heat-conducting post is also provided on the outer surface of the shell, and the heat-conducting post is arranged in the middle part surrounded by multiple lead posts.

[0019] Preferably, the portion where the lead post intersects the shell is filled and sintered to form a glass glaze structure layer; and the lead post is sheathed with a ceramic tube.

[0020] Preferably, the pressure sensor is a silicon absolute pressure sensor, and the temperature sensor is a platinum resistance temperature sensor.

[0021] Also disclosed is a silicon drift detector system, comprising the above-mentioned silicon drift detector, and also comprising an electrically connected signal processing unit, a temperature signal unit and a pressure signal unit; the signal processing unit is used to receive the detection signal of the silicon drift detection element after being amplified by an amplifier, the temperature signal unit is used to process the temperature signal, and the pressure signal unit is used to process the pressure signal; the signal processing unit adjusts a refrigerator in response to the temperature signal; when the pressure signal exceeds a set threshold, the signal processing unit issues an alarm signal and stops the operation of the silicon drift detector.

[0022] The beneficial effects of the present invention are as follows: the present invention discloses a silicon drift detector with self-leak detection and temperature control functions, comprising a shell, the shell being formed with an incident window for radiation incidence; a silicon drift detection element being further arranged in a receiving cavity of the shell, with a first surface being arranged corresponding to the incident window; a collimator being connected to the silicon drift detection element and arranged on a side of the first surface close to the incident window; an amplifier being electrically connected to the silicon drift detection element and used to amplify an output signal of the silicon drift detection element; a ceramic base being connected to the silicon drift detection element and arranged on a side of the silicon drift detection element away from the collimator; wherein the surface of the ceramic base is provided with at least two grooves, in which an absolute pressure sensor and / or a temperature sensor are embedded, the absolute pressure sensor and the temperature sensor being used to output pressure signals and temperature signals to the outside; a cooler being arranged at one end of the ceramic base away from the silicon drift detection element and used to maintain the temperature inside the shell; and the silicon drift detector with self-leak detection and temperature control functions can be provided without increasing the overall design volume and ensuring that the internal structure does not have structural interference. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is the overall structural diagram of the present invention;

[0024] Figure 2 An exploded view of the present invention;

[0025] Figure 3 This is a structural diagram of the silicon drift detection element of the present invention;

[0026] Figure 4 This is a structural diagram of the ceramic base of the present invention;

[0027] Figure 5This is a structural diagram of the lead column of the present invention;

[0028] Figure 6 It is the internal structure diagram of the present invention.

[0029] The main component symbols are described as follows:

[0030] 1. Shell; 11. Shell bottom substrate; 12. Lead pin; 121. Glass glaze structure layer; 122. Ceramic tube; 123. Gold wire; 13. Thermal conductive column;

[0031] 2. Entrance window; 21. Beryllium plate;

[0032] 3. Silicon drift detection element;

[0033] 4. Collimator; 41. Notch; 42. Thermal insulation gasket;

[0034] 5. Amplifier;

[0035] 6. Ceramic base; 61. Groove; 611. Absolute pressure sensor; 612. Temperature sensor; 62. Electrode welding point;

[0036] 7. Refrigerator;. DETAILED DESCRIPTION

[0037] In order to more clearly illustrate the present invention, the present invention will be further described below with reference to the accompanying drawings.

[0038] In the following description, details of general examples are provided to provide a deeper understanding of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, and are not intended to be exhaustive. It should be understood that the specific embodiments described are intended only to illustrate the present invention and are not intended to limit the present invention.

[0039] It should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the existence of features, integers, steps, operations, elements or components, but do not exclude the existence or addition of one or more other features, integers, steps, operations, elements, components or their combinations.

[0040] This application discloses a silicon drift detector with self-leakage detection and temperature control functions. Figure 1-Figure 2 、 Figure 6 The housing 1 includes an incident window 2 formed therein for radiation input. As is known, the incident window is only for allowing X-rays to enter, and does not represent an open window. Specifically, to ensure airtightness and permeability while not blocking or significantly attenuating incident radiation, a beryllium sheet 21 is preferably used. Brazing is used to secure the sheet to the housing to ensure high airtightness. Furthermore, the housing 1 includes:

[0041] The silicon drift detection element 3 can be specifically a detector chip; the first surface of the silicon drift detection element is arranged corresponding to the incident window; silicon drift detection elements are disclosed in a variety of forms in the prior art. The first surface of the silicon drift detection element has a very thin homogeneous abrupt junction as the radiation source, and the heterogeneous doped electrodes on the second surface are designed as closely spaced stripes, usually in the shape of concentric rings. The reverse bias field gradually increases between the electrodes, forming an electric field component parallel to the surface. In the depletion layer, electrons generated by ionizing radiation are driven by this electric field force and drift toward the extremely low-capacitance collection anode, forming a counting current;

[0042] A collimator 4 is connected to the silicon drift detector element 3 and is disposed on a side of the first surface near the incident window. The collimator is specifically an optical collimator. The collimator ensures that the X-rays incident in the vertical direction are most efficient and minimize the impact of lateral diffraction or scattering on the silicon drift detector element. The collimator can be made of nickel, copper, nickel-copper alloy, or other materials with similar functions.

[0043] An amplifier 5 is electrically connected to the silicon drift detection element and is used to amplify the output signal of the silicon drift detection element. The amplifier includes a field-effect transistor and is further provided with a surface-mount resistor, which is used to feedback the amplification effect of the amplifier, i.e., the feedback resistor for coupling the detector to the amplifier. The surface-mount resistor, the silicon drift detection element, and the field-effect transistor are integrated on the same substrate.

[0044] The ceramic base 6 is connected to the silicon drift detection element 3 and is arranged on the side of the silicon drift detection element 3 away from the collimator; wherein, the surface of the ceramic base 6 is provided with at least two grooves 61, and the grooves 61 are embedded with an absolute pressure sensor 611 and / or a temperature sensor 612, and the absolute pressure sensor 611 and the temperature sensor 612 are used to output pressure signals and temperature signals to the outside world; since the overall structure of the silicon drift detector is limited by other external components, the volume design is relatively fixed. At the same time, in order to ensure the airtightness and temperature consistency of the internal working environment, the internal cavity space is basically occupied by the solid structure, so it can be attached. The structural space of the added design is very small, and there are many internal structures. Without precise design, structural interference is likely to occur. Therefore, this solution adopts the method of digging grooves at the corners of the ceramic base. The grooves formed are used to place the absolute pressure sensor and / or temperature sensor. This will neither interfere with the original structure nor affect the overall volume design. At the same time, the ceramic base serves as the substrate of the silicon drift detection element and has high thermal conductivity and good stability. Placing the absolute pressure sensor and temperature sensor in the grooves in the corners will not affect their thermal conductivity and can accurately monitor the temperature and pressure of the internal space of the detector.

[0045] A cooler 7 is located at the end of the ceramic base away from the silicon drift detector element and is used to maintain the temperature inside the housing. The cooler typically utilizes a semiconductor refrigeration device, which features refrigerant-free operation, continuous operation, zero pollution, simple structure, low noise, long life, high efficiency, low power consumption, and easy control and operation. It can provide both cooling and heating, allowing the detector to operate at room temperature or in deep space or extreme environments. More specifically, the coolers can be arranged in multiple stages, interconnected in parallel on the bottom substrate of the housing. The bottom substrate 11 of the housing is an aluminum oxide ceramic substrate with leads on the substrate for parallel connection. Temperature maintenance, then, means maintaining the internal working environment of the detector within a set range through the heat transfer function of the cooler. The semiconductor refrigeration device operates based on the Peltier principle. When current flows through a thermocouple connecting an n-type semiconductor (Bi2Te3-Bi2Se3) and a p-type semiconductor (Bi2Te3-Sb2Te3), heat transfer occurs between the two ends, forming a temperature difference between the hot and cold ends. This heat is then radiated outward through the housing to maintain temperature. It is worth noting that, in addition to being fixed by welding, all internal components that need to be fixed are fixed and bonded using conductive and thermally conductive low-temperature glue.

[0046] In this example, see Figure 3 ; The collimator 4 is a collimating ring structure, and one or more notches 41 are provided on the outer ring edge of the collimating ring structure, and a temperature sensor 612 or other type of sensor is provided in the notch 41; the middle window of the collimator ring structure is the incident window of the ray, and the notch is the location of the cathode lead of the silicon drift detection element, and the structure that is avoided on the silicon drift detection chip substrate can be mounted with a temperature sensor element, which can make full use of the structural space and meet the requirements of accurate temperature measurement.

[0047] In this embodiment, a thermally insulating spacer 42 is provided on the side of the collimator 4 near the incident window. The orthographic projection area of ​​the thermally insulating spacer 42 on the silicon drift detector element is less than or equal to the orthographic projection area of ​​the collimator on the silicon drift detector element. In other words, the thermally insulating spacer has the same cross-sectional size as the collimator and does not affect the incident area of ​​the X-rays. Furthermore, the thermally insulating spacer is intended to reduce the impact of temperature on the operation of the silicon drift detector element and ensure detection stability.

[0048] In this example, see Figure 5The ceramic base 6 is a boron nitride ceramic base or a silicon nitride ceramic base. The silicon drift detection element is mounted on the surface of the ceramic base and located in the center. Specifically, a hollow or gap is reserved between the silicon drift detection element and the ceramic base during mounting to ensure that the electrode wires can be properly led out. The edge of the ceramic base is also provided with multiple electrode solder joints. The electrode solder joints 62 are electrically connected to the silicon drift detection element and the amplifier. The electrode solder joints are also connected to lead wires, which are used to output signals to the outside world and also provide operating voltage to the silicon drift detection element. The electrode solder joints are used to lead out the electrical signals generated by the silicon drift detection element and transmit temperature and pressure signals.

[0049] In this embodiment, the output ends of the absolute pressure sensor and the temperature sensor output pressure signals and temperature signals to the outside world through electrode solder joints; the electrode solder joints can specifically be gold-plated electrodes to ensure connection stability;

[0050] The amplifier includes a field-effect transistor (FET), which can be a junction field-effect transistor (JFET) or a CMOS operational amplifier. The FET is attached to the edge of the silicon drift detection element, with the FET's input coupled to the FET's output, and the FET's output coupled to the electrode pad. The amplifier and the silicon drift detection element can be two independent chips for signal processing. The temperature sensor can be a plurality of temperature-measuring diodes, whose lead pins are connected to the electrode pads via gold wires 123 by pressure welding. The temperature-measuring diodes can be bonded to the surface of the ceramic base using a thin-film construction process or printing and sintering.

[0051] In this embodiment, a groove is provided at the corner structure of the ceramic base, and the groove is designed to avoid the electrode welding point.

[0052] In this example, see Figure 5 ; Electrode solder joints are gold solder joints or gold-plated electrodes; lead wires are gold leads;

[0053] A lead pin 12 extends through the housing 1 at one end, away from the incident window. The portion of the lead pin 12 located within the housing is fixedly connected to a gold lead wire, and a gap is provided between the lead pin 12 and the cooler 7. Furthermore, a heat-conducting column 13 is provided on the outer surface of the housing, positioned in the middle of the area surrounded by the multiple lead pins. Specifically, the heat-conducting column 13 is connected to the base of the housing, thereby radiating heat to the outside of the housing.

[0054] In this embodiment, the part where the lead post 12 intersects with the shell is filled and sintered to form a glass glaze structural layer 121; the glass glaze structural layer can ensure good airtightness at the gap and at the same time ensure the stability of the structure; and the lead post is sleeved with a ceramic tube 122; it is to avoid electrical contact between the lead post and the refrigerator and the shell, and to avoid damage due to structural interference.

[0055] In this embodiment, the pressure sensor is a silicon absolute pressure sensor, and the temperature sensor is a platinum resistance temperature sensor.

[0056] Also disclosed is a silicon drift detector system, comprising the above-mentioned silicon drift detector, and also comprising an electrically connected signal processing unit, a temperature signal unit, and a pressure signal unit; the detection signal of the silicon drift detection element is amplified by an amplifier and received by the signal processing unit, the temperature signal unit is used to process the temperature signal, and the pressure signal unit is used to process the pressure signal; the signal processing unit adjusts the refrigerator in response to the temperature signal; when the pressure signal exceeds a set threshold, the signal processing unit sends an alarm signal and stops the silicon drift detector from operating.

[0057] The advantages of the present invention are:

[0058] It is possible to provide a silicon drift detector with self-leak detection and temperature control functions without increasing the overall design volume and ensuring that there is no structural interference in the internal structure.

[0059] The above disclosures are only several specific embodiments of the present invention, but the present invention is not limited thereto. Any changes that can be conceived by those skilled in the art should fall within the scope of protection of the present invention.

Claims

1. A silicon drift detector with self-leak detection and temperature control functions, comprising a housing, wherein the housing is formed with an incident window for radiation incidence; characterized in that: The housing cavity of the housing is further provided with: A silicon drift detection element, wherein the first surface is arranged corresponding to the incident window; a collimator connected to the silicon drift detection element and disposed on a side of the first surface close to the incident window; an amplifier, electrically connected to the silicon drift detection element, and configured to amplify an output signal of the silicon drift detection element; a ceramic base connected to the silicon drift detection element and disposed on a side of the silicon drift detection element away from the collimator; wherein the surface of the ceramic base is provided with at least two grooves, wherein an absolute pressure sensor and / or a temperature sensor are embedded in the grooves, and the absolute pressure sensor and the temperature sensor are used to output pressure signals and temperature signals to the outside world; A refrigerator is provided at one end of the ceramic base away from the silicon drift detection element, and is used to maintain the temperature inside the housing; In which, the ceramic base is a boron nitride ceramic base or a silicon nitride ceramic base; the silicon drift detection element is mounted on the surface of the ceramic base, and a plurality of electrode welding points are also provided on the edge of the ceramic base, the electrode welding points are electrically connected to the silicon drift detection element and the amplifier, and the electrode welding points are also connected to lead wires, the lead wires are used to output signals to the outside world and provide the working voltage of the silicon drift detection element; the electrode welding points are gold welding points; the lead wires are gold leads; a lead column is provided at one end of the shell away from the incident window, the part of the lead column located in the shell is fixedly connected to the gold lead, and a gap is set between the lead column and the cooler; and a heat-conducting column is also provided on the outer surface of the shell, and the heat-conducting column is provided in the middle part surrounded by multiple lead columns.

2. The silicon drift detector with self-leak detection and temperature control functions according to claim 1, characterized in that: The collimator is a collimating circular ring structure, and one or more notches are provided on the outer ring edge of the collimating circular ring structure, and the temperature sensor or the absolute pressure sensor is provided in the notch.

3. The silicon drift detector with self-leak detection and temperature control functions according to claim 2, characterized in that: A heat-insulating gasket is further provided on one side of the collimator close to the incident window, and an orthographic projection area of ​​the heat-insulating gasket on the silicon drift detection element is smaller than or equal to an orthographic projection area of ​​the collimator on the silicon drift detection element.

4. The silicon drift detector with self-leak detection and temperature control functions according to claim 1, characterized in that: The output ends of the absolute pressure sensor and the temperature sensor output pressure signals and temperature signals to the outside world through the electrode welding points; The amplifier includes a field effect transistor, which is attached to the edge of the silicon drift detection element. The input end of the field effect transistor is coupled to the output end of the silicon drift detection element, and the output end of the field effect transistor is coupled to the electrode pad.

5. The silicon drift detector with self-leak detection and temperature control functions according to claim 1, characterized in that: The groove is provided at the corner structure of the ceramic base, and the groove avoids the electrode welding point design.

6. The silicon drift detector with self-leak detection and temperature control functions according to claim 1, characterized in that: The intersection of the lead post and the shell is filled and sintered to form a glass glaze structure layer; the lead post is sheathed with a ceramic tube.

7. The silicon drift detector with self-leak detection and temperature control functions according to claim 1, characterized in that: The absolute pressure sensor is a silicon absolute pressure sensor, and the temperature sensor is a platinum resistance temperature sensor.

8. A silicon drift detector system, characterized in that: The silicon drift detector comprises the silicon drift detector according to any one of claims 1 to 7, and further comprises a signal processing unit, a temperature signal unit and a pressure signal unit which are electrically connected; the signal processing unit is used to receive the detection signal of the silicon drift detection element after being amplified by an amplifier, the temperature signal unit is used to process the temperature signal, and the pressure signal unit is used to process the pressure signal; the signal processing unit adjusts a refrigerator in response to the temperature signal; when the pressure signal exceeds a set threshold, the signal processing unit sends an alarm signal and stops the operation of the silicon drift detector.

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