CN116299636A

CN116299636A - Gamma ray detector

Info

Publication number: CN116299636A
Application number: CN202310159916.0A
Authority: CN
Inventors: 张雨禾; 徐利军; 高波; 刘蕴韬; 郝丽杰; 孟思勤; 王洪亮; 张俊博
Original assignee: China Institute of Atomic of Energy
Current assignee: China Institute of Atomic of Energy
Priority date: 2023-02-14
Filing date: 2023-02-14
Publication date: 2023-06-23

Abstract

The invention discloses a gamma ray detection device, wherein the gamma ray detection device comprises: a Printed Circuit Board (PCB); a gamma ray sensor chip and a SQUID amplifier chip are welded on the PCB; the gamma ray sensor chip at least comprises a first functional unit, and the SQUID amplifier chip at least comprises a second functional unit and a third functional unit; the first functional module is connected with the second functional unit through a wire; the first functional unit is used for receiving gamma rays to generate induction signals, the second functional unit is used for acquiring the induction signals and transmitting the induction signals to the third functional unit, and the third functional unit is used for amplifying the induction signals and converting the induction signals into output signals. The first functional unit is positioned on a first side of the gamma ray sensor chip, the second functional module is positioned on a second side of the SQUID amplifier chip, and the first side and the second side are two opposite and adjacent sides of the gamma ray sensor chip and the SQUID amplifier chip.

Description

Gamma ray detector

Technical Field

The invention relates to the technical field of computers, in particular to a gamma ray detection device.

Background

The low-energy gamma ray detection technology based on superconducting quantum interference devices (SQUID, superconducting Quantum Interference Device) can improve the radioactivity metering capability of low-energy gamma nuclides. The gamma ray sensor is used as an absorber, can absorb characteristic energy of gamma rays to generate induced current, and the current generated in the gamma ray sensor is amplified by the SQUID amplifier chip and finally converted into output voltage of a volt level. However, during the process of connecting the gamma-ray sensor with the SQUID amplifier chip, the gamma-ray sensor is affected by various factors, such as non-standardization of wires, so that the readout accuracy is affected.

Disclosure of Invention

In view of this, the embodiment of the invention provides a gamma-ray detection device, which aims to improve the stability and reliability of the gamma-ray detection result.

The technical scheme of the embodiment of the invention is realized as follows:

in one aspect, an embodiment of the present invention provides a gamma ray detection apparatus, including:

a Printed Circuit Board (PCB); a gamma ray sensor chip and a superconducting quantum interference device SQUID amplifier chip are welded on the PCB;

the gamma ray sensor chip at least comprises a first functional unit, and the SQUID amplifier chip at least comprises a second functional unit and a third functional unit; the first functional module is connected with the second functional unit through a wire; the first functional unit is used for receiving gamma rays to generate induction signals, the second functional unit is used for acquiring the induction signals and transmitting the induction signals to the third functional unit, and the third functional unit is used for amplifying the induction signals and converting the induction signals into output signals;

the first functional unit is located on a first side of the gamma-ray sensor chip, the second functional module is located on a second side of the SQUID amplifier chip, and the first side and the second side are two opposite and adjacent sides of the gamma-ray sensor chip and the SQUID amplifier chip.

In the above scheme, the lead is an aluminum wire.

In the above scheme, the length of the wire is smaller than a set value.

In the above scheme, the first functional unit is a magnetic induction coil, and the magnetic induction coil is covered with a paramagnetic material, and the paramagnetic material generates magnetic change when sensing gamma rays, and the magnetic change causes induced current to be generated in the magnetic induction coil;

the third functional module is used for amplifying the induced current and converting the induced current into output voltage.

In the scheme, the paramagnetic material is Jin Er Au-Er alloy.

In the above scheme, the magnetic induction coil is made of niobium Nb.

In the above scheme, the second functional unit is an input coil; the positive electrode and the negative electrode of the magnetic induction coil are respectively connected with the two stages of the input coil through wires; the third functional unit is a feedback coil.

In the above scheme, the wires are not overlapped with other wires on the PCB.

In the scheme, the anode and the cathode of the feedback coil are connected with a readout circuit at the room temperature end of the outside; the readout circuit is used for reading out the output voltage.

In the above scheme, the first functional unit is connected with a source meter at the external room temperature end through a Lei Mo LEMO connector; the source table is used for providing a current source for the gamma ray sensor chip

The gamma ray detection device provided by the embodiment of the invention is characterized in that a gamma ray sensor chip and a SQUID amplifier chip are welded on a PCB, wherein the gamma ray sensor chip at least comprises a first functional unit, the SQUID amplifier chip at least comprises a second functional unit and a third functional unit, and the first functional unit is connected with the second functional unit through a wire. The first functional unit is used for receiving gamma rays to generate induction signals, the second functional unit is used for acquiring the induction signals and transmitting the induction signals to the third functional unit, and the third functional unit is used for amplifying the induction signals and converting the induction signals into output signals. The first functional unit is positioned on a first side of the gamma-ray sensor chip, the second functional module is positioned on a second side of the SQUID amplifier chip, and the first side and the second side are two opposite and adjacent sides of the gamma-ray sensor chip and the SQUID amplifier chip. In the embodiment, as the two sides of the gamma-ray sensor chip and the SQUID amplifier chip, where the first functional unit and the second functional unit are arranged are opposite and adjacent, the position arrangement scheme comprehensively considers the convenience of wire binding and the connection reliability, so that the linear distance between the first functional unit and the second functional unit is shortest, the wire binding operation is convenient, the lap joint risk in the wire binding process is reduced, the stability and the reliability of the gamma-ray detection result are guaranteed to a certain extent, and the accuracy of the measurement result is guaranteed.

Drawings

Fig. 1 is a schematic diagram of a gamma-ray detection device according to an embodiment of the present invention;

FIG. 2 is a schematic diagram illustrating connection between a magnetic induction coil and an input coil according to an embodiment of the present invention;

fig. 3 is a schematic diagram of a PCB according to an embodiment of the present invention.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

Gamma rays (Gamma rays) are one type of electromagnetic waves, and are rays released when the nuclear energy level transition of atoms is deactivated.

At present, in the aspects of nuclear materials, homeland security, anti-terrorism, environmental protection, nuclear medicine and the like, the accurate measurement of nuclear attribution and nuclear nondiffusion depends on the distinction of gamma ray analysis with similar energy, wherein the low-energy gamma nuclide with characteristic energy positioned on a Compton platform has difficulty in realizing high-accuracy and high-resolution measurement by utilizing the traditional detection technology, and weak difference between isotope compositions is difficult to detect. The SQUID-based low-energy gamma ray detection technology can solve the problem, expand the detection lower limit and improve the low-energy gamma nuclide radioactivity metering capability.

Jin Er Au Er sensor is used as absorber, and the pick-up coil has the functions of providing magnetic field and picking up induced current. The current generated in the pick-up coil is amplified by the SQUID amplifier chip and ultimately converted to an output voltage in the order of volts. However, in the process of connecting the Au-Er sensor chip with the SQUID, the Au-Er sensor chip is affected by various factors, so that the reading accuracy is affected. For example, the wire-bonding method (because the size of the PCB and the chip is very small, the wires of the chip may overlap), the wire material, and the wire length all affect the measurement accuracy of the gamma spectrum.

In view of the above-mentioned drawbacks of the related art, an embodiment of the present invention provides a gamma ray detection device, in which positions of a gamma ray sensor chip and a SQUID amplifier chip are adjusted on a printed circuit board (PCB, printed Circuit Board) so that two sides of the gamma ray sensor chip and the SQUID amplifier chip where functional units connected to each other are located are adjacent to each other. Therefore, the distance between the gamma-ray sensor and the SQUID amplifier chip is shortest in the connection process, and the lap joint risk in the wire binding process is reduced, so that interference on gamma-ray energy spectrum measurement is reduced.

In order to illustrate the technical scheme of the invention, the following description is made by specific examples.

Fig. 1 is a schematic diagram of a gamma-ray detection device according to an embodiment of the present invention, where the gamma-ray detection device includes:

a Printed Circuit Board (PCB); a gamma ray sensor chip and a SQUID amplifier chip are welded on the PCB;

the gamma ray sensor chip at least comprises a first functional unit, and the SQUID amplifier chip at least comprises a second functional unit and a third functional unit; the first functional module is connected with the second functional unit through a wire; the first functional unit is used for receiving gamma rays to generate induction signals, the second functional unit is used for acquiring the induction signals and transmitting the induction signals to the third functional unit, and the third functional unit is used for amplifying the induction signals and converting the induction signals into output signals.

The gamma ray sensor chip comprises a plurality of functional units, at least a first functional unit is included, the first functional unit is a functional unit connected with the SQUID amplifier chip in the gamma ray sensor chip, and the gamma ray sensor is a sensor capable of sensing gamma rays and converting the gamma rays into sensing signals.

In practical application, 4 units, 2 as test units and 2 as functional units are placed on a silicon wafer of a gamma ray sensor chip. The testing unit is used for ensuring that parameters of the silicon wafer meet requirements in the wafer flowing process. The functional unit is used for detecting gamma signals.

SQUID is a device formed by a closed loop consisting of 1 or 2 josephson junctions (josephson junctions) and superconductors, and is mainly a high-precision magnetic sensor manufactured by combining the principles of josephson tunneling and magnetic flux quantization. In this embodiment, the SQUID amplifier chip is mainly used for receiving and amplifying the induction signal of the gamma-ray sensor chip.

When gamma rays are transmitted to a gamma ray sensor chip, the first functional unit generates induction signals according to the gamma rays, the induction signals are transmitted to the second functional unit through the lead wires, the second functional unit transmits the induction signals to the third functional unit, and the third functional unit amplifies the induction signals and converts the induction signals into output signals.

Here, the sensing signal may be a sensing current, and the output signal may be an output voltage.

As shown in fig. 1, the first functional unit and the second functional unit are located at adjacent sides of the gamma ray sensor chip and the SQUID amplifier chip, and fig. 1 is only an example, and may be two adjacent sides up and down, in addition to two adjacent sides.

Because the two sides of the first functional unit and the second functional unit are arranged in the gamma ray sensor chip and the SQUID amplifier chip adjacently, the straight line distance between the first functional unit and the second functional unit is shortest, and the wire binding operation is convenient. The position deployment scheme comprehensively considers the convenience and connection reliability of the binding wires, reduces the lap joint risk in the binding wire process, ensures the stability and reliability of the gamma ray detection result to a certain extent, and simultaneously ensures the accuracy of the measurement result.

In practical applications, this connection scheme can be implemented at mK temperature, which is the unit of measure of thermodynamic temperature.

In one embodiment, the wire is an aluminum wire.

The aluminum wire is in a superconducting state at the mK temperature, and no resistor is arranged in the aluminum wire under the superconducting state, so that the transmission of induction signals is convenient.

In practical application, the wire is an aluminum wire with a diameter of 25 um.

In one embodiment, the length of the wire is less than a set value.

The shorter the wire, the lower the loss of the transmission signal thereof, and thus the present embodiment limits the length of the wire between the first functional unit and the second functional unit to be smaller than the set value. The set value can be set according to practical situations, for example, the set value is 2mm.

In an embodiment, the first functional unit is a magnetic induction coil, and the magnetic induction coil is covered with a paramagnetic material, and the paramagnetic material generates a magnetic change when sensing gamma rays, and the magnetic change causes an induced current to be generated in the magnetic induction coil;

Here, paramagnetic field materials, i.e., materials having paramagnetic properties, are classified according to the magnitude and sign of susceptibility when magnetized by a magnet. After some substances are subjected to external magnetic field, the magnetization intensity in the same direction as the external magnetic field is induced, and the magnetic susceptibility is larger than zero, but the value is very small and is only 10 ^-6 ～10 ^-3 On the order of magnitude, such materials are known as paramagnetic materials. The magnetic susceptibility of paramagnetic substances is closely related to temperature. Paramagnetic substances include salts of rare earth metals and iron group elements, and the like.

When gamma rays (photons) strike the paramagnetic field material, the photons generate heat which is deposited on the paramagnetic field material, and the paramagnetic field material converts the heat into magnetic changes, and the magnetic changes cause induced currents to be generated in the magnetic induction coils. The third functional module amplifies the induced current and converts the induced current into an output voltage. The readout circuit at the external room temperature end can amplify and read out the output voltage.

In practice, the paramagnetic material may be coated onto the magnetic induction coil in the form of a coating.

In one embodiment, the paramagnetic material is an Au-Er alloy, and the Au-Er alloy is a paramagnetic material and has high sensitivity to magnetism and is used as a probe of a gamma-ray sensor, wherein the Au-Er alloy is a special film material formed by doping erbium elements into gold elements.

In an embodiment, the material of the magnetic induction coil is Nb.

The Nb coil is in a fully superconducting state at low temperature, in which the Nb coil has no resistance and the injection current is constant current, thereby generating a magnetic field.

When the paramagnetic material changes in magnetism, the magnetic flux of the underlying magnetic field is affected, thereby creating a small induced current in the Nb coil.

In an embodiment, the second functional unit is an input coil; the positive electrode and the negative electrode of the magnetic induction coil are respectively connected with the two stages of the input coil through wires; the third functional unit is a feedback coil.

Fig. 2 is a schematic diagram of connection between a magnetic induction coil and an input coil, as shown in fig. 2, wherein 1 is a gold palladium AuPd thermal resistor, 2 is a magnetic induction coil of a gamma ray sensor chip, 3 is an input coil of a SQUID amplifier chip, and positive and negative poles of the magnetic induction coil 2 are respectively connected with two stages of the input coil 3 through wires.

In one embodiment, the leads do not overlap with other leads on the PCB.

For example, the positive and negative electrodes of the magnetic induction coil are connected with the two stages of the input coil through wires respectively, and the 2 wires are not overlapped.

The interference to gamma ray energy spectrum measurement in the measurement process can be reduced by the non-lap joint between the wires, and the stability and the reliability of gamma ray detection results are guaranteed to a certain extent.

In one embodiment, the anode and the cathode of the feedback coil are connected with a readout circuit at the room temperature end of the outside; the readout circuit is used for reading out the output voltage.

The SQUID amplifier chip is composed of a plurality of Josephson junctions and mainly comprises a detection SQUID at the front end and an amplified SQUID at the rear end, wherein the detection SQUID at the front end is used as a second functional unit, and the second functional unit is an input coil; the amplified SQUID at the back end serves as a third functional unit, which is a feedback coil.

After the induction signal enters the feedback coil from the input coil, the feedback coil amplifies the induction signal.

The positive electrode and the negative electrode of the feedback coil are connected with a readout circuit at the external room temperature end, and the readout circuit is used for reading out output voltage so that a user can directly observe the gamma ray detection result.

In one embodiment, the first functional unit is connected to a source meter at the ambient room temperature end through a Lei Mo LEMO connector; the source table is used for providing a current source for the gamma ray sensor chip.

The LEMO connector is a universal connector, and the first functional unit is connected with a source meter at the room temperature end of the outside through the LEMO connector, the LEMO connector has a single core, 9 cores, 24 cores and the like, the type of the LEMO connector is not limited in this embodiment, and any LEMO connector can be used.

The source list is a current source or voltage source that can be used to supply a minute current to the first functional unit. In practical applications, a digital source table of model number Shi Li 2400 or model number 2460 may be used.

As shown in fig. 3, fig. 3 is a schematic diagram of a PCB according to an embodiment of the present invention. The Au-Er sensor chip and the SQUID amplifier chip are arranged on the PCB together, the size of the Au-Er sensor chip is 10mm by 10mm, the size of the SQUID amplifier chip is 5mm by 5mm, and the size of the sample placement area is 12mm by 17.5mm. An Au-Er sensor chip is arranged on the left side of the PCB, and an Nb coil (a first functional unit) is arranged on the right side of the Au-Er sensor; the SQUID amplifier chip is placed on the right side of the PCB, and the input coil (second functional unit) is placed on the left side of the SQUID amplifier chip.

In fig. 3, 1 to 12 are solder pads on the PCB, and 1 to 12 are connected to the source table. 13 is the positive pole of the SQUID amplifier, 14 is the negative pole of the SQUID amplifier, 15 is the ground of the SQUID amplifier, 16 is the negative pole of the feedback coil of the SQUID amplifier, and 17 is the positive pole of the feedback coil of the SQUID amplifier.

The pad is a pin of a silicon chip, is packaged inside the chip and cannot be seen by a user. There is also a wire connection between pad and pin. bonding refers to bonding, which refers to securing a wafer die to a substrate in a semiconductor process.

bonding pad refers to the bond pad on the chip to the PCB through which it can be directly connected to the inside of the chip.

Four aluminum wires are required to be connected to the bonding pad on the PCB when the Au/Er sensor is injected with current, and 1, 2, 11 and 12 in FIG. 3 are respectively connected with positive and negative stages of the Nb coil of the Au/Er sensor chip. 5. And 6, 7 and 8 are connected with a gold-palladium AuPd thermal resistor of the Au-Er sensor chip.

Five aluminum wires are required for the SQUID to connect to the external room temperature circuit, as shown at 13 to 17 in fig. 3.

The Au Er sensor chip and the SQUID amplifier chip are connected by an aluminum wire with the diameter of 25 um.

Meanwhile, in order to ensure the accuracy of signal transmission, the Au-Er sensor chip is provided with a bonding pad at the anode and the cathode of the Nb coil and is connected with the input coil of the SQUID amplifier by two aluminum wires. In fig. 3, the two aluminum wires are not overlapped, so that accuracy of the induced current generated by the Au-Er sensor chip when the induced current is transmitted to the SQUID amplifier chip is improved, normal operation of the chip is ensured, and convenience and reliability are achieved.

The embodiment can be applied to a metal magnetic gamma-ray calorimeter, wherein 25 mu Al wires are used for respectively connecting the two ends of an AuPd thermal resistor and an Nb coil with four bonding pads connected with a single-core Ramer joint, connecting the anode and the cathode of the Nb coil with the two poles of an input coil on a SQUID amplifier chip, and connecting

pins

16 and 17 of the SQUID amplifier with corresponding pads of a room temperature readout circuit, wherein the distance is shortest in the connection process and no binding wire is lapped. When the Au-Er sensor chip receives signals, the signals can be normally and quickly transmitted to the SQUID amplifier chip and read out at the room temperature end.

In practical applications, the PCB is placed at mk low temperature level and measured by a readout circuit at room temperature.

The embodiment improves the accuracy of the induced current generated when gamma rays strike an Au: er sensor chip and are transmitted to a SQUID amplifier chip. Meanwhile, in design, the space connection among different chips is considered, so that signals can be accurately injected into the sensor chip, and reading is realized at the room temperature end. The interference to gamma ray energy spectrum measurement in the measurement process is reduced, the connection scheme can be realized at the mK temperature, the lap joint risk in the wire binding process is reduced, the chip can work normally, the convenience and the reliability are realized, and meanwhile, the stability and the reliability of a gamma ray detection result are guaranteed to a certain extent.

It should be understood that the sequence number of each step in the foregoing embodiment does not mean that the execution sequence of each process should be determined by the function and the internal logic, and should not limit the implementation process of the embodiment of the present invention.

It should be understood that the terms "comprises" and "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

The technical schemes described in the embodiments of the present invention may be arbitrarily combined without any collision.

In addition, in the embodiments of the present invention, "first", "second", etc. are used to distinguish similar objects and are not necessarily used to describe a particular order or precedence.

The foregoing is merely specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily think about changes or substitutions within the technical scope of the present application, and the changes and substitutions are intended to be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A gamma ray detection device, the device comprising:

2. The device of claim 1, wherein the wire is aluminum wire.

3. A device according to any one of claims 1 to 2, wherein the length of the wire is less than a set point.

4. The device of claim 1, wherein the first functional unit is a magnetic induction coil covered with a paramagnetic material that produces a magnetic change when gamma rays are sensed, the magnetic change causing an induced current to be generated in the magnetic induction coil;

5. The device of claim 4, wherein the paramagnetic material is Jin Er Au in Er alloy.

6. The apparatus of claim 4, wherein the material of the magnetic induction coil is niobium Nb.

7. The apparatus of claim 4, wherein the second functional unit is an input coil; the positive electrode and the negative electrode of the magnetic induction coil are respectively connected with the two stages of the input coil through wires; the third functional unit is a feedback coil.

8. The apparatus of claim 7, wherein the wire does not overlap with other wires on the PCB.

9. The device of claim 7, wherein the positive and negative poles of the feedback coil are connected to a readout circuit at the ambient room temperature end; the readout circuit is used for reading out the output voltage.

10. The apparatus of claim 1, wherein the first functional unit is connected to a source meter at ambient room temperature via a Lei Mo LEMO connector; the source table is used for providing a current source for the gamma ray sensor chip.