RU204784U1 - UNIVERSAL SEMICONDUCTOR SPECTROMETER FOR DETECTING CORPUSCULAR SPACE RADIATIONS - Google Patents

Abstract

The utility model relates to semiconductor spectrometers for detecting corpuscular cosmic radiation, which can be used on ultra-small spacecraft of the CubeSat type. Essence: the spectrometer includes an assembly of three printed circuit boards (1) and one digital signal processing board (2) located one above the other with a gap, installed at the ends between two walls (6). Each of the three printed circuit boards (1) contains a semiconductor detector (5) equipped with a passive protection device (3), and an amplifier and signal conditioning unit located close to the detector (5). In this case, the detectors (5) of all three boards (1) are located coaxially. The digital signal processing board (2) contains a microcontroller, a flash memory device, and an external interface driver microcircuit. From the side of the first printed circuit board (1), the spectrometer is closed by a cover with an opening for the flow of charged particles. EFFECT: improved spectrometric characteristics of the detector due to its location on the same board with the amplification and signal shaping path, which excludes the possibility of using unshielded wires when connecting the detector and, as a consequence, allows the spectrometer to be used on ultra-small spacecraft. 2 c.p. f-ly, 3 dwg

Description

Technology area

The utility model relates to the field of detecting corpuscular cosmic radiation and can be used on ultra-small spacecraft of the CubeSat type (cubsat). Detection devices use the principle of sequential registration of a passing charged particle by several semiconductor detectors of different thickness to determine its type and energy.

The claimed universal semiconductor spectrometer is designed to register the fluxes of electrons and protons of natural cosmic radiation in the energy range from 50 keV to 10 MeV (for electrons) and from 1 MeV to 200 MeV (for protons).

State of the art

Semiconductor telescopes, i.e. coaxial assemblies of semiconductor detectors are quite traditional devices for recording energetic charged particle fluxes. The advantages of devices of this type are high spectrometric characteristics, a large dynamic range of use, the ability to determine the type of charged particles without using complex mathematical methods.

Known "multichannel semiconductor detector for registration of alpha particles in a neutron generator with a static vacuum and a sensitive element for it", disclosed in patent RU 2476907. The known detector includes a housing, a semiconductor crystal plate, placed perpendicular to the flow of alpha particles on a ceramic plate, recording elements in the form of strips with electrical contacts and down conductors.

The disadvantage of this invention is its limitation in the direction of the registered alpha particles: the device is designed for a specific location of the source and cannot be used to register natural sources in space. The overall dimensions of the known detector do not allow it to be used in spacecraft of the Cubsat type.

Known RF patent No. 2550313 "Spectrometer-radiometer for the simultaneous analysis of the characteristics of mixed fields of alpha-beta and gamma radiation based on a composite detector", which discloses the design of the spectrometer, which can be used for the simultaneous registration of alpha, beta and gamma radiation ... The spectrometer-radiometer includes a semiconductor silicon detector, scintillators with different illumination times, a device for separating signals by pulse shape parameters, an amplifier, a signal pulse shape digitizing device, a threshold discriminator-shaper, a digital integrator for processing signals from a semiconductor detector, and a memory device for storing spectra. alpha radiation, coincidence scheme and anti-coincidence scheme. This invention can be used for radiation monitoring of the environment, that is, for measuring several types of radiation, which is a common feature with the claimed technical solution.

The disadvantage of this device is the low accuracy of energy determination, due to the use of scintillators, in comparison with semiconductor telescopes without scintillation detectors.

Known RF patent No. 2615709, disclosing "a device for measuring the neutron flux density of a nuclear power plant in conditions of background interference from gamma quanta and high-energy space electrons and protons." This device implements a circuit for distinguishing the measurement of the neutron flux density generated by a nuclear power plant located on a spacecraft from background interference from gamma quanta of a nuclear power plant and high-energy space electrons and protons.

The disadvantage of this device is the lack of registration of low-energy background radiation of electrons, protons and gamma-quanta, which are absorbed by the protective case.

Closest to the claimed utility model is the solution disclosed in RF patent No. 165028 "Spectrometer of energetic cosmic radiation (SPER)", and is intended for measuring fluxes, energy spectra and time variations of energetic cosmic protons and electrons. This device, in addition to semiconductor detectors, contains a scintillation crystal, which significantly increases the upper energy threshold of the registered charged particles.

The disadvantages of this device include its significant dimensions and weight, as well as an outdated electronic component base, significant sensitivity to interference, complexity in manufacturing and tuning, the impossibility of changing settings after manufacturing, the need for external interface devices for connection and operation.

Disclosure of a utility model

The technical result achieved when using the claimed utility model is to improve the spectrometric characteristics of the detector due to the location of the semiconductor detector on the same board with the amplification and signal shaping path, which, inter alia, excludes the possibility of using unshielded wires when connecting the detector and, as a consequence, allows you to use the claimed spectrometer on ultra-small spacecraft.

The advantages of the claimed utility model are also significantly lower weight and size characteristics, improved noise parameters compared to the prototype, the ability to control and adjust during operation, significantly increased manufacturability and adjustment, the ability to remove telemetric parameters and diagnose its own state during operation. The signal-to-noise ratio in the claimed spectrometer is increased at least twice as compared to the prototype.

The claimed technical result is achieved by the fact that a universal semiconductor spectrometer for detecting corpuscular cosmic radiation includes an assembly of four printed circuit boards located one above the other with a gap, with ends installed between two walls, while each of the first three boards contains a semiconductor detector equipped with a passive protection device and an amplifier and signal conditioning unit located close to the detector, and the fourth board is a digital signal processing board, on which a microcontroller, a flash memory device and an external interface driver chip are located, while the detectors of all three boards are located coaxially, and from the side of the first board the device is closed with a lid with an opening for the flow of charged particles. The semiconductor detector is a silicon semiconductor detecting element 300 μm thick with a square active area of 1 x 1 cm. The device for passive protection of detectors is made in the form of a bronze ring installed in the gap between the corresponding printed circuit boards.

The utility model is illustrated by the following drawings, where

in fig. 1 shows the layout of the detector boards in the telescope,

in fig. 2 shows an example of a preprocessed signal,

in fig. 3 shows a schematic layout of a device for installation in a spacecraft of the CubeSat 1U, 2U and larger format (dimensions according to the CubeSat CDS rev. 13 standard, seats according to the PC / 104 standard, side cutouts for through passage of cable bundles according to the Pumpkin recommendation).

Positions in the figures indicate:

1. detector boards,

2.digital signal processing board,

3.Bronze rings for passive protection of detectors,

4.Area of electronics placement,

5.silicon detectors on boards,

6.the wall of the detector housing,

7.through connectors,

8.trigger signal,

9.fast component of the amplified signal,

10.slow component of the amplified signal,

11.bore holes according to PC / 104 standard,

12. detector field of view and collimator.

Implementation of the utility model.

The device is an assembly of four sequentially superimposed on each other electronics boards (item 1 in Fig. 1, 3), arranged in the process of using the device in a stack perpendicular to the direction of the flow of registered particles, as shown in Fig. 1, 3. The boards are clamped from the ends by two walls (item 6 in Fig. 3), which determine the overall geometry of the device in accordance with the CubeSat CDS rev.13 standard. They have fastening holes for the M3 thread, located according to the PC / 104 standard (item 11 in Fig. 3). The shape of the walls provides side cutouts to pass through the bundles of cables of other devices according to the Pumpkin industry recommendation for spacecraft of the CubeSat 1U… 3U frame size.

On the side of the first plate with a gap, a cover with an opening for passing the particle flow is installed thereto (Fig. 3).

On top (from the side of arrival of particles) under the cover there are three boards with silicon detecting elements (detectors) 5 in such a way that the detectors are located coaxially: parallel to each other and on the same optical axis. The detectors to increase the noise immunity of the device and the manufacturability of its manufacture and adjustment are mounted on boards; to ensure a through passage of particles under the active area of the detector, a hole is made on each board. The device uses silicon semiconductor flight detectors 300 μm thick with a square active area 1 x 1 cm in size. Bronze rings 3 are installed between the boards above the detectors, which provide passive protection of the device from lateral passage of particles. The protective bronze ring between the detector installed on the first board and the front wall serves as a collimator of the radiation flux (item 3 in Fig. 3). Amplifier and signal shaper assemblies are located on the boards close to the detectors, ensuring the conversion of the signal recorded by the detector into a voltage pulse. Also on the boards are electronic nodes that provide the formation of the bias voltage of the detector. Areas for placing electronics assemblies on the boards are shown in pos. 4. Each functional unit of the electronics is covered with a metal shield. The pulses generated by the electronics are transmitted through the internal connectors (item 7 in Fig. 1) to the fourth board - digital signal processing 2.

The digital signal processing board is located behind (under) the detector boards. It contains a microcontroller, flash memory, and an external interface driver microcircuit. This mutual arrangement of the boards also provides additional passive protection for the most exposed to radiation microcircuits of the digital processing board.

The viewing angle of the claimed spectrometer is determined by its assembly geometry (in particular, the gap, the distance between adjacent boards with detectors) and within the general geometry of the device can be changed from 30 to 45 degrees (with a decrease in the distance between the boards, the viewing angle increases). This setting is preliminary, there is no possibility of changing the viewing angle during device operation.

The claimed device works as follows:

Silicon detectors convert the energy of charged particles hitting the detector element into an electrical charge, which is amplified and converted into a voltage pulse at the amplifier and signal conditioner assembly. This pulse signal is fed to an amplitude selector (discriminator). At the output of the discriminator, a digital signal is generated that corresponds to one of the tuned energy channels of the detector. The received signal is transmitted to the digital signal processing board, in which signals from all three detectors are analyzed and stored.

An example of an amplified signal at the output of the amplifier and signal conditioner assembly is shown in FIG. 2. Charge collection time corresponds to the graph pos.8 (10 μs). The amplified signal (pos. 9) determines the amplitude of the signal in the amplitude selector. The amplitude of the signal at position 9 on the graph is 170 mV. Pos. 10 in the graph for comparison shows the complete collection of the charge in the detector.

The basis of the device (Fig. 1, Fig. 3) is made up of coaxially located pass-through silicon detecting elements (Fig. 5, Fig. 1), covered with passive protection in the form of bronze rings (Fig. 3, Fig. 1). Specific energy losses of a charged particle passing through them depend on the ratio of the charge to the mass of the particle, thus, according to the ratio of particle energy losses in the detectors, the particles are separated by type. The signal amplified in the amplifier and shaper unit is formed in shape and duration, then enters the discriminators, which select the signals by amplitude and form the corresponding voltage pulses. Pulses from the driver unit of each detector board are fed to the counting (digital) inputs of the microcontroller on the digital signal processing board.

Signals from different detectors arriving at the input of the device at the same time refer to one particle that has passed through several (2 or 3) detecting elements.

The digital signal processing board uses the ratio of signals from different detectors to determine the type of particle and its energy (up to the configured energy channel). The received information is written into memory for subsequent sending to the control device of the spacecraft.

The dense arrangement of the electronics of the device and the use of digital electronics controlled by a microcontroller made it possible to double the signal-to-noise ratio in the analog path of the detectors with a multiple decrease in the weight and size characteristics of the device in comparison with the prototype, and also provide the ability to adjust the parameters (except for the input aperture and viewing angle of the device, determined by geometry of the structure) during operation of the device. Can be customized:

- detector bias voltage,

- discriminator thresholds,

- settings of energy channels,

- duration of signal accumulation,

- parameters of interaction of the device with the spacecraft.

Table 1. Specifications of the spectrometer

Parameter Value Measured electron energy range 0.1 ... 10 MeV Measured proton energies range 1 ... 100 MeV Range of measured energies of α-particles > 1 MeV Detector field of view 30 ... 45 °

An example of the implementation of a utility model

The device described above is manufactured and configured for use as part of the payload on spacecraft of the CubeSat type (cubesat) with a form factor of 1U or more. The device includes three boards with silicon transient detectors of 300 µm, located with a gap of 10 ... 22 mm from each other. The optical circuit is protected by 8 mm thick bronze rings inserted between the detector boards. The digital signal processing board is based on the STM32L432 microcontroller.

The device is resistant to external influences at the stage of launching a spacecraft and orbital operation, namely: mechanical loads at the stage of launching, changes in external pressure at the stage of launching, operating temperatures on an ultra-small spacecraft in an unpressurized design, and ionizing radiation of natural space from outer space.

Claims (3)

1. A universal semiconductor spectrometer for the detection of corpuscular cosmic radiation, characterized in that it includes an assembly of four printed circuit boards located under each other with a gap, with ends installed between two walls, while each of the first three boards contains a semiconductor detector equipped with a passive protection device , and an amplifier and signal shaper assembly located close to the detector, and the fourth board is a digital signal processing board, on which a microcontroller, a flash memory device and an external interface driver chip are located, while the detectors of all three boards are located coaxially, and from the side On the first board, the device is closed by a cover with an opening for the flow of charged particles. 2. The spectrometer according to claim 1, characterized in that the semiconductor detector is a silicon semiconductor detector 300 μm thick with a square active region 1 x 1 cm in size. 3. The spectrometer according to claim 1, characterized in that the device for passive protection of the detectors is made in the form of a bronze ring installed in the gap between the corresponding printed circuit boards.

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