RU2659717C2 - Semiconductor pixel detector of charged strongly ionized particles (multicharged ions) - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: use: to create a semiconductor pixel detector of highly ionizing charged particles. Summary of the invention consists in that the detector comprises a series connection of a monolithic layer of a high-resistance semiconductor material (sensor) with a solid outer and pixel internal metal electrodes and a recording pixel microcircuit with a gain of at least 80 mV/fKl, the source of the bias voltage is excluded from the detector circuit and a resistor is added which is connected to the external metal electrode of the sensor and the recording circuit.

EFFECT: providing the possibility of simplifying the design of the detector, reducing the weight and power consumption of such equipment, improving the reliability of the detector and the convenience of its operation.

1 cl, 4 dwg

Description

The invention relates to the measurement of nuclear radiation, and in particular to the measurement of charged ions using semiconductor solid-state detectors of ionizing particles.

In modern semiconductor detectors of ionizing particles [1], the response to the fact of particle registration occurs in the form of an electric signal, in contrast to detectors forming a visual image of a particle track (emulsions, Wilson chambers, and bubble chambers).

The sensor material of a semiconductor (Si, GaAs, CdTe, CZT, ...) must satisfy the following requirements: have a sufficiently large resistivity (r> 10 kOhm / cm) and a sufficiently long carrier life resulting from ionization of the sensor substance detected by the particle. Fulfillment of these requirements allows creating an electric field of sufficient magnitude for directed drift of free carriers arising in the sensor’s volume when a particle or gamma quantum passes through it to the electrodes and occurrence, as a result of this, of a current pulse in the voltage supply circuit to the detector electrodes. It must be emphasized that the requirement to create an electric field in the volume of any sensor is one of the fundamental requirements for any detector that generates an electric signal as a response to the fact of registration of a particle in it [1-10].

Known coordinate detectors of ionizing radiation made on silicon. Known silicon detectors contain a working volume of a sensor made of high-resistance material (usually n-type conductivity with a resistivity of 15 kΩ / cm) [1]. Solid metallization is deposited on one surface of the sensor’s working volume; metallization is applied to another in the form of parallel strips (strips) with a given step or a two-dimensional matrix of pixels, each of which is connected to the input of the readout electronics chip. A bias voltage is applied to the described sensor plates.

Known coordinate detectors of ionizing radiation, made on high-resistance gallium arsenide (GaAs: Cr). GaAs: Cr detectors contain the working volume of a high-resistance GaAs: Cr sensor [2] with a resistivity of up to 10 ⁹ Ohm / cm. Solid metallization is deposited on one surface of the sensor’s working volume, and metallization in the form of parallel strips (strips) with a given step or a two-dimensional matrix of pixels, each of which is connected to the input of the readout chip, is deposited on the other. A bias voltage is also applied to the described sensor plates.

The disadvantage of such detectors is that to ensure the operation of all these detectors, a stable power supply with a voltage of tens (for silicon) and hundreds (for GaAs: Cr) volts is required, which significantly complicates the design of the detector and increases its weight.

The closest analogue is the patent of a pixel semiconductor detector of elementary particles "Single-layer semiconductor detector of three-dimensional images (3D)" [10].

The detector consists of a monolithic layer of a high-resistance semiconductor material (sensor) in which charges can arise as a result of the interaction of the particle that will be detected. The sensor has a solid outer and pixel inner metal electrodes. A recording matrix chip with a gain of at least 80 mV / fCl is connected in series with the sensor. A chip of pixel electronics of reading type Timepix, registers the magnitude of the charges formed and drifting under the influence of the applied electric voltage. Each pixel of the Timepix chip is connected to the corresponding pixel on the inner surface of the sensor using the inverted crystal method. A bias voltage is applied to the external and internal metal electrodes of the sensor.

The disadvantage of all these, as well as other known solid-state semiconductor detectors of highly ionizing particles (multiply charged ions) is the need to connect a bias voltage source.

An object of the invention is to eliminate this drawback. No need for a voltage source will significantly simplify the design of the detector, reduce its weight, increase the reliability of the detector and ease of operation.

The solution to the technical problem is that a resistor is added to the detector circuit, which is connected to the external metal electrode of the sensor and the recording microcircuit.

As a result of the combined effect of large energy release (more than 4 MeV) in the sensor from a high-resistance semiconductor and high sensitivity of modern pixel electronics circuits (gain of at least 80 mV / fCl at a low noise level <75 e ^- ), the detector detects the passage of a strongly ionizing particle even at full the absence of bias voltage applied to the sensor electrodes.

An essential feature of the invention is the inclusion of a resistor in the detector circuit, which eliminates the voltage source supplied to the sensor metal electrodes, solves all the technical problems posed and opens up new possibilities for using such detectors in conditions of limited space, power consumption and the need for long-term autonomous operation.

List of figures

FIG. 1 Schematic diagram of a pixel semiconductor detector of elementary particles (prototype).

FIG. 2 Schematic diagram of a semiconductor matrix detector of highly ionizing charged particles (multiply charged ions).

FIG. 3 and 4 Examples of implementation of the proposed detector.

Description of figures:

In FIG. 1 presents a schematic diagram of a pixel semiconductor detector of elementary particles in accordance with the prototype [10], where:

1 - Monolithic layer of high-resistance semiconductor material (sensor);

2 - Solid external metal electrode;

3 - Pixel inner metal electrode;

4 - Recording pixel microcircuit;

5 - Track of a charged particle;

6 - Source of bias voltage;

In FIG. 2 is a schematic diagram of a semiconductor matrix detector of strongly ionizing charged particles (multiply charged ions), where:

1 - Monolithic layer of high-resistance semiconductor material (sensor);

2 - Solid external metal electrode;

3 - Pixel inner metal electrode;

4 - Recording pixel microcircuit;

5 - Track of a charged particle;

7- Resistor;

In FIG. 3 shows an example of the implementation of the proposed detector, namely, the fact of registration of krypton ions (84 Kr) after replacing the power source with a resistance, where:

- On the X axis - the pixel number along the X axis,

- On the y-axis - the pixel number along the y-axis,

- The color scale on the right (E) is the energy recorded in a pixel in relative units.

An example of recording 16 krypton ions (84Kr) with an energy of 240 MeV that passed during a 50 ms exposure in a heavy ion beam at the JINR Laboratory of Nuclear Reactions through a detector with a silicon sensor (300 μm thick) and a Timepix microelectronics chip after replacing the power source with a resistance. The color of the pixel corresponds to the energy recorded in this pixel (relative units) in accordance with the given color scale.

In FIG. Figure 4 shows a more detailed example of the registration of one krypton (84Kr) ion with an energy of 240 MeV in a heavy ion beam at the JINR Laboratory of Nuclear Reactions in a detector with a silicon sensor (300 μm thick) and a Timepix microelectronics chip after replacing the power source with a resistance. The color of a pixel corresponds to the energy recorded in that pixel (rel. Units) in accordance with the given color scale.

- On the X axis - the pixel number along the X axis,

- On the y-axis - the pixel number along the y-axis,

- On the Z axis is the energy (E) recorded in the pixel in relative units.

The invention can be used in nuclear technology on accelerators of heavy nuclei and, especially, when creating installations for registering heavy nuclei in outer space that are little sensitive to the background from relativistic uncharged particles (protons and electrons) and gamma quanta. For installations that are part of spacecraft, the absence of direct voltage sources in such detectors is especially important, which will significantly reduce the weight and energy consumption of such equipment.

Information sources

1. J. Bouchami et al., Fast neutron detection efficiency of ATLAS-MPX detectors for the evaluation of average neutron energy in mixed radiation fields. NIM A 633 (2011) S226-S230.

2. Lukas Tlustos, Georgy Shelkov, Oleg P. Tolbanov. Characterization of a GaAs (Cr) Medipix2 hybrid pixel detector. NIM A 633 (2011) S103-S107.

3. Price V. Registration of nuclear radiation. "Publishing house of foreign literature", Moscow, 1960.

4.L.K.L. Yuan and C. By. Principles and methods of registration of elementary particles. Ed. Foreign Literature, Moscow 1963

5. D. Ritson. Experimental methods in high energy physics. M .: Nauka, 1964.

6. K. Kleinknecht. Particle radiation detectors. M .: World 1994.

7. L. Rossi, P. Fischer, T. Rohe, N. Wermes. Pixel Detectors

Springer ISSN 1611-1052 2006.

8. C. Teyssier, et al., Performance of the Medipix and Timepix devices for the recognition of electron-gamma radiation fields. Nucl.Instrum.Meth. A650 (2011) 92-97,

9. a) X. Llopart, R. Ballabriga, M. Campbell, L. Tlustos, W. Wong - Timepix, a 65k programmable pixel readout chip for arrival time, energy and / or photon counting measurements. NIM A 581 (2007) 485-494,

b) T. Poikela et al., Timepix3: a 65k channel hybrid pixel readout chip with simultaneous toa / tot and sparse readout, Journal of Instrumentation 9 (2014) C05013.

10. US patent US9297912 "Single-layer semiconductor detector of three-dimensional images (3D)" from 03.29.2016.

Claims (1)

A semiconductor pixel detector of highly ionizing charged particles (multiply charged ions), comprising a series connection of a monolithic layer of a high-resistance semiconductor material (sensor) with a continuous external and pixel internal metal electrodes and a recording pixel microcircuit with a gain of at least 80 mV / fCl, characterized in that A resistor is added to the circuit, which is connected to the external metal electrode of the sensor and the recording microcircuit.

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