Technical Field

The invention relates to a silicon-based radiation detection device which is used in areas where radiological safety must be ensured, such as in the iron and steel industry, scraps, waste facilities, critical buildings and areas; in various fields of industry, such as irradiation facilities, industrial radiography, radioisotope level meters, thickness gauges, and food controls; in nuclear facilities; in customs controls and many other professional fields, and which enables the detection of naturally occurring radioactive materials (NORM) and technologically enhanced naturally occurring radioactive materials (TENORM).

Prior Art

The correct identification of radioactive materials is a worldwide safety measure. Radiation detection devices are essential for the detection and measurement of radiation sources. The sources in our environment must be removed before they harm human health. Radiation sources, which are highly effective on human health, must be identified in advance.

It can be seen that the Geiger Muller (GM) tube is widely used for radiation detection in the state of the art. Radiation detection devices comprising GM tubes have low efficiency. Radiation detection devices that can measure ionizing radiation (usually comprising a GM tube) cannot measure neutral particles (neutrons). Since the pulse height is independent of the type and energy of the radiation, they cannot make a distinction. They cannot obtain information about the nature of the ionization causing the pulse. GM detectors cannot make a distinction between different types of radiation (alpha, beta, gamma) or between various radiation energies. This is because the size of the avalanche is independent of the primary ionization that generates it. Due to the large avalanche caused by any ionization, a Geiger counter takes a long time (about 1 ms) to recover between successive pulses. Therefore, Geiger counters cannot measure high radiation rates due to the “dead time” of the tube. They also require high supply voltage (low power GM tube 100V-150V, PM tube 1000V). Today, SiPM (silicon photomultiplier tube) has been developed with much higher quantum efficiency. SiPMs are semiconductor photon detectors operating in the Geiger mode and formed by connecting a series of micro avalanche photodiodes in parallel. SiPMs have high quantum efficiency. A SiPM-based radiation detection device can also detect neutral particles with an appropriate scintillator (boron) as opposed to the radiation detection devices comprising GM tubes. It can also characterize mixed sources (alpha, beta, gamma, X-ray, neutron) using a combination of appropriate scintillators. It can measure the energy of neutrons that do not directly cause ionization through secondary ionizations. It is envisaged that using SiPMs could potentially provide a practical solution to long-standing problems that have limited the development of advanced nuclear imaging technology. This will significantly accelerate and expand the progress of research, technology and application development in the field of nuclear imaging.

Customs controls have been identified as the target market within a wide range of application areas. The smuggling of radioactive materials into our country not only causes economic damage, but also makes it difficult to track these materials when they complete their life cycle and become radioactive waste. In particular, radioactive materials used in the medical field are among the most smuggled products. Radioactive materials used for diagnostic and therapeutic purposes should also be tracked after they become waste. Waste that is not properly managed can cause great harm to the environment and living beings.

There is a need to develop new devices to overcome the mentioned disadvantages of the state of the art.

Summary of the Invention

The object of the invention is to manufacture a silicon-based radiation detection device for the detection of naturally occurring radioactive materials (NORM) and technologically enhanced naturally occurring radioactive materials (TENORM).

The device according to the invention can be customized for the user in portable sizes. This provides advantages such as early detection and removal of radioactive materials that threaten human health, especially in residential areas. In addition, modifications can be made on the device according to the type of radiation that the user intends to detect and the most suitable device can be offered to the user according to the working conditions.

The Radiation Detection Device comprises a silicon photomultiplier (SiPM). Since the device is based on semiconductors, it is more immune to magnetic fields than similar devices. It can detect ionizing radiation (alpha, beta, gamma, X-ray, neutron) through the use of appropriate scintillation crystals. The low bias of silicon photomultipliers (SiPM) allows it to be supplied by a low-volume battery pack. In this way, it is produced in sizes that can be easily carried in hand. Thanks to its color TFT display, it can report the type and activity of the detected radioactive radiation to the user. The device comprises rechargeable lithium-ion cells, known as secondary cells. It can be charged via USB. It is presented to the user in an impact-resistant silicone case. Calibration settings can be done easily on the TFT display. USB interface is used for PC data transfer. Thanks to the program interface running on Windows I Linux operating system, transferred data can be reported.

Compared to existing devices (Geiger Muller Counter - 100/150 V), the use of semiconductor material instead of tubes in the device design reduces the supply voltage (35-40V) of the device, thus reducing the battery volume and reducing the device weight.

The disadvantage of low efficiency (20-25%) of Geiger Muller counters is improved by 50% thanks to the Silicon Photomultiplier (SiPM) used in the design of the device.

The distinction between different radioactive radiations (which cannot be achieved in GM tubes) is realized by SiPM.

Non-ionizing radiation (which can be measured by secondary scattering) and neutrons are detected by a boron-doped plastic scintillator used in the device design.

Because of the multiple scintillation crystals used in the device design, detection is possible over a wider range (about 0-10mSv/h) than the energy range that the GM tubes can detect (about 0-5mSv/h).

Fig. 1 is a top perspective general representation of the device according to the invention. of the Reference Numbers in the

For a better understanding of the invention, the corresponding reference numbers in the drawings are given below:

10. Device

1. Plastic scintillator

2. First scintillator crystal (Nal (Tl))

3. Second scintillator crystal (Csl (Tl))

4. Silicone grease

5. Light guide

6. Silicon photomultiplier (SiPM)

Detailed Description of the Invention

The device (10) according to the invention comprises at least one plastic scintillator (1), at least one first scintillator crystal (2), at least one second scintillator crystal (3), at least one silicone grease (4), at least one light guide (5) and at least one silicon photomultiplier (6).

Silicone grease (4) is used to reduce photon losses between the boron-doped plastic scintillator (1) and/or the first scintillator crystal (2) and/or the second scintillator crystal (3) on the top layer and the light guide (5). Said silicone grease (4) is positioned between the boron-doped plastic scintillator (1) and/or the first scintillator crystal (2) and/or the second scintillator crystal (3) and the light guide (5). The thallium-doped second scintillator crystal (3), the first scintillator crystal (2) and the boron-doped plastic scintillator (1) convert radioactive radiation into visible light. A silicon photomultiplier (6) is used to amplify weak light signals. The silicon photomultiplier (6) positioned under the light guide (5) performs this task very well by converting light signals, which typically consist of many photons, into a useful current pulse without adding a large amount of random noise to the signal. The first scintillator crystal (2) and the second scintillator crystal (3) used in this device (10) emit visible light in proportion to the amount of radiation received. The amount of said light is measured with silicon photomultipliers (6) to determine the amount of radiation. Said emitted light is collected by the silicon photomultiplier (6) and converted into voltage pulses. The size of the resulting pulse is proportional to the energy of the radiation.

On the other hand, the device (10) is used for counting and energy distinction at the same time. By changing the Thallium-doped second scintillator crystal (3) and/or the first scintillator crystal (2) and/or the boron-doped plastic scintillators (1) used in the said device (10), it is possible to detect radioactive radiation of different types and energies.

The scintillation crystal detects the scattered radioactive rays and converts them into photons of visible light. The second scintillator crystal Csl (Tl) (3) is used as a scintillator in radiation detectors. However, the device (10) uses the first scintillator crystal Nal (Tl) (2), which, together with its higher intensity, provides a higher stopping power for gamma radiation and thus increases the reaction. Said first scintillator crystal Nal (Tl) (2) provides a good luminous efficiency of 52.000 photons per unit energy of the incident gamma ray. The second scintillator crystal Csl (Tl) (3) perfectly matches the sensitive wavelength ranges of the silicon photomultiplier (6). The boron scintillation crystal to be used detects neutrons. The silicon photomultipliers (6) amplify and convert the weak light output of the Thallium-doped second scintillator crystal (3) and/or the first scintillator crystal (2) and/or the boron-doped plastic scintillators (1) into photoelectrons. However, the weak signals output by the silicon photomultipliers (6) must be amplified for processing. The amplifier circuit amplifies these signals and the analog signal is converted to a digital signal (ADC) for processing the Field Programmable Gate Arrays (FPGA). In this way, the radioactive radiation is characterized from the peaks of each signal.

The device (10) comprises a detection element (Si PM) for converting incoming radiation into electrical signals, a signal processing element (Amplifier) for amplifying and converting the electrical signals into digital signals, a data processing element (FPGA) for converting the digital signals into data, and a display element for displaying the data. With the invention, the energy of ionizing radiation (alpha, beta, gamma, X-ray, neutron (not directly ionizing)) can be measured. It can measure the energy of neutrons that do not directly cause ionization through secondary ionizations.

If the light consists of a pulse from a scintillation crystal, the photoelectrons produced will be a pulse of similar time duration. Since only a few hundred photoelectrons can be involved in a typical pulse, their charge is too small at this point to be used as a suitable electrical signal. The electron multiplexer part in a PM tube provides an efficient collection geometry for photoelectrons and acts as a near-ideal amplifier to substantially increase their number. After amplification through the multiplexer structure, a typical scintillation pulse consists of 107-1010 electrons, which are enough to be used as the charge signal for the original scintillation event. This charge is collected in the anode or output stage of the multiplexer structure.

The first scintillator crystal (2) used in the invention is a Nal (Tl) scintillator, but is not limited to this in practice.

The second scintillator crystal (3) used in the invention is a Csl (Tl) scintillator, but is not limited to this in practice.

Industrial Applicability of the Invention

The invention is a silicon-based radiation detection device (10) which is used in areas where radiological safety must be ensured, such as in the iron and steel industry, scraps, waste facilities, critical buildings and areas; in various fields of industry, such as irradiation facilities, industrial radiography, radioisotope level meters, thickness gauges, and food controls; in nuclear facilities; in customs controls and many other professional fields, and which enables the detection of naturally occurring radioactive materials (NORM) and technologically enhanced naturally occurring radioactive materials (TENORM) and is applicable to industry.

The invention is not limited to the above-mentioned exemplary embodiments, and one skilled in the art can easily come up with different embodiments of the invention. These should be considered within the scope of the protection sought by the claims of the invention.