DO-RA Module Field of the Invention

The invention is related to the ionizing radiation measurement area, particularly, to the devices in which silicon-based PIN diode is used as ionizing radiation source is used. Due to the silicon detectors such devices have rather a high sensitivity; simultaneously they operate at room temperature. The silicon detectors have found a wide application in both household and industrial dosimeters- radiometers.

Prior Art

In the present-day devices with the dosimeter/radiometer function PIN diodes are used as the ionizing radiation sources for the conversion of the charge generated in the silicon detector under the impact of the ionizing radiation during the particle transit into proportional voltage for which purpose the charge amplifier is used (charge-sensitive amplifier: CSA) with the conversion factor of about 1 V/pC with the response rate of about 1 μβεϋ. For the further signal amplification a voltage amplifier shall be used where the total voltage gain factor is about 10 to the power of 5. In these conditions the device detecting the ionizing radiation becomes sensitive to various electromagnetic noises. This is particularly pronounced in case of the device operation near powerful electromagnetic radiation sources, such as smartphones. Besides, the silicon ionizing radiation detector itself generates the charge during the mechanical effects like impacts and vibrations.

These factors result in the worse accuracy of the ionizing radiation measurements through an increased number of spurious impulses caused by different interference.

In particular, the problem of electromagnetic interference is solved by shielding the ionizing radiation of the silicon ionizing radiation detector combined with the charge-sensitive amplifier (CSA), as well as by using filters and optimum positioning of the electrical elements and rational wiring of the printed circuit board. In this case it is a lot more difficult to remove the interference resulting from the mechanical impact on the ionizing radiation detector. The use of the detector mechanical protection increases overall dimensions of the device which is not admissible for compact built-in devices applied for measuring the ionizing radiation exact parameters.

Semiconductor modular radiation dosimeter/radiometer built into the radio device and connected with the amplifier and interface unit the output of which is connected to the processor providing the function of generating acoustic and visual signals of the B dosimeter and radiometer using the acoustic and visual alarm facilities and a monitor is known (RU 109625).

A compact (built-in) design ionizing radiation dosimeter/radiometer is known, it includes an ionization detector represented as a p-i-n diode in which in a low-alloy semiconductor silicon high-alloy p- and n-areas are created as well as control and data transmission interface, a calibrating device, a voltage converter and an integrated circuit, including a charge-sensitive amplifier, a shaping amplifier, spectrometer based on the amplitude-digital converter and comparators, and a microprocessor connected with the control and data transmission interface which provides the function of connection to the mobile device information and power- supply buses, hereby a calibrator and voltage converter connected with the ionization detector connected to the charge-sensitive amplified are connected to the microprocessor. The dosimeter/radiometer has a compact case and is made with the function of the fast installation into a mobile communicator device from the following group: a smartphone, a tablet PC, a laptop and is equipped with independent power-supplies, hereby the microcircuit is made without case. The dosimeter/radiometer includes a successive approximation ADC, a set of threshold synchronization comparators and peak detectors. The dosimeter/radiometer is equipped with the wireless communication interface connected to the microprocessor; the interface belongs to the following group: Bluetooth or hybrid Bluetooth or Bluetooth Low Energy, Near Field Communication (NFC) (RU 145480, prototype).

Disadvantage of the known dosimeters/radiometers is low accuracy due to the noise resulting from the mechanical impact. The interference during the mechanical impact onto the detector is determined by elastic oscillations of the detector and is a periodic signal whereas the signal from the particles is a single impulse.

Summary of the Invention

The technical task of this invention is the development of an efficient dosimeter/radiometer represented as a universal compact module built into different types of electronic devices with extended applicability of these solutions into modern household appliances.

The technical result ensuring the solution of the task set consists in the accuracy improvement due to the segregation and record of the signals resulting from the external physical factors, particularly, electromagnetic and/or vibration mechanical impact, determination of their amplitude and oscillation period as well as digital filtration to eliminate these signals from the impulses to be recorded. The mechanical impact noise elimination in the device claimed is implemented in a holistic manner on software and hardware levels without applying mechanical protection of the silicon ionizing radiation detector itself. By and large, the detector reduced sensitivity to external mechanical impact and improved noise resistance to the external physical factors such as vibration, man-caused and natural electromagnetic oscillations.

The essence of the invention consists in the fact that the modular dosimeter/radiometer contains at least one silicon ionizing radiation detector, a voltage converter the output of which is connected with the charge amplifier input the output of which is connected with the shaping amplifier input while the latter's output is connected with the device for the data evaluation and calculation of the time interval between the impulses and the segregation of the signals received during the particle transit and mechanical impact onto the ionizing radiation detector, hereby the output of the this evaluation and calculation device is connected to the information device via an interface.

Hereby the microprocessor output is connected with the information device using an acceptable lower-level protocol - via an interface from the following group: I2C, RS485, RS232, CAN 2.0, USB.

In the particular cases of the implementation the dosimeter/radiometer is made with one radiation detector and the device for the readings evaluation and between- the-impulse time interval calculation and segregation of the signals received during the particle transit and during the mechanical impact is made as the main and auxiliary comparators and a microprocessor, hereby the outputs of the shaping amplifier are connected with the inputs of the main and auxiliary comparators with their respective outputs connected with the first and the second inputs of the microprocessor the output of which is connected with the information device via an interface, hereby the microprocessor is provided with the function of the impulse record from the main and auxiliary comparators, calculation of the time interval between the pulses and determination of the comparator actuation sequence, hereby the reference level of the signal from the main comparator is set based on the condition of the minimum level of the signal during the particle transit while the reference level of the auxiliary comparator is based on the condition of the noise level in case of the mechanical impact on the ionization radiation detector.

In other implementation cases the dosimeter/radiometer is made with two radiation detectors connected in parallel, two shaping amplifiers and two charge amplifiers, the output of each of them is connected with the input of one of the shaping amplifiers while the device for the data evaluation and calculation of the time interval between the impulses and the segregation of the signals received during the particle transit and mechanical impact is made as two adjustable comparators connected in parallel to the outputs of the shaping amplifiers above, "AND" logic element and "exclusive OR" logic element, one of the inputs of each of the logic elements is connected to the output of one of the comparators and the outputs of both the logical elements are via an interface connected to the information device.

Preferably, the dosimeter/radiometer is equipped with an adjustable reference voltage sources connected to both the comparators provided with the function of setting to the reference level of the signal (record threshold) for each of the comparators

Preferably the radiation detector is provided with the function of measurement of alpha, beta, gamma and neutron radiation as well as solar radiation.

Preferably, the dosimeter/radiometer is provided with the function of fast installation into a mobile information communicator device (master device) from the following group: smartphone, tablet PC. Short description of drawings

Fig.l shows the block diagram of the modular dosimeter/radiometer with the microprocessor, Fig. 2 shows block diagram of the modular dosimeter/radiometer with logical elements.

Detailed Description of the Invention

The modular dosimeter/radiometer includes at least one silicon ionizing radiation detector (sensor) 1, supply voltage converter 8 the output of which is connected with the input of the said detector 1 , the output of which is connected with the input of the shaping amplifier 3 and the output of the latter is connected with the device for the data evaluation and calculation of the time interval between the impulses and the segregation of the signals received during the particle transit and mechanical impact onto the dosimeter/radiometer (detector 1) _^ hereby the output of the this evaluation and calculation device is via interface 7 connected with the information (master) device (not shown).

Hereby the dosimeter/radiometer is connected with the information device via an interface from the following group: I2C, RS485, RS232, CAN 2.0, USB. Power- supply unit 8 provides independent high-voltage supply of sensor(s) 1.

Dosimeter/radiometer as per Fig. 1 is made with one radiation detector 1 and the device for the data evaluation and calculation of the time interval between the impulses and the segregation of the signals received during the particle transit and mechanical impact onto the dosimeter/radiometer (detector 1) is made as the main and auxiliary comparators 4, 5 and microprocessor 6. Hereby the outputs of the shaping amplifier 3 are connected with the inputs of the main and auxiliary comparators 4, 5 with their outputs connected with the first and the second digital inputs of microprocessor 6, the output of which is via interface 7 connected with the information device. Microprocessor 6 is provided with the function of recording the impulses from the main and auxiliary comparators, calculation of the time interval between the impulses and determination of the actuation sequence of comparators 4, 5. Hereby the reference level of the main comparator 4 is set based on the condition of the minimum signal level during the particle transit and the reference level of the auxiliary comparator 5 is based on the condition of the noise level in case of the mechanical impact onto the ionizing radiation detector 1. The dosimeter/radiometer design takes all the actions possible to shield the silicon sensor 1 and input circuits of the read-out electronic devices 2-7 from the electromagnetic impact resulting from the external noise sources, like mobile phones, microwave ovens, radio-equipment. Moreover, the sensor 1 and the device itself are made in vibration-damping design to mitigate the effect of the mechanical impacts onto the dosimeter. In this case the built-in microprocessor 6 provides the analysis of the shaper, amplitudes and durations of the signals and makes the "decision" of the signal nature: radiation effect, vibration or electromagnetic pickup.

The dosimeter/radiometer as per Fig. 2 is made with two ionizing radiation detectors 1 connected in parallel, with two shaping amplifiers 3 and with two charge amplifiers 2, the output of each of them is connected with the input of one of the shaping amplifiers 3, and the device for the data evaluation and calculation of the time interval between the impulses and the segregation of the signals received during the particle transit and mechanical impact onto the dosimeter/radiometer (detectors 1) is made as two adjustable comparators 4, 5 connected in parallel to the outputs of the two shaping amplifiers 3 above, as well as "AND" logic element 10 and "exclusive OR" logic element 9, one of the inputs of each of the logic elements 9, 10 is connected to the output of one of the comparators 4, 5, and the outputs of both the logic elements 9, 10 are connected via interface 7 with the information device.

The two detectors 1 may be essentially identically implemented as a single multi-channel sensor.

Preferably the dosimeter/radiometer as per Fig. 2 is equipped with an adjustable reference voltage source 1 1 connected to both the comparators 4, 5 and provided with the function of setting the signal reference level (record threshold) for each of the comparators 4 and 5.

Preferably the radiation detector is provided with the function of measurement of alpha, beta, gamma and neutron radiation as well as solar radiation.

Preferably, the dosimeter/radiometer is provided with the function of fast installation into a mobile information communicator device (master device) from the following group: smartphone, tablet PC.

Modular Dosimeter-Radiometer with Low-Level Protocols (DO-RA Module) is operated as follows. Within the master information device from the following group: smartphone, tablet PC, the modular dosimeter/radiometer claimed is power-supplied from this device's power-supply facilities.

In the diagram in Fig. 1 the signal from the radiation sensor 1 comes to the input of the charge amplifier 2 converting the charge generated by the radiation sensor 1 into the voltage.

The signal from the charge amplifier 2 comes to the input of shaping amplifier 3 which reduces it to the shape required for the operation of comparators 4 and 5. The main comparator 4 converts the signal from the shaping amplifier 3 into a logical signal routed to the microprocessor 6 digital input. The reference level of the comparator 4 signal shall be selected based on the minimum signal level during the particle transit. The auxiliary comparator 5 also converts the signal from the shaping amplifier 3 into a logical signal coming to the microprocessor 6 digital input. The reference level of the comparator 5 shall be selected based on the noise level during the mechanical impact onto the ionizing radiation detector 1. The microprocessor 6 counts the number of pulses over a certain time and prepares the data processed for their further transmission via the preset interface 7. Microprocessor 6 also records periodic actuations of the comparators 4 and 5, time interval between the pulses of the comparator 4 and comparator 5 as well as the actuations sequence of the comparators 4 and 5.

The data transfer to the master device into which the dosimeter-radiometer module with the ionizing radiation detector 1 is built shall be performed via the interface 7 selected I2C or RS485, RS232, CAN 2.0, USB.

Therefore, recording the signals from the two comparators 4 and 5, it is possible to record a periodic signal from the mechanical impact onto the radiation sensor and eliminate it from the calculation of the determination of the ionizing radiation level (dose rate) and ultimately - the accumulated ionizing radiation dose.

In the diagram as per Fig. 2 the signal from each radiation sensor 1 is routed to the input of the relevant charge amplifier 2 converting the charge generated by the radiation sensor 1 into the voltage.

The signal from the output of each charge amplifier 2 is coming to the input of the relevant shaping amplifier 3 which reduces it to the shape required for the operation of comparators 4, and the reference voltage source 5 determines the record threshold and is adjustable.

The reference level of the signal from one comparator 4 is selected based on the minimum level of the signal during the particle transit. The reference level of the other comparator 5 is selected based on the noise level in case of the mechanical impact onto the ionizing radiation detector 1.

Each of the comparators 4, 5 converts the signal from the shaping amplifier into the logic signal routed to the inputs of logic elements "AND" 10 and "Exclusive OR" 9.

The data transfer to the master device into which the dosimeter-radiometer module with the ionizing radiation detector 1 is built shall be performed via the interface 7 selected I2C or RS485, RS232, CAN 2.0, USB.

A signal from the radiating impact at the reasonable dose power levels with the probability of 0.999999 may occur in one channel only (the dose power 1000-fold increase will reduce this value to 0.999), whereas the electromagnetic pickup and vibration effect will induce the signal similarly in both channels. Therefore, addition of two extremely simple logical elements "exclusive OR" 9 and "AND" 10 to the two-channel system will enable easy "sorting out" of the radiation effect and noise, both mechanical and electric. The potential use of even larger number of channels and "majority" logic diagrams enables substantial improvement of signal filtration quality without using a built-in microcontroller.

In case of the implementation of the diagram as per Fig. 2 it is necessary to use two identical sensors 1 or a single-chip multi-channel (two or more) sensor 1 and the respective number of similar read-out channels. It will somewhat complicate the read-out electronic devices but substantially reduce the demand in the microprocessor computing power for the device as per Fig. 2 in general.

Therefore, a multi -channel sensor 1 and several logic elements 9, 10 provide the signal digital filtration from pickups and mechanical impact.

In case of the implementation of the modular dosimeter/radiometer for the measurement of the ionizing radiation, power-supply elements and their charger are eliminated. As a result of this technical solution implementation an improved measurement accuracy is attained at the expense of the segregation and record of the signals due to the external physical factors, particularly, electromagnetic and/or vibration mechanical impact, determination of their oscillation amplitude and period as well as digital filtration to eliminate these signals from the count of the pulses to be accounted for. The elimination of the noise due to the mechanical impact in the device claimed is implemented on the software and hardware level, without applying mechanical protection. In general, the detector reduced sensitivity to external mechanical impacts and improved resistance to the noise from external physical factors like vibration, man-caused and natural electromagnetic oscillations take place.

Industrial Applications

The present invention is embodied with multipurpose equipment extensively employed by the industry.