Dosimeters are called devices that are necessary to measure the power of ionizing radiation. It should also be borne in mind that some models are additionally able to evaluate the effectiveness of the dose. X-ray meters do not belong to dosimeters. The main element of the device is pleasant to consider the detector. In terms of sensitivity, it is quite different. In general, these devices can be divided into professional and domestic modifications.
For the military, special models are used that are designed for harsh conditions of use. In turn, industrial modifications are designed for continuous monitoring of radiation. DIY radiation dosimeters are pretty easy to assemble. However, this applies only to household devices. To make a professional model, it is necessary to study the schemes of these devices.
Household model in 3 minutes
Assembling a dosimeter with your own hands in 3 minutes is quite simple. First of all, take an eggplant with a capacity of at least 1.5 liters. After that, the device will need a single-pole type tester. First, the eggplant must be cut. For this purpose it is better to use a knife. The next step is to install the tester in the tank. Next, to assemble a simple dosimeter with your own hands, a conductor is connected to it.
A capacitor for this purpose will need an open type. A hole for the knitting needle is made in the upper part. It is best to pick it up copper, with a diameter of not more than 1.2 mm. As a result, parts of the eggplant must be fastened with electrical tape. When the tester is turned on, the signal from the spoke is transmitted to the resistor. As a result, the power of ionizing radiation is displayed on the device.
You can make a do-it-yourself dosimeter from a tin can if you prepare a feed-through capacitor and a single-pole tester in advance. In this case, no eggplant is required for the device. At the bottom of the can, you need to make a small hole for the knitting needle. After that, a capacitor is installed in the tank. The resistor, in turn, must be directly connected to the tester. After that, it remains only to fix the spoke in the opening of the can.
Device with a two-wire detector
With a two-wire detector, how to assemble a dosimeter with your own hands? In fact, if you select all the necessary components, then this task is quite feasible. First of all, a container is prepared for the device. As a rule, it is selected plastic type. Its dimensions largely depend on the dimensions of the detector. It should also be borne in mind that a build-in capacitor is required to assemble the model. In turn, three resistors must be prepared.
Next, to make a dosimeter with your own hands, a damper is taken. For a model with a two-wire detector, it is selected only single-channel. It must be installed directly at the capacitor. Rectifiers for dosimeters of this type are only resonant. In turn, expanders are rarely used by specialists. A feed-through capacitor is used directly to measure the effectiveness of the dose. Additionally, note that the damper in the device must be installed behind the detector.
The use of three-wire detectors
How to make a do-it-yourself dosimeter with a three-pass type? It should be noted right away that this task is not easy. Three-pass devices belong to professional modifications and are designed to measure not only the dose efficiency, but also the radiation power. It is only necessary to install the detector after all passage capacitors are fixed in the housing. In this case, the resistors are used only closed type.
In turn, dampers fit single-channel. The extender in this case will require a low frequency. To measure the radiation power, only resonant rectifiers are used. To install them you will need to use a soldering iron. Zener diodes in such devices are used quite rarely. This is due to the fact that the error in their measurements is high. It should also be taken into account that the radiation power parameter directly depends on the type of output resistor. Most often, it is selected electrolytic.
Using Vector Resistors
You can assemble a dosimeter with vector resistors with your own hands (the diagram is shown below) can only be paired with network detectors. Today it is quite difficult to purchase them in a store. It should also be borne in mind that this product nowadays costs a lot compared to other types of detectors. Install resistors only after fixing the feed-through capacitor. In some models, two units are soldered to them. In this case, the negative resistance of the circuit can sometimes reach 30 ohms. In this case, the accuracy of the measurements is significantly affected. Also, the capacitance of capacitors can affect the error of the device. Most often they are selected at 20 pF. All this is enough to provide the model with excellent sensitivity.
Next, to make a dosimeter with your own hands, a rectifier is installed. In this case, it is suitable for the resonance type. However, positional models are also considered by many experts. At this stage, it is very important to calculate the electromagnetic interference parameter. To reduce the environmental impact, many experts recommend installing electrostatic units in the devices. Purchasing them in a store is quite simple. It is also possible to use a low power trigger. However, in this situation, the negative resistance in the dosimeter can increase dramatically. To prevent frequency shifts often, it is more advisable to use the integrated triggers.
The use of integrated resistors
You can make a simple do-it-yourself dosimeter with integrated resistors (the circuit is shown below) very quickly. First of all, this will require picking up a case. In this case, you can use a plastic box. Next, to make a dosimeter with your own hands, you need to install a damper. Most often, it is selected multi-channel type. In turn, single-channel models do not give high accuracy readings.
It should also be noted that many experts recommend the use of counters. As a rule, they are selected binary type. They must be installed directly on the detector. In this case, the capacitors are soldered after the resistors. In total, they will require three units for the dosimeter. The first of them is installed immediately on the detector. Its sensitivity depends largely on the type of expander. The remaining two capacitors are mounted on the outside of the rectifier. To do this, you will have to use a blowtorch.
A simple model on the PP20 transistor
It is not easy to assemble this type of radiation dosimeters with your own hands, however, it should be understood that in this case the detector is suitable only for pulse type. It is necessary to install the transistor on the rectifier. Extenders for these purposes are selected mainly of the analog type. All this is necessary in order to more accurately measure the radiation power. Among other things, it is important to select a high-quality counter for the dosimeter. Most often it is used with a segment indicator. The most common modifications are sold in stores marked K17. LEDs for devices of this type are rarely used. In turn, testers can be installed only low-frequency type. Moreover, their sensitivity is quite low.
Using the transistor PP30
Transistors of this type are usually installed on professional models. Their conductivity is quite good, but they are capable of working with detectors of only a two-wire type. To assemble a dosimeter with your own hands, first of all you need to make a case for the device. After that, it is standardly necessary to select a high-quality capacitor through passage for the dosimeter.
Its minimum capacitance should be at the level of 40 pF. All this is necessary so that the negative resistance in the circuit is maintained at 20 ohms. Frequency shifts in this case can be controlled using a rectifier. To measure the radiation power, a conventional damper is used. Install transistor P30 is possible only after fixing the expander. Emitter zener diodes are often used, however, they do not seem to be suitable for determining the effectiveness of a dose.
Diaphragm Capacitor Model
Membrane-type devices are quite common today. Compared to camp capacitors, they are characterized by reduced sensitivity. In this case, the negative resistance in the circuit is usually not more than 3 ohms. All this suggests that the accuracy of determining the radiation power in such devices is quite high. It should also be borne in mind that the detectors in this case are suitable only for a two-wire type. In general, the models are compact, but the characteristics are quite different. Expanders for such capacitors are suitable for the electrostatic type. In turn, rectifiers are used both analog and resonant.
However, to improve the accuracy of the testimony, many experts advise to dwell on the second option. Triggers for the indicated dosimeters are suitable for medium power. It should also be borne in mind that zener diodes are used in devices quite rarely. At the same time, dampers must be installed with two resistors to increase sensitivity.
Using Broadband Capacitors
Broadband modifications are quite rare today. Sensitivity is not the best. It should also be borne in mind that they are not able to determine the radiation power. Detectors are most often selected three-pass type for devices. Thus, they are quite large in size. Dampers are installed on a wide variety of dosimeters. To improve the accuracy of the readings, multichannel modifications are often used. The frequency of electromagnetic interference in this case depends on the class of rectifier. Many experts purchase them with low bandwidth.
Most often they can be found with the marking MP30. Additionally, modifications of the MP40 class are known. Their input response is quite high, but they are able to withstand a low resistance. Install capacitors on the device only after fixing the detector directly. It should also be noted that three resistors are required for the circuit. The first one should be soldered at the beginning of the chain. In this case, the other two resistors are necessary for the expander.
Low sensitivity dosimeter
Dosimeters of low sensitivity are most often used by the military. To assemble a model of this type, you must first select a high-quality sensor. At the same time, counters are most often used with segment indicators. In turn, capacitors for such modifications are more suitable for the passage type. Resistors, many experts recommend purchasing analog.
All this is necessary in order to increase the sensitivity of the device to the desired level. Triggers in models are most often used with low power. The maximum negative resistance they must withstand at 4 ohms. In this case, the sensor itself must be rated at 5 ohms. The speed of the output signal depends solely on the power of the capacitor. There are no dampers in this type of device.