Dosimeter test: which one to choose?
Household dosimeters manufactured in Russia and other CIS countries occupy a leading position in the world market, so only such devices were selected for the editorial test. They were tested in laboratory conditions (alpha, beta and gamma sources), as well as at one of the sites of radioactive contamination (radium-226, 0.92 μSv / h) and in domestic conditions (potassium fertilizers, welding electrodes with thorium and ionization smoke detectors). For control, we used an Exploranium GR-130 gamma spectrometer. All dosimeters measured the level of gamma radiation (except for soft) within the limits of the certified error, and for other types of radiation the discrepancies were significant. Most of the tested dosimeters use the classic Geiger-Muller counter SBM-20 manufactured by Electrokhimpribor. Alas, its sensitivity leaves much to be desired, and at low levels of radiation, counting lasts several minutes. In dosimeters the size of a watch, an SBM-21 counter is used, which is even less sensitive (about 10 times). More advanced dosimeters use end counters. Our test involved a dosimeter with such a Beta-1 counter manufactured by Consensus, which is approximately two times more sensitive to gamma radiation than SBM-20, but also more expensive.
Radeks RD1503 +
Sensor : SBM-20 without filter. Measurements : overestimates at low gamma radiation energies and mixed gamma-beta radiation. On some sources, the device went off scale - the upper limit of the range is the smallest of all participants in the test. The natural background is overstated by about one and a half times. It is not suitable for searching for small foci of infection due to the low sensitivity of the sensor. Conclusions : the device has a user-friendly interface; only the frequent unmotivated restart of the measurement cycle upsets, which is why getting accurate results can be delayed.
Sensor : 2xSBM-20 without filters. Measurements : overestimates when exposed to soft gamma radiation and mixed gamma-beta radiation. It overestimates the natural background by about one and a half times. To search for small foci of infection is not ideal, but suitable: two sensors accelerate its response to changes in radiation levels. Conclusions: nice interface plus twice the speed of measurements. In addition, this device is much less prone to unmotivated restart measurements.
Sensor : SBM-20 without filter. Measurements : overestimates when exposed to soft gamma radiation and mixed gamma-beta radiation. It overestimates the natural background by about one and a half times. It is not suitable for searching for small foci of infection due to the low sensitivity of the sensor. Conclusions: very compact, lightweight, with a color display and the ability to connect to a computer via USB. The color palette and fonts do not always contribute to good readability. Displays a qualitative assessment of the background level and a diagram of the change in readings over time. If the manufacturer updates the firmware, removing completely unnecessary animation on startup and shutting down, optimizes colors and fonts for better readability, you get one of the best household appliances.
Sensor : SBM-20 with a filter. Measurements : in general, the readings do not go beyond the passport error. Thanks to the removable filter, Terra-P allows you to make rough measurements of the flux density of hard beta radiation. The natural background is overstated by about one and a half times. It is not suitable for searching for small foci of infection due to the low sensitivity of the sensor. Conclusions : the device looks adapted for the field, and not just for gentle home use. The filter greatly contributes to the accuracy and convenience of measurements. Unfortunately, the device does not remember the settings of the alarm threshold and resets it to 0.3 μSv / h.
Sensor: 2xSBM-20 with filters . Measurements : very accurately measures radiation from cesium-137, but soft gamma radiation overestimates almost one and a half times. A separate mode for measuring beta-particle flux density allows you to not use any approximate conversion factors. The natural background is about 1.5 times as high. It is decidedly unsuitable for searching for foci of infection, since it is not able to take measurements continuously and does not voice the particle registration. Conclusions: the harsh legacy of the Soviet past. This device can do nothing but count the number of pulses in a given time. The manual offers to carry out all the mathematical processing without hesitation to the user, using a pencil and paper. On the other hand, it is a device registered in the registry that undergoes individual testing, but at the same time stands as a regular household dosimeter.
Sensor : SBM-20 for measuring high, medium and high levels of radiation, SI3BG for measuring huge levels of radiation. Equipped with a filter and a control source for strontium-90. Measurements : at less than 0.5 μSv / h, the needle oscillates slowly, making measurements difficult. At high levels of radiation, the readings of the device are quite stable in a wide range of gamma radiation energies. The low sensitivity of the sensor is partially compensated by the placement on a sliding rod, so that the search for radiation spots using the DP-5 is easier than with most other test participants. Conclusions: the military, and hence the even more severe legacy of the Soviet past. In some cases, such a device can be obtained for a symbolic price. But it is rather a subject for a collection or props.
Sensor : SBM-21 without filter. Measurements : the soft gamma radiation dosimeter overestimates approximately twice. It is not sensitive to beta radiation. Overestimates the natural level of radiation by about a quarter. Local contamination can only be detected by chance - the device responds to changes in radiation levels very slowly. Conclusions: the inhibited reaction to changes in dose rate is not very pleasing.
SNIIP Aunis MKS-01SA1M
Sensor : Beta-1 end counter, movable filter. Measurements : the only test participant who was able to adequately measure the flux density of beta particles from cesium-137 and measure the flux density of alpha particles. Overestimates the natural level of radiation by about one and a half times. Thanks to the sensor, the most sensitive to gamma and especially beta radiation, it is the most suitable device of all tested for the search for radioactive spots. Conclusions: by far the best device. A very convenient system for indicating relative statistical error with continuous refinement of the result.The article "Measure the dose" was published in the journal "Popular Mechanics" (No. 1, January 2012).