New Algorithm for Upgrading of Portal Radiation Monitors with Plastic Detectors. Part 3. Description of the Algorithm

New algorithm is described in the third part of the paper. It uses method of energy windows and is based on iterative scheme. Values of smoothing and thresholds are optimized in each energy window and time step during of movement of transport through control zone. Some parameters of monitor which are measured on the place of its installation or manufacturing are used as input information.

New Algorithm for Upgrading of Portal Radiation Monitors with Plastic Detectors Part 2. Optimization of Values of Alarming Threshold and Smoothing

The way of improving of traditional algorithm for portal radiation monitors with plastic detectors by optimization of values of alarming threshold and smoothing is discussed in the second part of the article. As the result of such optimization the probability of detection of radioactive sources may be significantly increased and probability of false alarms decreased as well.

A Simplified Algorithm for Count Rate Processing in Radiation Monitors That Address Statistical Fluctuations and Spurious Counts

While processing the signals from radiation detectors, for finding the true mean-count-rate, algorithms with hybrid pulse collection methodology have been proposed and used over the years. An algorithm based on this technique with a new methodology of adoption and implementation including spurious rejection is proposed here. It enables a specified and controllable error when the mean-count-rate remains within certain predefined limits from its true value. Effort is made to optimize the response time of prediction at low count rates preserving the optimum possible relative-standard-deviation (RSD). Chi-squared test is utilized for verifying the counting system to check if the observed fluctuations are consistent with the expected statistical fluctuations. A C-program code has been developed to test the algorithm. An observed set of detector outputs are given as input to the program and the corresponding Output is analyzed. A comparative study between the proposed method and floating-mean method is presented for the same set of observations. A typical short-lived high voltage (HV) induced spurious noise pattern is fed as input to the program verifying limited-spurious rejection capability of the algorithm. An embedded C program was written for microcontroller implementation of the algorithm. Case-study of a neutron roentgen equivalent man (REM) counter is presented for evaluating response time for various ranges of operation with calculation of RSD at these ranges. This general-purpose algorithm can enhance the read-out accuracy of radiation monitors used for radiation safety applications.

New Algorithm for Upgrading of Portal Radiation Monitors with Plastic Detectors

The new algorithm for portal radiation monitors with plastic detectors is discussed in the paper. It is based on optimization of the value of smoothing for count rate profiles, alarming thresholds and so called energy windows. Implementation of this algorithm provides increasing of probability of detection of the radioactive sources including those which are masked by NORM under suppression of natural background. The verification of radioactive sources and NORM on the base of analysis of count rate profiles for point and distributed sources is discussed in the first part.

Readying CERN for connected device era

Whether you consider “IoT” as a real thing or a buzzword, there’s no doubt that connected devices, data analysis and automation are transforming industry. CERN is no exception: a network of LoRa-based radiation monitors has recently been deployed and there is a growing interest in the advantages connected devices could bring—to accelerator operations just as much as to building management. Connected devices bring risks as well as advantages, however, and the last thing any business needs is an unsafe, uncoordinated and unmanaged sensor environment. To support the deployment of the LoRa-based radiation sensors, CERN has established both a Low Power Wireless Area Network (LPWAN) to complement the existing wired and wireless networks and a service infrastructure to manage the provisioning, orchestration, data transfer, security and operation for connected devices.

COMPARATIVE STUDY ON PERFORMANCE OF VARIOUS ENVIRONMENTAL RADIATION MONITORS

After the Fukushima Daiichi Nuclear Power Plant accident, the radiation dose for first responders was not evaluated accurately due to lack of the monitoring data. It has been important to evaluate a radiation dose for workers in emergency response at a nuclear accident. In this study, a new device which can evaluate both of external and internal exposure doses was developed and the performance of various environmental radiation monitors including commercially available monitors were tested and compared from the viewpoint of an environmental monitoring at emergency situation. Background counts of the monitors and the ambient dose equivalent rate were measured in Fukushima Prefecture. The detection limit for beta particles was evaluated by the method of ISO11929. The sensitivity for gamma-rays of the dust monitor using a ZnS(Ag) and a plastic scintillator was high, but that of the external exposure monitor using a silicon photodiode with CsI(Tl) crystal was relatively low. The detection limit ranged 190–280 Bq m−3 at 100 μSv h−1, exceeding the detection limit of 100 Bq m−3 in the minimum requirement by the National Regulation Authority in Japan. Use of the shielding with lead is necessary to achieve the minimum requirement. These results indicate that the dust monitor using a ZnS(Ag) scintillator and a plastic scintillator is suitable for the external exposure monitor and the developed internal exposure monitor is for the internal exposure monitor at emergency situation among the evaluated monitors. In the future study, the counting efficiency, the relative uncertainty and the performance of the detection for alpha particles will be evaluated, and it will be considered which type of a monitor is suitable after taking the portability into account.