Development of 222Rn Emanation Sources with Integrated Quasi 2π Active Monitoring

In this work, a novel approach for the standardization of low-level 222Rn emanation is presented. The technique is based on the integration of a 222Rn source, directly, with an α-particle detector, which allows the residual 222Rn to be continuously monitored. Preparation of the device entails thermal physical vapor deposition of 226RaCl2 directly onto the surface of a commercially available ion implanted Si-diode detector, resulting in a thin-layer geometry. This enables continuous collection of well resolved α-particle spectra of the nuclei, decaying within the deposited layer, with a detection efficiency of approximately 0.5 in a quasi 2π geometry. The continuously sampled α-particle spectra are used to derive the emanation by statistical inversion. It is possible to achieve this with high temporal resolution due to the small background and the high counting efficiency of the presented technique. The emanation derived in this way exhibits a dependence on the relative humidity of up to 15% in the range from 20% rH to 90% rH. Traceability to the SI is provided by employing defined solid-angle α-particle spectrometry to characterize the counting efficiency of the modified detectors. The presented technique is demonstrated to apply to a range covering the release of at least 1 to 210 222Rn atoms per second, and it results in SI-traceable emanation values with a combined standard uncertainty not exceeding 2%. This provides a pathway for the realization of reference atmospheres covering typical environmental 222Rn levels and thus drastically improves the realization and the dissemination of the derived unit of the activity concentration concerning 222Rn in air.

Towards multipixel THz Schottky diode detector with a single RF output line

We propose the design of a dual-pixel array of Schottky diodes. Each diode is fixed between the bow-tie antenna arms on top of a SI-GaAs membrane acting as a waveguide backshort for efficient coupling of the antenna to the feedline of high-directivity horn. The detector utilizes a single RF output line: microwave reflectometer is used for the readout. The pixels are equipped with dual-mode resonator filters to eliminate the cross-talk. We evaluate the design proposed via numerical simulation and performance tests of the array subunits: NEP of 300 pW/Hz0.5 and dynamic range of 24 dB are demonstrated at 137.5 GHz.

Development of measurement methods and dose evaluating algorithms for electronic personal dosimeter

For personal radiation dose monitoring, electronic personal dosimeters (EPD), also known as active personal dosimeter (APD), using silicon diode detector have the advantage capability of measuring and displaying directly the exposure results of gamma, beta and neutron radiations in real time. They are mainly considered as good complement to passive dosimeters to satisfy ALARA principle in the radiation protection. In this paper, the meansurement methods and algorithms for evaluating personal dose equivalents such as Hp(10) and Hp(0.07) from air-kerma are studied and developed in two directions: the first, named energy correction method based on incident energy determined by the ratio of two detector responses with the different filter configurations; the second new method is carried out in the way that matching the shape of a detector’s energy response curve to the kerma-to-personal dose equivalent conversion function provides an approximate means of determining the dose equivalent without the need to resolve the actual incident energies. The algorithm has also been experimentally verified at Secondary Standards Dosimetry Laboratory (SSDL) of INST by the beam of radiation defined in ISO 4037-1. The obtained results of personal dose equivalents with errors almost less than 30% in energy range from 20 keV to 1.5 MeV are partially met the EPD design requirements according to the IEC 61526 Standard. The work and results of described in this paper are important basics for design and construction of completed electronic personal dosimeter.

Intrinsic challenges in x-ray spectrometry instrumentation with CdTe diode detector

The X-ray spectrometry is subject to a diversity of problems that distort the measured beam. To observe them, spectra from N20, N25, N30, N60, N80, and N100 radiation qualities were obtained and evaluated their non-correction impact in the values of mean energy when compared with the requirements on ISO 4037-1 standard. The error percentages calculated were 2%, 2%, 2%, 11%, 9%, and 6%, respectively, related to partial energy deposition, efficiency loss, and charge trapping. These results suggest the need for correction of measured spectra, mainly for voltages higher than 30 kV.

Design of Two Channel Infusion Pump Analyzer Using Photo Diode Detector

In the medical world, patient safety is a top priority. The large number of workloads and the frequency of using the devices in the long run will affect the accuracy and accuracy of the tool. If the flow rate and volume of the syringe pump or infusion pump given to the patient are not controlled (overdose or the fluid flow rate is too high) it can cause hypertension, heart failure or pulmonary edema. Therefore, it is necessary to have a calibration, which is an application activity to determine the correctness of the designation of the measuring instrument or measuring material. The purpose of this research is to make a two channel infusion device analyzer using a photodiode sensor. The contribution of this research is that the system can display three calibration results in one measurement at the same setting and can calibrate 2 tools simultaneously. The design of the module is in the form of an infrared photodiode sensor for reading the flowrate value. This study uses an infrared photodiode sensor for channels 1 and 2 installed in the chamber. This study uses a flow rate formula that is applied to the water level system to obtain 3 calibration results. Infrared photodiode sensor will detect the presence of water flowing in the chamber from an infusion or syringe pump. Then the sensor output will be processed by STM32 and 3 calibration results will be displayed on the 20x4 LCD. This tool has an average error value on channel 1 of 3.50% and on channel 2 of 3.39%. It can be concluded that the whole system can work well, the placement and distance between the infrared photodiodes also affects the sensor readings

Building a VME spectrometer and testing Si PIN diode detector: a feasibility study for the first nuclear astrophysical experiments using a pelletron

This work presents the logical design, connections between NIM and VME elec­tronic modules, and the data acquisition programming to build a complete detector readout system. The test experiments were carried out with commercial silicon PIN diode S3590-09 bare detectors bombarded by charged particles from a 241Am α-source and Rutherford elastic backscattering (RBS) protons induced by 2.5 MeV proton beam bombarding on an Au-on-glass target, and with a NaI scintillation detector bombarded by gammas from 27Al(p, γ)28Si reaction with proton beam energy of 1.379 MeV. The test showed that the spectrometer operated steadily and its versatility for different kind of detector. The energy resolutions of the Si diodes were less than 0.5% energy of a charged particle, which satisfies the foreseen requirement for the upcoming experiments.