New Free-Release and Sorting Monitors Developed for NPP A-1 Decommissioning, Slovakia

2011 ◽  
Author(s):  
Ondrej Sla´vik ◽  
Alojz Slaninka ◽  
Martin Lisˇtjak ◽  
Kamil Krava´rik ◽  
Igor Pe´ly
Keyword(s):  
Detection Efficiency ◽  
Metrological Certification ◽  
Acquisition Time ◽  
Semiconductor Detectors ◽  
Accuracy Class ◽  
Counting Geometry ◽  
Prototype Test ◽  
Uncertainty Of Measurements ◽  
Indication System ◽  
Calculation Code

A pilot free-release monitoring post with a 600 L container monitor was developed and metrological tested within the 2nd stage of NPP A1 decommissioning project. In order to reduce the volume of contaminated soil monitoring a conceptual design of fast sorting loader shovel monitor (loader’s spoon) was proposed and tested within the project as well. The free-release monitoring post makes use of a pair of electrically cooled lead shielded semiconductor detectors placed into a mounting rack ensuring measurements in either horizontal (container monitoring) or vertical (drum monitoring) counting geometry. For evaluation of measured HPGe spectra the Canberra – Packard ISOCS detection efficiency calculation code was used. A loader is used to change the measured side of the 600 L container. For metrological certification of this monitor a special prototype test container with 24 rod sources inside a regular grid was necessary to design and to use. The mentioned above vertical counting geometry together with an additional drum rotator ensures standard free release monitoring of materials in 200 l rotating drums. Successful metrological qualification of the both counting geometries at SMU Bratislava showed 20% accuracy class. A pair of NaI(Tl) detectors and a measurement and navigation frame ensuring loader shovel fixation in counting position are used for the fast sorting monitoring. The navigation of loader and its shovel to the counting geometry should be as fast as possible. The monitored results shall be indicated by a prompt light indication system (apart from storing on HDD). MCNP 5 calculation code was used for assessment of gross gamma 137Cs detection efficiency. The estimated MDA for a pair of 2″ × 2″ Na(Tl) detectors and 30 s acquisition time is about 90 Bq/kg. However, due to the counting geometry deviations from calculated values the uncertainty of measurements can be relatively high. Hence, the system is applicable for sorting monitoring only.

scholarly journals Neutrinoless Double Beta Decay with Germanium Detectors: 1026 yr and Beyond

Universe ◽  
2021 ◽  
Vol 7 (9) ◽  
pp. 341
Author(s):  
Valerio D’Andrea ◽  
Natalia Di Marco ◽  
Matthias Bernhard Junker ◽  
Matthias Laubenstein ◽  
Carla Macolino ◽  
...  
Keyword(s):  
Energy Resolution ◽  
Half Life ◽  
Detection Efficiency ◽  
Background Level ◽  
Double Beta Decay ◽  
Semiconductor Detectors ◽  
Germanium Detectors ◽  
Highly Sensitive ◽  
High Detection Efficiency ◽  
Excellent Energy Resolution

In the global landscape of neutrinoless double beta (0νββ) decay search, the use of semiconductor germanium detectors provides many advantages. The excellent energy resolution, the negligible intrinsic radioactive contamination, the possibility of enriching the crystals up to 88% in the 76Ge isotope as well as the high detection efficiency, are all key ingredients for highly sensitive 0νββ decay search. The Majorana and Gerda experiments successfully implemented the use of germanium (Ge) semiconductor detectors, reaching an energy resolution of 2.53 ± 0.08 keV at the Qββ and an unprecedented low background level of 5.2×10−4 cts/(keV·kg·yr), respectively. In this paper, we will review the path of 0νββ decay search with Ge detectors from the original idea of E. Fiorini et al. in 1967, to the final recent results of the Gerda experiment setting a limit on the half-life of 76Ge 0νββ decay at T1/2>1.8×1026 yr (90% C.L.). We will then present the LEGEND project designed to reach a sensitivity to the half-life up to 1028 yr and beyond, opening the way to the exploration of the normal ordering region.

Uncertainty Analysis of Activity Measurement of New Monitoring System for Free-Release for NPP A-1 Decommissioning, Slovakia

2011 ◽  
Author(s):  
Alojz Slaninka ◽  
Ondrej Sla´vik ◽  
Vladimi´r Necˇas
Keyword(s):  
Uncertainty Analysis ◽  
Monitoring System ◽  
Detection Efficiency ◽  
Activity Measurement ◽  
Counting Geometry ◽  
Rectangular Container ◽  
Energy Peak ◽  
Hpge Detectors ◽  
Detector Characterization

New free release monitoring post with a large volume 600 L container counting geometry was designed and developed. The monitoring system is able to monitor a material also in standard counting geometry of 200 L drum. Using counting geometry of 600 L rectangular container that is equipped with self-discharger is able to increase the total monitoring capacity. The monitoring system is based on a pair of electrically cooled semiconductor HPGe detectors that are placed into a modifiable vertical or horizontal pair of lead collimators. The monitoring system is integrated with an industrial scale for determination of massic activities of measured materials and in addition by a rotating table in the case of 200 L drums monitoring. Monitoring system is integrated into transportable ISO container with constant environmental conditions that are ensured by air-condition unit. Full-energy peak detection efficiency (FPE) polynomial curves for various densities of measured material were in both cases determined by ISOCS calibration code based on designed counting geometry and delivered ISOCS/LabSOCS detector characterization. Uncertainty analysis of massic activity measurement by container and drum monitoring system in designed counting geometry is introduced below in more detail.

Modeling an HPGe detector response to gamma-rays using MCNP5 code

2019 ◽  
Vol 30 (11) ◽  
pp. 1950099
Author(s):  
I. V. Prozorova ◽  
R. R. Sabitova ◽  
N. Ghal-Eh ◽  
S. V. Bedenko
Keyword(s):  
Computational Model ◽  
Response Function ◽  
Hpge Detector ◽  
Gamma Ray ◽  
Detection Efficiency ◽  
Dead Layer ◽  
Acquisition Time ◽  
Detector Response ◽  
Simulated Model ◽  
Mcnp5 Code

The response function is the important information for the precise interpretation of experimental data and also for characterizing the developing nuclear instruments. Measurement of the response function normally requires a number of mono-energetic gamma-ray sources, a long acquisition time and an appropriate experimental setup. The Monte Carlo method, as an alternative to response function measurement, has widely been used and recommended. In this study, a computational model of an HPGe detector has been developed by using the MCNP5 code. To validate the simulated model, the simulations from mono-energetic sources have been compared to the corresponding measured data. Any deviation from the measurement could be attributed to the unmodeled details of the detector crystal, so they needed adjustment. Moreover, an analysis has been undertaken on the dependency of detection efficiency on the dead layer thickness of the germanium crystal. Having developed a computational model of the crystal, a set of correction factors was extracted to take into account the gamma-ray self-absorption within the source volume. The simulated model of the HPGe detector in this study can be used to calculate the detection efficiency when the samples are not of the standard geometry which require self-absorption considerations.

scholarly journals Effects of electron irradiation on spectrometric properties of Schottky barrier CdTe radiation detectors

2020 ◽  
Vol 50 ◽  
pp. 2060017
Author(s):  
Katarína Sedlačková ◽  
Bohumír Zaťko ◽  
Márius Pavlovič ◽  
Andrea Šagátová ◽  
Vladimír Nečas
Keyword(s):  
Schottky Barrier ◽  
Electron Irradiation ◽  
Gamma Ray ◽  
Detection Efficiency ◽  
Pulse Height ◽  
Radiation Detectors ◽  
Peak Position ◽  
Semiconductor Detectors ◽  
Position Detection ◽  
High Detection Efficiency

High detection efficiency and good room temperature performance of Schottky barrier CdTe semiconductor detectors make them well suited especially for X-ray and gamma-ray detectors. In this contribution, we studied the effect of electron irradiation on the spectrometric performance of the Schottky barrier CdTe detectors manufactured from the chips of size [Formula: see text] mm3 with In/Ti anode and Pt cathode electrodes (Acrorad Co., Ltd.). Electron irradiation of the detectors was performed by 5 MeV electrons at RT using a linear accelerator UELR 5-1S. Different accumulated doses from 0.5 kGy up to 1.25 kGy were applied and the consequent degradation of the spectrometric properties was evaluated by measuring the pulse-height gamma-spectra of [Formula: see text] radioisotope source. The spectra were collected at different reverse voltages from 300 V up to 500 V. The changes of selected significant parameters, like energy resolution, peak position, detection efficiency and leakage current were monitored and evaluated to quantify the radiation hardness of the studied detectors. The results showed remarkable worsening of their spectrometric parameters even at relatively low applied doses of 1.25 kGy.

Progress in parallel-detection electron energy loss spectroscopy

1988 ◽  
Vol 46 ◽  
pp. 660-661
Author(s):  
Ondrej L. Krivanek
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Dynamic Range ◽  
Detection Efficiency ◽  
Acquisition Time ◽  
Electron Spectrometer ◽  
Parallel Detection ◽  
Gain Variation ◽  
Electron Energy Loss ◽  
Spectral Intensities

Parallel-detection electron energy loss spectrometers improve the detection efficiency by several hundred times compared to the traditional serial-detection spectrometers, but they have their own set of difficulties, such as the limited dynamic range of solid state detectors, the possibility of stray reflections of the intense zero loss beam giving rise to spurious background, and channel-to-channel gain variation. Fortunately, none of these difficulties is turning out to be insoluble. Here we report on improvements of the Gatan 666 parallel detection electron spectrometer in the areas of increasing the dynamic range of the detector, and in eliminating stray reflections.The increase in the dynamic range of the detector was needed especially for low energy losses (high spectral intensities), which usually saturated the detector even at the minimum acquisition time of 12 msecs. Accordingly, we have developed an electron attenuator which uses a magnetic dipole to sweep the spectrum across the detector perpendicular to the dispersion direction (Fig. 1).

A Comparison of Detection Systems for Trace Phase Analysis

1984 ◽  
Vol 28 ◽  
pp. 361-365
Author(s):  
Stephen B. Robie ◽  
Thomas R. Scalzo
Keyword(s):  
Dead Time ◽  
Detection Efficiency ◽  
Total System ◽  
Semiconductor Detectors ◽  
X Rays ◽  
X Ray Diffraction ◽  
X Ray ◽  
Detection Systems ◽  
Sufficient Energy ◽  
Graphite Monochromator

Since the introduction of semiconductor detectors with sufficient energy resolution to resolve K-alpha X-rays from the K-beta X-rays for first row transition metals, there have been several attempts (1,2) to replace traditional detector systems (scintillation detector/graphite monochromator or proportional counter/nickel filter) in X-ray diffraction with semiconductor detectors. The goal of these experiments was to increase the total system detection efficiency by combining the K-beta discrimination and X-ray detection into a single operation. These early attempts showed that the semiconductor detector based system was more efficient, however, the problem of large dead-time losses hampered development in this area.

Improved Fabrication Technique for Microstructured Solid-State Neutron Detectors

2009 ◽  
Vol 1164 ◽  
Author(s):  
Steven L Bellinger ◽  
Walter J McNeil ◽  
Douglas Scott McGregor
Keyword(s):  
Thin Film ◽  
Electric Fields ◽  
Detection Efficiency ◽  
Pulse Height ◽  
Theoretical Models ◽  
Semiconductor Detectors ◽  
Fabrication Technique ◽  
Neutron Detectors ◽  
Efficiency Performance ◽  
Improved Performance

AbstractMicrostructured semiconductor neutron detectors have superior efficiency performance over thin-film coated planar semiconductor detectors. The microstructured detectors have patterns deeply etched into the semiconductor substrates subsequently backfilled with neutron reactive materials. The detectors operate as pn junction diodes. Two variations of the diodes have been fabricated, which either have a rectifying pn junction selectively formed around the etched microstructures or have pn junctions conformally diffused inside the microstructures. The devices with the pn junctions formed in the perforations have lower leakage currents and better signal formation than the devices with selective pn junctions around the etched patterns. Further, pulse height spectra from conformally diffused detectors have the main features predicted by theoretical models, whereas pulse height spectra from the selectively diffused detectors generally do not show these features. The improved performance of the conformal devices is attributed to stronger and more uniform electric fields in the detector active region. Also, system noise, which is directly related to leakage current, has been dramatically reduced as a result of the conformal diffusion fabrication technique. A sinusoidal patterned device with 100 μm deep perforations backfilled with 6LiF was determined to have 11.9 ± 0.078% intrinsic detection efficiency for 0.0253 eV neutrons, as calibrated with thin-film planar semiconductor devices and a 3He proportional counter.

scholarly journals X-ray colour imaging

2007 ◽  
Vol 5 (21) ◽  
pp. 477-481 ◽  
Author(s):  
R.J Cernik ◽  
K.H Khor ◽  
C Hansson
Keyword(s):  
Data Collection ◽  
Imaging System ◽  
Detection Efficiency ◽  
Three Dimensional ◽  
Silicon Detector ◽  
Semiconductor Detectors ◽  
X Ray ◽  
Aluminium Powder ◽  
Spatially Resolved ◽  
Diffraction Imaging

A prototype X-ray colour imaging system has been assembled using the principle of tomographic energy-dispersive diffraction imaging (TEDDI). The new system has been tested using samples of nylon-6, aluminium powder and deer antler bone. Non-destructive three-dimensional images of the test objects have been reconstructed on a 300 μm scale with an associated diffraction pattern at each voxel. In addition, the lattice parameters of the polycrystalline material present in the sampled voxels have been determined using full pattern refinement methods. The use of multiple diffracted parallel colour X-ray beams has allowed simultaneous spatially resolved data collection across a plane of the sample. This has simplified the sample scan motion and has improved data collection times by a factor scaling with the number of detector pixels. The TEDDI method is currently limited to thin samples (approx. 1–2 mm) with light atoms owing to the very low detection efficiency of the silicon detector at X-ray energies above 25 keV. We describe how these difficulties can be removed by using semiconductor detectors made from heavier atomic material.

scholarly journals Study on temperature coefficient of CdTe detector used for x-rays detection

2017 ◽  
Vol 32 (3) ◽  
pp. 256-260
Author(s):  
Siming Guo ◽  
Jinjie Wu ◽  
Haiyan Du ◽  
Jian Zhang ◽  
Xufang Li ◽  
...  
Keyword(s):  
Temperature Coefficient ◽  
Detection Efficiency ◽  
Working Environment ◽  
Temperature Control System ◽  
Semiconductor Detectors ◽  
X Rays ◽  
Absolute Accuracy ◽  
Key Factors ◽  
Cdte Detector ◽  
Standard Detector

The temperature of the working environment is one of the key factors in determining the properties of semiconductor detectors, and it affects the absolute accuracy and stability of the standard detector. In order to determine the temperature coefficient of CdTe detector used for X-rays detection, a precise temperature control system was designed. In this experiment, detectors and radiographic source were set inside a thermostat with temperature of 0~40?C, so that the temperature can be regulated for the test of the temperature coefficient of CdTe detector. Studies had shown that, with the increase of the temperature, the energy resolution and detection efficiency of the CdTe detector would deteriorate, and under 10?C the detectors have better performance with the 8 keV X-rays.

High energy resolution spectrometer for the dedicated STEM

1984 ◽  
Vol 42 ◽  
pp. 558-559 ◽  
Author(s):  
P.E. Batson
Keyword(s):  
Collection Efficiency ◽  
Core Loss ◽  
Beam Current ◽  
High Energy ◽  
High Energy Resolution ◽  
Acquisition Time ◽  
Good Definition ◽  
Loss Analysis ◽  
Definition Of ◽  
Acceleration Voltage

Use of the STEM to obtain precise electronic information has been hampered by the lack of energy loss analysis capable of a resolution and accuracy comparable to the 0.3eV energy width of the Field Emission Source. Recent work by Park, et. al. and earlier by Crewe, et. al. have promised magnetic sector devices that are capable of about 0.75eV resolution at collection angles (about 15mR) which are great enough to allow efficient use of the STEM probe current. These devices are also capable of 0.3eV resolution at smaller collection angles (4-5mR). The problem that arises, however, lies in the fact that, even with the collection efficiency approaching 1.0, several minutes of collection time are necessary for a good definition of a typical core loss or electronic transition. This is a result of the relatively small total beam current (1-10nA) that is available in the dedicated STEM. During this acquisition time, the STEM acceleration voltage may fluctuate by as much as 0.5-1.0V.

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