Conveners
Low Level γ-ray Spectrometry
- Franz Josef Maringer (BOKU - University of Natural Resources and Life Sciences, Vienna)
This talk presents the decomposition of the background spectra of the 4 screening detectors GeMPI 1 - 4 at the Gran Sasso Underground Laboratory (LNGS) using Monte Carlo simulations in the Geant4 based framework MaGe. The GeMPI detectors are low background Ge spectrometers located at a depth of 3500 m.w.e. and achieve extremely high sensitivities in material screening at a level of µBq/kg....
The Cavezzo meteorite was recovered on January 4$^{th}$, 2020, just three days after the fall, observed over Northern Italy by the all-sky cameras of the Italian PRISMA fireball network. Two specimens, weighing 3.1 g (F1) and 52.2 g (F2), were collected in the predicted strewn-field and the meteorite was classified as an L5 anomalous chondrite.
The γ-activity of F2 sample was measured at the...
ABSTRACT
Gamma spectrometry is a widely used technique for the measurement of gamma-emitting nuclides and is used in a wide range of applications in radiation protection, nuclear security and environmental sciences. One of the critical steps in analysing the spectrum includes the decision on which nuclides are present in the sample. Many laboratories report the Minimum Detectable Activity...
The measurements of Ra-226 are often performed using gamma-ray spectrometry. These measurements are however usually not direct. In most cases, progeny radionuclides, such as Bi-214 and Pb-214 are used to calculate the Ra-226 activity. An important condition ensuring accuracy of these measurements is the secular equilibrium between Rn-222 and its progenies. This condition can be met by the use...
We describe the development and construction of the high-purity germanium detector setup
CONRAD (CONus RADiation) to characterize and monitor background radiation over a wide
energy range.
The CONUS experiment is measuring coherent scattering of reactor anti neutrinos on Ge nuclei at the nuclear power plant at Brokdorf, Germany. CONRAD has been used for background studies inside the CONUS...
Due to its optical and electrical properties, polytetrafluoroethylene (PTFE) is an indispensable construction material for many modern rare event searches. Thus, the radioactive contamination of PTFE therein needs to be as low as possible. We present a cross-sectional study investigating the radioactive contamination of PTFE samples from major European suppliers of raw PTFE. The bulk...
The standard ISO 11929-3:2019 (ISO 2019) warmly recommends the use of the (generalised) least-squares method (LSQ) in the determination of characteristic limits, calculated from gamma-ray spectra. To calculate the decision threshold, it prescribes the analysis of the spectral region, comprising the most prominent peak of the gamma-ray emitter of interest i.e. the measurand. As the decision...
Two low-background, digital gamma-ray spectrometers with digital data acquisition systems have been designed and developed in the Department of Nuclear Physical Chemistry, Institute of Nuclear Physics Polish Academy of Sciences (IFJ PAN), Krakow, Poland.
The first spectrometer is equipped with Broad Energy Germanium detector BE5030 (Canberra, USA), multi-layer passive shield and active...
The Comprehensive Nuclear Test-Ban Treaty (CTBT) International Monitoring System (IMS) provides a network of 80 Radionuclide detection systems, strategically positioned around the globe with the aim of detecting particulate radionuclide emissions from nuclear explosions. The authors have undertaken research, with the aim of increasing the overall sensitivity of the monitoring regime both...
As part of the CTBTO verification regime, the radionuclide component of the International Monitoring System (IMS) is based on 80 particulate stations and 40 noble gas systems. Daily gamma spectral data are transmitted to the International Data Centre (IDC) in Vienna for automatic processing and interactive analysis.
Data analysis aims at monitoring a list of CTBT relevant radionuclides. These...
For low-level gamma-spectrometers situated at medium deep underground laboratories the cosmic radiation still causes a significant contribution to the background count rate. The cosmic component here mainly consists of muons and neutrons produced by muonic reactions. Our investigations were performed in the underground laboratory Felsenkeller, situated at a depth of 138 m.w.e. At this level...
Galactic cosmic rays produce neutrons when they interact with the Earth’s atmosphere. In gamma-ray spectrometers these neutrons can be scattered and captured in the materials of the shield and the detector, producing signals in the spectrometer’s background. By the end of the eighties, at JSI, a new spectrometer was built, housing a germanium detector with a relative efficiency of 36% in a...
In the context of environment monitoring, we aim at (i) reducing the time between the sampling and the detection of radionuclides in the samples and (ii) computing a precise estimation of the activity in the sample we analyse, particularly at low-level. To achieve this, we focus on a full spectrum analysis algorithm on gamma-ray spectrum obtained on HPGe detectors.
Full spectrum analysis has...
ABSTRACT
COSSU has been developed at the Radiation and Nuclear Safety Authority of Finland to improve the sensitivity of the measurement in the Gamma Laboratory. COSSU is a multi-detector gamma coincidence device that is used for the analysis of routine environmental monitoring samples. In addition, it can be used in the studies of more complex cases, for example, samples that have low...
The low-level radioanalysis laboratory is performing part of its measurements of environmental samples using high-resolution gamma spectrometry. These samples are of various types: water, soils, plants, biologicals, aerosols. They are held in different containers for liquids and solids (from few milliliters to 500 milliliters), centering devices are used for aerosol filters.
The laboratory...
In this work we present the characterization of a BEGe (Broad Energy Germanium) type HPGe (High Purity Germanium) detector, with a Carbon Fiber entrance window (typically ~0.6 mm thick) and an active area of 6305 mm2, operated at shallow depth in Abu Dhabi. The shielding is made of 6 inch lead [5 inch ordinary low-background lead; and 1 inch of low 210Pb content] and a...
The GeMSE (Germanium Material and meteorite Screening Experiment) facility operates a low-background HPGe crystal in an underground laboratory in Switzerland, with a moderate rock overburden of 620 m.w.e.. It is devoted to material screening for rare event search experiments in astroparticle physics as well as characterization of meteorites. A multi-layer passive shielding, a muon veto and a...
The Astroparticle Physics Group at the University of Zurich operates the high-purity germanium (HPGe) $\gamma$-ray spectrometer Gator in a low-background environment at the Gran Sasso Underground Laboratory in Italy. It is used to screen and select materials for rare-event search experiments such as XENON, DARWIN, GERDA and LEGEND. The 2.2 kg HPGe crystal is surrounded by a passive shield made...
ABSTRACT
Free release and/or controlled reuse of lead originating from controlled areas of the SCK•CEN requires, amongst other tests, low-level radioactivity measurements of these materials. For that purpose, the lead is collected, characterized for its radioactivity content and segregated in batches with similar destination. Each batch is than melted and poured into ingots. From each batch,...
The key tasks considering low-level gamma spectrometry analysis is creating an adequately accurate detection efficiency function, taking into consideration different energies, matrices and sample-detector geometries. The detection efficiency refers to the full energy peak efficiency (FEPE), which is defined as the ratio of the number of detected radiation events in the photo-peak and the total...
