Development and performance of a low-background
γ-ray spectrometer are described. The spectrometer consists of a 131% efficient Ge detector in U-type configuration. The passive shielding consists of ...ultrapure lead of 6″ thickness. A top muon guard is used as an active shielding. The spectrometer and shielding are positioned inside a steel room made of 6″-thick pre-World War II iron. The steel room is located underground with
33
m
of water-equivalent overburden. The total integrated background rate in the energy range 50–
2700
keV
was measured at
0.068
counts
per
second
per
100
cm
3
Ge volume. The spectrometer serves as a reference instrument for low-level and highly accurate environmental radioactivity measurements. One specific application of
228
Ra
determination in drinking water is described. With a
1
l
water sample, 1-step chemical procedure, and
1000
min
counting time, a detection limit
L
d=20
mBq/l
(0.55
pCi/l)
was reached, which meets the EPA mandated limit of
1
pCi/l
. Methods of upgrading the spectrometer as well as the predicted improvements in
228
Ra
detection, including direct counting of water without chemical processing, are discussed.
Performance of a Small Anode Germanium Well detector Adekola, A.S.; Colaresi, J.; Douwen, J. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
06/2015, Letnik:
784
Journal Article
Recenzirano
The performance of Small Anode Germanium (SAGe) Well detector 1 has been evaluated for a range of sample sizes and geometries counted inside the well, on the end cap or in Marinelli beakers. The SAGe ...Well is a new type of low capacitance germanium well detector manufactured using small anode technology. The detector has similar energy resolution performance to semi-planar detectors, and offers significant improvement over the Coaxial and existing Well detectors. Resolution performance of 0.75keV Full Width at Half Maxiumum (FWHM) at 122keV γ-ray energy and resolution of 2.0–2.3keV FWHM at 1332keV γ-ray energy are guaranteed. Such outstanding resolution performance will benefit environmental applications in revealing the detailed radionuclide content of samples, particularly at low energy, and will enhance the detection sensitivity resulting in reduced counting time. This paper reports the counting performance of SAGe Well detector for range of sample sizes and geometries and how it compares to other detector types.
Characterisation of a small electrode HPGe detector Unsworth, C.; Boston, A.J.; Boston, H.C. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2019, Letnik:
927
Journal Article
Recenzirano
Odprti dostop
Small electrode HPGe detectors in an inverted coaxial geometry are increasingly in use in applications where both high efficiency and excellent energy resolution are required. The unusual electric ...field configuration of these detectors results in extremely long charge collection times compared to planar and coaxial devices. In this work we have characterised such a detector using gamma-ray coincidence measurements and optimised an electric field simulation to reproduce the positional variation of detector response. We show that, alongside accurate crystal geometry and applied electric potential, a temperature correction is crucial to correctly determining appropriate charge carrier mobility parameters. This work will help to guide the future development of HPGE detectors for applications including radioactive waste assay, radio-isotope dating, and fundamental nuclear physics.
Environmental scientific research requires a detector that has sensitivity low enough to reveal the presence of any contaminant in the sample at a reasonable counting time. CANBERRA developed the ...germanium detector geometry called Small Anode Germanium (SAGe) Well detector, which is now available commercially. The SAGe Well detector is a new type of low capacitance germanium well detector manufactured using small anode technology capable of advancing many environmental scientific research applications. The performance of this detector has been evaluated for a range of sample sizes and geometries counted inside the well, and on the end cap of the detector. The detector has energy resolution performance similar to semi-planar detectors, and offers significant improvement over the existing coaxial and Well detectors. Energy resolution performance of 750 eV Full Width at Half Maximum (FWHM) at 122 keV γ-ray energy and resolution of 2.0-2.3 keV FWHM at 1332 keV γ-ray energy are guaranteed for detector volumes up to 425 cm3. The SAGe Well detector offers an optional 28 mm well diameter with the same energy resolution as the standard 16 mm well. Such outstanding resolution performance will benefit environmental applications in revealing the detailed radionuclide content of samples, particularly at low energy, and will enhance the detection sensitivity resulting in reduced counting time. The detector is compatible with electric coolers without any sacrifice in performance and supports the CANBERRA Mathematical efficiency calibration method (In situ Object Calibration Software or ISOCS, and Laboratory SOurceless Calibration Software or LABSOCS). In addition, the SAGe Well detector supports true coincidence summing available in the ISOCS/LABSOCS framework. The improved resolution performance greatly enhances detection sensitivity of this new detector for a range of sample sizes and geometries counted inside the well. This results in lower minimum detectable concentrations compared to Traditional Well detectors. The SAGe Well detectors are compatible with Marinelli beakers and compete very well with semi-planar and coaxial detectors for large samples in many applications.
The 96.4 day exposure of a 3 kg ultra-low noise germanium detector to the high flux of antineutrinos from a power nuclear reactor is described. A very strong preference (\(p<1.2\times10^{-3}\)) for ...the presence of a coherent elastic neutrino-nucleus scattering (CE\(\nu\)NS) component in the data is found, when compared to a background-only model. No such effect is visible in 25 days of operation during reactor outages. The best-fit CE\(\nu\)NS signal is in good agreement with expectations based on a recent characterization of germanium response to sub-keV nuclear recoils. Deviations of order 60\% from the Standard Model CE\(\nu\)NS prediction can be excluded using present data. Standing uncertainties in models of germanium quenching factor, neutrino energy spectrum, and background are examined.
Phys. Rev. D 104, 072003 (2021) The deployment of a low-noise 3 kg p-type point contact germanium detector at
the Dresden-II power reactor, 8 meters from its 2.96 GW$_{th}$ core, is
described. This ...location provides an unprecedented (anti)neutrino flux of
8.1$\times 10^{13} ~\bar{\nu_{e}}/$cm$^{2}$s. When combined with the 0.2
keV$_{ee}$ detector threshold achieved, a first measurement of CE$\nu$NS from a
reactor source appears to be within reach. We report on the characterization
and abatement of backgrounds during initial runs, deriving improved limits on
extensions of the Standard Model involving a light vector mediator, from
preliminary data.
The deployment of a low-noise 3 kg p-type point contact germanium detector at the Dresden-II power reactor, 8 meters from its 2.96 GW\(_{th}\) core, is described. This location provides an ...unprecedented (anti)neutrino flux of 8.1\(\times 10^{13} ~\bar{\nu_{e}}/\)cm\(^{2}\)s. When combined with the 0.2 keV\(_{ee}\) detector threshold achieved, a first measurement of CE\(\nu\)NS from a reactor source appears to be within reach. We report on the characterization and abatement of backgrounds during initial runs, deriving improved limits on extensions of the Standard Model involving a light vector mediator, from preliminary data.
PDF
