A method for measuring the volume distribution of hydrogen in various objects by means of tagged neutron probing is proposed. The existing probing methods, which permit measuring the distribution of ...some elements, are inapplicable to hydrogen since they rely on the detection of a reaction that involves gamma-ray emission and which nearly does not occur in the case of hydrogen at tagged-neutron energies. Meanwhile, hydrogen is of great interest: it enters into the composition of many substances, including organic compounds—in particular, explosives. The proposed method involves detecting neutron scattering off an object and measuring the detection time. A method for separating the case of scattering off hydrogen from the set of detected neutrons and for determining the coordinate of the scattering point is described. A numerical simulation is performed, and it is shown that the method in question provides a high spatial resolution and a fast accumulation of events of scattering off hydrogen. The method can be combined with existing methods for measuring the distributions of other elements, whereby an extension of the range of identifiable substances and a significant reduction of the consumption of the neutron-source resource could be reached.
A new method of employing
A
(
n
,
n
′γ)
A
reactions of inelastic tagged-neutron scattering is proposed for revealing hidden substances. In contrast to the well-known method where substances are ...identified by measuring the spectrum of gamma rays, the new method consists in identifying substances by measuring the spectrum of neutrons. The neutron energy is measured by the time-of-flight method via detecting a (γ,
n
) pair and invoking the parameters of tagged neutrons. The detection of a neutron in a pair with a photon is also a factor that reduces the rate of accumulation of useful events. As is shown in the present study, however, the method in question possesses a number of important special features owing to which it boasts high precision and efficiency, as well as the ability of revealing a broad range of elements and hidden substances of small volume. A numerical simulation of both methods is performed. It is shown that the required time of measurements within the proposed method is one order of magnitude shorter, which makes it possible to circumvent that main difficulty encountered in applying the known method and associated with a low resource and a high cost of neutron sources.
Neutrinoless double- Formula omitted decay of Formula omittedGe is searched for with germanium detectors where source and detector of the decay are identical. For the success of future experiments it ...is important to increase the mass of the detectors. We report here on the characterization and testing of five prototype detectors manufactured in inverted coaxial (IC) geometry from material enriched to 88% in Formula omittedGe. IC detectors combine the large mass of the traditional semi-coaxial Ge detectors with the superior resolution and pulse shape discrimination power of point contact detectors which exhibited so far much lower mass. Their performance has been found to be satisfactory both when operated in vacuum cryostat and bare in liquid argon within the Gerda setup. The measured resolutions at the Q-value for double- Formula omitted decay of Formula omittedGe ( Formula omitted = 2039 keV) are about 2.1 keV full width at half maximum in vacuum cryostat. After 18 months of operation within the ultra-low background environment of the GERmanium Detector Array (Gerda) experiment and an accumulated exposure of 8.5 kg Formula omittedyear, the background index after analysis cuts is measured to be Formula omitted around Formula omitted. This work confirms the feasibility of IC detectors for the next-generation experiment Legend.
Upgrade for Phase II of the Gerda experiment Agostini, M.; Bakalyarov, A. M.; Balata, M. ...
The European physical journal. C, Particles and fields,
05/2018, Letnik:
78, Številka:
5
Journal Article
Recenzirano
Odprti dostop
The
Gerda
collaboration is performing a sensitive search for neutrinoless double beta decay of
76
Ge
at the INFN Laboratori Nazionali del Gran Sasso, Italy. The upgrade of the
Gerda
experiment from ...Phase I to Phase II has been concluded in December 2015. The first Phase II data release shows that the goal to suppress the background by one order of magnitude compared to Phase I has been achieved.
Gerda
is thus the first experiment that will remain “background-free” up to its design exposure (
100 kg
year
). It will reach thereby a half-life sensitivity of more than
10
26
year within 3 years of data collection. This paper describes in detail the modifications and improvements of the experimental setup for Phase II and discusses the performance of individual detector components.
While preparing for an experiment on the search for neutrinoless double β decay of
150
Nd nuclei, the spectrometric properties of polystyrene were investigated, including the dependence of the ...photomultiplier pulse amplitude on the energy of detected electrons. It is shown that a good description of experimental data is attained by taking the energy loss in passive materials, changes in the ionization density at low energies, and additional light due to Cherenkov radiation generated in polystyrene into account.
A compact low-background setup for measuring radioactive contaminants in various materials is described. Two combined scintillation detectors consisting of two crystals with various decay times are ...used in the setup. In its sensitivity, the setup ranks between portable radiation-monitoring devices, whose sensitivity is insufficient for some applications, and unique large high-sensitivity systems. It may be a prototype of setups for radiation monitoring of samples for a wide range of applications.
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