The effect of temperature changes on the light output of LAB based liquid scintillator is investigated in a range from
-
5
to
30
∘
C with
α
-particles and electrons in a small scale setup. Two PMTs ...observe the scintillator liquid inside a cylindrically shaped aluminum cuvette that is heated or cooled and the temperature dependent PMT sensitivity is monitored and corrected. The
α
-emitting isotopes in dissolved radon gas and in natural Samarium (bound to a LAB solution) excite the liquid scintillator mixtures and changes in light output with temperature variation are observed by fitting light output spectra. Furthermore, also changes in light output by compton electrons, which are generated from external calibration
γ
-ray sources, is analysed with varying temperature. Assuming a linear behaviour, a combined negative temperature coefficient of
(
-
0.29
±
0.01
)
%
/
∘
C
is found. Considering hints for a particle type dependency, electrons show
(
-
0.17
±
0.02
)
%
/
∘
C
, whereas the temperature dependency seems stronger for
α
-particles, with
(
-
0.35
±
0.03
)
%
/
∘
C
. Due to a high sampling rate, a pulse shape analysis can be performed and shows an enhanced slow decay component at lower temperatures, pointing to reduced non-radiative triplet state de-excitations.
The photodissociation of the deuteron is a key reaction in Big Bang nucleosynthesis, but is only sparsely measured in the relevant energy range. To determine the cross section of the d(γ,n)p reaction ...we used pulsed bremsstrahlung and measured the time-of-flight of the neutrons. In this article, we describe how the efficiency of the neutron detectors was experimentally determined and how the modification of the neutron spectrum by parts of the experimental setup was simulated and corrected.
Korea has developed a Helium Cooled Ceramic Reflector Test Blanket Module (Ko HCCR TBM) related to the ITER project. Tungsten is considered as a prime candidate for the plasma facing materials in ...fusion reactors, and for the structure material of Ko HCCR TBM. KAERI (Korea Atomic Energy Research Institute) has been evaluating neutron cross sections of tungsten isotopes for neutron energy of up to 150 MeV based on nuclear reaction codes and available measurement data. New experimental data were measured at nELBE of HZDR (Helmholtz-Zentrum Dresden-Rossendorf) for a comparison with the evaluated and existing measurement data. The neutron source nELBE adopts a 40 MeV superconducting electron linac and a liquid Pb target for time-of-flight measurements. The nELBE neutron source uses no moderator and provides fast neutrons. An electron bunch length of 5 ps and a compact target provide a good neutron energy resolution with a relatively short flight length compared to other time-of-flight neutron sources. Transmission data of a natural tungsten sample were measured with a flight path length of 852.1 cm and a repetition rate of 101.56 kHz. The neutron total cross section of natural tungsten was obtained for an energy range of 100 keV to 10 MeV.
Characterization of the neutron beam at nELBE Beyer, R.; Birgersson, E.; Elekes, Z. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2013, Letnik:
723
Journal Article
Recenzirano
The neutron time-of-flight setup nELBE at the Helmholtz-Zentrum Dresden-Rossendorf uses an intense electron beam impinging on a liquid-lead target to produce neutrons in the energy range from about ...10keV to 10MeV. This neutron source will be used to measure fast-neutron induced reactions with relevance for future nuclear transmutation facilities and nuclear waste management. The spatial profile, the intensity, the energy distribution and the time structure of the nELBE neutron beam have been investigated and the techniques how they were measured are explained in this work.
The Formula omitted-particle light response of liquid scintillators based on linear alkylbenzene (LAB) has been measured with three different experimental approaches. In the first approach, Formula ...omitted-particles were produced in the scintillator via Formula omittedC(n, Formula omitted) Formula omittedBe reactions. In the second approach, the scintillator was loaded with 2 % of Formula omittedSm providing an Formula omitted-emitter, Formula omittedSm, as an internal source. In the third approach, a scintillator flask was deployed into the water-filled SNO+ detector and the radioactive contaminants Formula omittedRn, Formula omittedPo and Formula omittedPo provided the Formula omitted-particle signal. The behavior of the observed Formula omitted-particle light outputs are in agreement with each case successfully described by Birks' law. The resulting Birks parameter kB ranges from Formula omitted to Formula omitted cm/MeV. In the first approach, the Formula omitted-particle light response was measured simultaneously with the light response of recoil protons produced via neutron-proton elastic scattering. This enabled a first time a direct comparison of kB describing the proton and the Formula omitted-particle response of LAB based scintillator. The observed kB values describing the two light response functions deviate by more than Formula omitted. The presented results are valuable for all current and future detectors, using LAB based scintillator as target, since they depend on an accurate knowledge of the scintillator response to different particles.
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