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Swiderski L.,Andrzej Soltan Institute for Nuclear Studies | Moszynski M.,Andrzej Soltan Institute for Nuclear Studies | Wolski D.,Andrzej Soltan Institute for Nuclear Studies | Iwanowska J.,Andrzej Soltan Institute for Nuclear Studies | And 7 more authors.
IEEE Transactions on Nuclear Science | Year: 2010

Performance of a He-3 counter and a B-10 loaded liquid scintillator EJ309B5 has been studied in terms of neutron detection efficiency. The measurements were carried out in a mixed field of neutron and gamma radiation from an intense (∼ 106 neutrons/s/4π252Cf source. The response of both detectors to background and high intensity gamma radiation (∼ 100 μSv/h at a detector) from a 60Co source has been measured to establish background count rate and gamma rays cut-off point, respectively. The analysis showed that the properties of a He-3 counter are significantly better than that of EJ309B5. However, it has been pointed out how to improve the performance of a liquid scintillator in order to reduce gamma radiation sensitivity. © 2010 IEEE.


Swiderski L.,Andrzej Soltan Institute for Nuclear Studies | Wolski D.,Andrzej Soltan Institute for Nuclear Studies | Batsch T.,Andrzej Soltan Institute for Nuclear Studies | Iwanowska J.,Andrzej Soltan Institute for Nuclear Studies | And 10 more authors.
IEEE Transactions on Nuclear Science | Year: 2010

Boron-10 loaded liquid scintillators were studied in order to improve n/γ separation. Pulse shape discrimination (PSD) was implemented by means of a zero-crossing (ZC) method to distinguish between γ-rays and fast/slow neutrons. Significant progress was done for BC523A2 and EJ339A2 scintillators loaded with reduced amount of 10B(2% and 2.5%, respectively), as compared to the results obtained earlier with BC523A loaded with 4.4% of 10B. The improvement was probably caused by the reduction of content, as indicated in the reported study. A 10B loaded scintillator EJ309B5 based on non-flammable liquid was also studied, showing the best separation of thermal neutron capture events from fast neutrons, γ-rays and noise. © 2010 IEEE.


Szczesniak T.,Andrzej Soltan Institute for Nuclear Studies | Moszynski M.,Andrzej Soltan Institute for Nuclear Studies | Syntfeld-Kazuch A.,Andrzej Soltan Institute for Nuclear Studies | Swiderski L.,Andrzej Soltan Institute for Nuclear Studies | And 8 more authors.
IEEE Transactions on Nuclear Science | Year: 2010

Liquid scintillators loaded with boron-10 or lithium-6 are capable to detect gamma rays, fast neutrons and also thermal neutrons. One of the popular methods applied in order to distinguish events originating from different particles is the pulse shape discrimination (PSD). The previously presented study of boron-10 loaded liquid scintillators using the PSD method showed different discrimination performance in scintillators such as BC523A, BC523A2, EJ339A2 and EJ309B5. It triggered a further study of the light pulse shapes in these scintillators originating from events related to gamma rays, fast and thermal neutrons. The light pulse shapes, measured using the single photon method, were recorded together with the 2-dimensional n/gamma discrimination data. Next, the recorded light pulses were gated using energy and the PSD information to extract pulses characteristic of the only one kind of particles. Finally, the analysis of the light pulse shapes with multi-exponential fits and calculation of decay time constants and intensities of components were performed. The results were compared with the data obtained for liquid scintillators not sensitive to thermal neutrons BC501A, EJ301 and EJ309. © 2010 IEEE.


Swiderski L.,Andrzej Soltan Institute for Nuclear Studies | Moszynski M.,Andrzej Soltan Institute for Nuclear Studies | Wolski D.,Andrzej Soltan Institute for Nuclear Studies | Iwanowska J.,Andrzej Soltan Institute for Nuclear Studies | And 3 more authors.
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | Year: 2011

Methods to reduce gamma-ray sensitivity of a liquid scintillator EJ309 have been studied. Zero-crossing pulse shape discrimination method was used to separate events generated by neutron and gamma radiation between 60- keVee and 4 MeVee. The measurements were carried out under irradiation from an intense 137Cs source, yielding dose rate of 10 mR/h at the detector. A PuBe source was used to establish neutron integration window. Pile-up rejection (PUR) circuit was used to reduce gamma-ray induced events under irradiation from an intense gamma-ray source. Further, application of lead, tin and copper shields was done in order to decrease intrinsic gamma-neutron detection efficiency. © 2011 Elsevier B.V.


Cherepy N.J.,Lawrence Livermore National Laboratory | Sanner R.D.,Lawrence Livermore National Laboratory | Beck P.R.,Lawrence Livermore National Laboratory | Swanberg E.L.,Lawrence Livermore National Laboratory | And 3 more authors.
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | Year: 2015

Transparent plastic scintillators based on polyvinyltoluene (PVT) have been fabricated with high loading of bismuth carboxylates for gamma spectroscopy, and with lithium carboxylates for neutron detection. When activated with a combination of standard fluors, 2,5-diphenyloxazole (PPO) and tetraphenylbutadiene (TPB), gamma light yields with 15 wt% bismuth tripivalate of 5000 Ph/MeV are measured. A PVT plastic formulation including 30 wt% lithium pivalate and 30 wt% PPO offers both pulse shape discrimination, and a neutron capture peak at ~400 keVee. In another configuration, a bismuth-loaded PVT plastic is coated with ZnS(6Li) paint, permitting simultaneous gamma and neutron detection via pulse shape discrimination with a figure-of-merit of 3.8, while offering gamma spectroscopy with energy resolution of R(662 keV)=15%. © 2015 Elsevier B.V. All rights reserved.

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