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WOS: 000433206800010 The issue of pulse pile-up is frequently encountered in nuclear experiments involving high counting rates, which will distort the pulse shapes and the energy spectra. A digital method of off-line processing of pile-up pulses is presented. The pile-up pulses were firstly identified by detecting the downward-going zero-crossings in the first-order derivative of the original signal, and then the constituent pulses were reconstructed based on comparing the pile-up pulse with four models that are generated by combining pairs of neutron and.. standard pulses together with a controllable time interval. The accuracy of this method in resolving the pile-up events was investigated as a function of the time interval between two pulses constituting a pile-up event. The obtained results show that the method is capable of disentangling two pulses with a time interval among them down to 20 ns, as well as classifying them as neutrons or gamma rays. Furthermore, the error of reconstructing pile-up pulses could be kept below 6% when successive peaks were separated by more than 50 ns. By applying the method in a high counting rate of pile-up events measurement of the NEutron Detector Array (NEDA), it was empirically found that this method can reconstruct the pile-up pulses and perform neutron-gamma discrimination quite accurately. It can also significantly correct the distorted pulse height spectrum due to pile-up events. Swedish Research Council; UK STFC [ST/L005727/1]; Generalitat Valenciana, Spain [PROMETEO/2010/101]; MINECO, Spain [AIC-D-2011-0746, FPA2011-29854, FPA2012-33650]; TUBITAK, Turkey [114F473] This work was partly funded by the Swedish Research Council, by the UK STFC, under grant ST/L005727/1, by the Generalitat Valenciana, Spain, under grant PROMETEO/2010/101, by MINECO, Spain, under grants AIC-D-2011-0746, FPA2011-29854 and FPA2012-33650, and by TUBITAK, Turkey, under grant 114F473.

Hamamatsu recently announced the launch of a new type of a photodetector, a micro photomultiplier (microPMT or μPMT). This detector works like a classic photomultiplier but the whole device is made directly in a silicon wafer sandwiched between two glass layers. A microPMT has dimensions of only 13×10×2mm and its photocathode has size of 3×1mm. According to the producers, this newly developed photodetector keeps all the advantages of a classic photomultiplier such as high gain, high sensitivity, low noise, high speed, and low temperature dependence. The aim of the work is to verify usefulness of a microPMT in gamma spectrometry with scintillators and fast timing. In the first part of the study analysis of the energy resolution obtained with 3×3×1mm LSO, BGO and CsI(Tl) scintillators is made. The light pulse shapes of a single photoelectron and scintillation signal of LSO are also showed. The important part of the study are measurements of the number of photoelectrons and estimation of the excess noise factor. In the second part, measurements of the time jitter and timing resolution with LSO crystal for 511keV annihilation quanta are reported. All the results are compared with data obtained with classic PMTs.

The work is dedicated to study of optical and scintillation properties of CsI:In crystals. Using the Bridgeman method a concentration row of CsI:In single crystals was grown with the dopant content from 10⁻⁴ to 10⁻¹ mol. %. The segregation coefficient of In in CsI was estimated to be ~0.15. In CsI:In luminescence spectra one symmetric band is observed, peaking around 545 nm, with FWHM of 0.46 eV. Under intracenter excitation 1.9 μ s exponential decay was observed. The light yield under gamma excitation of ¹³⁷Cs isotope (662 keV), measured with a shaping time of 10 μ s, was 27 000 photons/MeV. The radio-luminescence yield of CsI:In , measured by the current mode method, approached to that of CsI:Tl . Probably, this difference is connected with the presence of a stronger afterglow in CsI:In crystals.

The absorption, luminescence, and scintillation characteristics of cerium-doped lutetium-yttrium perovskite (LuxY1−x AlO3:Ce; x = 0, 0.3, 0.7) single crystals were investigated. The values of light yield, scintillation decay time, and coincidence time resolution were evaluated. At 662 keV γ-rays (137Cs source), the light yield of 30 700 ph MeV−1 obtained for YAlO3:Ce is much higher than that of 16 200 and 10 600 ph MeV−1 obtained for Lu0.3Y0.7AlO3:Ce and Lu0.7Y0.3AlO3:Ce, respectively. Scintillation decays are dominated by a fast component with decay time value of 16–20 ns, which nearly coincides with the photoluminescence decay time value of 17.5 ns. In scintillation decays the intensity of the fast component becomes reduced and the content of slower components considerably increased with increasing lutetium content in the crystals. The coincidence time spectra for 511 keV annihilation quanta were measured in coincidence experiment using a BaF2-based detector and time resolution was also discussed in terms of a number of photoelectrons and decay time of the scintillation pulse. The photofraction for all the crystals under 662 keV γ-ray excitation was also evaluated and discussed.

In a spectroscopic gamma-ray scintillation detector, hot and thermalized transport, trapping, and recombination in multiple kinetic orders set the performance characteristics on which security, physics, and medical applications depend. CsI:Tl is the classic scintillator, yet even in it the details of these processes are still not fully understood. In this study, computational modeling reveals the origins of both recent and old observations about the spatial and temporal characteristics of the carrier interactions. This insight allows for improved material engineering of spectroscopic radiation detectors.

The synthesis and membrane activity of a suite of linear oligoesters containing a common diphenylacetylene unit core and differing in the hydroxyl terminus are reported. Active compounds formed high-conductance channels efficiently in both vesicle and planar bilayers, with one compound showing a very unusual slow loss of transport activity over a 20-30 min period. Steady-state and time-resolved fluorescence studies establish the rapid partition of active compounds to the bilayer and identify at least three types of membrane-associated species by their differing fluorescence lifetimes. The change in the distribution of species is correlated with the slow loss of activity. The results are interpreted in terms of an aggregate within a single bilayer leaflet that is nonetheless competent to transport ionic species through the bilayer. The properties of such structures, revealed by these compounds, appear to be consistent with commonly observed behaviors of other synthetic ion channels.

The synthesis and characterisation of the transport activity and membrane localisation of three 3-hydroxyglutarate diesters containing saturated and diphenylacetylene-derived groups are described. In bilayer vesicles and planar bilayers, the two compounds bearing a terminal carboxylic acid form active ion channels; a related neutral compound is inactive. Nonlinear current–voltage behaviour is observed for the active diphenylacetylene-derived diester. The transport activity occurs at concentrations that are substantially below the level at which the compounds aggregate. Diphenylacetylene-derived fluorescence allows the partitioning and the aggregation states of the compounds to be probed. It is clear that the active compounds do not simply act as detergents, but form defined, if irregular, ion channels in the membrane.

The performance of Lu3Al5O12:Ce (LuAG:Ce) and Y3Al5O12:Ce (YAG:Ce) scintillators were compared under γ-ray excitation using photomultiplier tube (PMT) readout. Light yield non-proportionality and energy resolution were measured with a Photonis XP5500B PMT. The energy resolution, obtained in this work for 662 keV γ-rays, was 6.7 and 7.0%, respectively, for LuAG:Ce and YAG:Ce detectors. A fast component in the scintillation decay of LuAG:Ce crystal is faster than that of YAG:Ce crystal, whereas the relative intensity of a fast component for YAG:Ce crystal is higher than that of LuAG:Ce crystal. The coincidence time resolution, obtained in this work for 511 keV annihilation quanta, was 583 and 660 ps, respectively, for LuAG:Ce- and YAG:Ce-based detectors in coincidence experiment together with a BaF2 scintillation detector. Normalized coincidence time resolution was also discussed in terms of a number of photoelectrons and decay time of the light pulse.

19th Real Time Conference (RT) -- MAY 26-30, 2014 -- Nara, JAPAN WOS: 000356458000028 This paper presents the final design and results of the FADC Mezzanine for the EXOGAM (EXOtic GAMma array spectrometer) and NEDA (Neutron Detector Array) detectors. The measurements performed include those of studying the effective number of bits, the energy resolution using HP-Ge detectors, as well as timing histograms and discrimination performance. Finally, the conclusion shows how a common digitizing device has been integrated in the experimental environment of two very different detectors which combine both low-noise acquisition and fast sampling rates. Not only the integration fulfilled the expected specifications on both systems, but it also showed how a study of synergy between detectors could lead to the reduction of resources and time by applying a common strategy. Osaka Univ, Res Nucl Phys Generalitat Valenciana, Spain [PROMETEO/2010/101]; INFN, Italy; Spanish MINECO [AIC-D-2011-0746, FPA2011-29854, FPA2012-33650]; Swedish Research Council; Scientific and Technological Research Council of Turkey (TUBITAK); UK STFC; Science and Technology Facilities Council [ST/L005735/1, ST/J000124/1, ST/L005727/1] This work was supported by the Generalitat Valenciana, Spain, under grant PROMETEO/2010/101. Some authors were supported in part by INFN, Italy, and by the Spanish MINECO under grants AIC-D-2011-0746, FPA2011-29854 and FPA2012-33650. This work was also supported by the Swedish Research Council, the Scientific and Technological Research Council of Turkey (TUBITAK) and the UK STFC.

Compact, fluorescent uracil aglycones and derivatives suitable for incorporation into the oligonucleotide mimic peptide nucleic acid (PNA) have been prepared by Sonogashira/Castro-Stephens coupling to monosubstituted phenylacetylenes. Cyclic 6-(phenyl)furo[2,3-d]pyrimidin-2(3H)-ones were accessed by the Ag + -catalyzed cyclization of the 5-alkynyluracil precursors. Although this reaction was sluggish, it gave quantitative chemical yields. Electron-rich alkynes, such as p-methoxyphenylethyne, cyclize much more rapidly than electron-deficient alkynes. Adjustment of the reaction conditions permitted the synthesis of p-nitro-phenylfuranouracil in excellent yield.

The in-situ identification of the isotope causing a radiation alarm at a border crossing is essential for a quick resolution of the case. Commonly, hand-held radioisotope identification devices (RIDs) are used to address this task. Although a number of such devices are commercially available, there is still a gap between the requirements of the users and what is actually available. Two components are essential for the optimal performance of such devices: i) The quality of the raw data-the gamma spectra, and ii) isotope identification software matching the specifics of a certain gamma detector. In this paper, we investigate new spectral gamma detectors for potential use in hand-held radioisotope identification devices. The standard NaI detector is compared with new scintillation and room temperature semiconductor detectors. The following spectral gamma detectors were included into the study: NaI(Tl), LaCl3(Ce), 6LiI(Eu), CdWO4, hemispheric and coplanar CdZnTe detectors. In the paper basic spectrometric properties are measured and compared in view of their use in RIDs

19th Real Time Conference (RT) -- MAY 26-30, 2014 -- Nara, JAPAN, WOS: 000356458000029, This paper presents the design of the NEDA (Neutron Detector Array) electronics, a first attempt to involve the use of digital electronics in large neutron detector arrays. Starting from the front-end modules attached to the PMTs (PhotoMultiplier Tubes) and ending up with the data processing workstations, a comprehensive electronic system capable of dealing with the acquisition and pre-processing of the neutron array is detailed. Among the electronic modules required, we emphasize the front-end analog processing, the digitalization, digital pre-processing and communications firmware, as well as the integration of the GTS (Global Trigger and Synchronization) system, already used successfully in AGATA (Advanced Gamma Tracking Array). The NEDA array will be available for measurements in 2016., Osaka Univ, Res Nucl Phys, Generalitat Valenciana, Spain [PROMETEO/2010/101]; INFN, Italy; Spanish MINECO [AIC-D-2011-0746, FPA2011-29854, FPA2012-33650]; Swedish Research Council; Scientific and Technological Research Council of Turkey (TUBITAK); UK STFC; Science and Technology Facilities Council [ST/J000124/1, ST/L005735/1, ST/L005727/1], This work was supported by the Generalitat Valenciana, Spain, under grant PROMETEO/2010/101. Some authors were supported in part by INFN, Italy, and by the Spanish MINECO under grants AIC-D-2011-0746, FPA2011-29854, and FPA2012-33650. The Swedish Research Council, the Scientific and Technological Research Council of Turkey (TUBITAK), and the UK STFC also provided support.

When fish strength is estimated indirectly from the sounder echo amplitudes, the inverse techniques of solving the so-called “single-beam integral equation” are quite satisfactorily used. This approach needs prior knowledge of the beam pattern PDF, as it represents the kernel of the integral equation to be solved and is usually calculated under the assumption of a uniform spatial distribution of fish. However, it may be shown that in some cases this assumption is not necessarily justified. For instance, when the density of fish increases, one receives multiple echoes from the same single fish in successive transmissions, which results in observing so-called fish echo traces. Typically used fish counting methods are either simple direct echo counting statistics or fish traces statistics [1]. Increased fish concentration is not only the reason of multiple echo formation resulting in the fish traces in consecutive pings. As it is easily seen from the geometry of the phenomenon, even a relatively low-density fish aggregation forms multiple echoes and, hence, fish traces if the vessel (or fish) relative speed is low enough and the beam pattern angular width (sampling volume) is large enough. In some situations, the uniform assumption works properly only for the cases of large numbers of samples. Taking into account this phenomenon, the accuracy of the solution can be improved by including the fish traces counting statistics in calculating the beam pattern PDF. In this paper, two different models of fish traces statistics are investigated: one assuming the vessel movement with stationary fish and the other with a stationary vessel and moving fish. Both approaches are modeled numerically and verified experimentally using the data obtained from a dual-beam system. The comparison of both approaches, i.e., for single echo traces and multiple echoes, is carried out using Windowed Singular Value Decomposition (WSVD) and Expectation Maximization and Smoothing (EMS) inverse techniques of fish target strength estimation in both the absolute domain (backscattering length estimation) and the logarithmic domain (target strength estimation).

WOS: 000344994600012, A comparative study of the neutron-gamma discrimination performance of a liquid scintillator detector BC501A coupled to four different 5 in photomultiplier tubes (ET9390kb, R11833-100, XP4512 and R4144) was carried out Both the Charge Comparison method and the Integrated Rise-Time method were implemented digitally to discriminate between neutrons and gamma rays emitted by a Cf-252 source. In both methods, the neutron-gamma discrimination capabilities of the four photomultiplier tubes were quantitatively compared by evaluating their figure-of-merit values at different energy regions between 50 keVee and 1000 keVee. Additionally, the results were further verified qualitatively using time-of-flight to distinguish gamma rays and neutrons. The results consistently show that photomultiplier tubes R11833-100 and ET9390kb generally perform best regarding neutron-gamma discrimination with only slight differences in figure-of-merit values. This superiority can be explained by their relatively higher photoelectron yield, which indicates that a scintillator detector coupled to a photomultiplier tube with higher photoelectron yield tends to result in better neutron-gamma discrimination performance. The results of this work will provide reference for the choice of photomultiplier tubes for future neutron detector arrays like NEDA. (C) 2014 Elsevier B.V. All rights reserved., Swedish Research Council; UK STFC; Generalitat Valenciana, Spain [PROMETEO/2010/101]; MINECO, Spain [AIC-D-2011-0746, FPA2011-29854, FPA2012-33650]; Chinese Scholarship Council (CSC); Science and Technology Facilities Council [ST/J000124/1, ST/L005735/1], This work was partly funded by the Swedish Research Council, by the UK STFC, and by the Generalitat Valenciana, Spain, under Grant PROMETEO/2010/101, and by MINECO, Spain, under Grants AIC-D-2011-0746, FPA2011-29854 and FPA2012-33650. X. L. Luo acknowledges the support of the Chinese Scholarship Council (CSC).

19th IEEE-NPSS Real Time Conference (RT) -- MAY 26-30, 2014 -- Nara, JAPAN, WOS: 000380588000136, The present paper aims to present the final design and results of the FADC Mezzanine for EXOGAM and NEDA detectors, focusing on the resolution performance. Finally, the conclusion shows how a common digitizing device has been integrated in an experimental environment involving low-noise and fast sampling rates. Not only the integration fulfilled the expected specifications on both systems, but also, it shows how a study of synergy between detectors has led to a reduction of resources and time by applying a common strategy., Osaka Univ, Res Nucl Phys, IEEE Nucl & Plasma Sci Soc

A series of oligoesters based on a rigid triphenyl-diyne core is described. The molecules were readily synthesized from key intermediates, and retained good solubility properties. One of the compounds displayed modest ion transport activity in vesicles, was capable of forming highly conducting single channels in planar bilayers and exhibited an irregular non-linear current–voltage response. All the reported molecules had minimal aqueous fluorescence while being highly fluorescent in less-polar media including lipid vesicles; their partitioning into the membrane could be monitored by a significant blue-shift and increase in fluorescence intensity, as well as a decreased extent of quenching in vesicles over that in water. The combined data indicated that the compounds are highly aggregated in aqueous solution, which limits their membrane partitioning and ion transport activity, in agreement with mechanisms proposed for other ‘simple’ oligoester channels.

The light output and timing characteristics of a scintillation counter constructed of plastic scintillating fibers are compared to those of a counter with identical transverse cross section of 2 cm × 3 cm made of bulk scintillator. It is shown that the timing resolution at long distances is better for the fiber than for the bulk scintillator. The improvement is a factor of 1.8 at a distance of 2 m from the phototube.

A new Tagged Neutron Inspection System (TNIS) able to detect illicit materials such as explosives and narcotics in cargo containers has been developed within the EURopean Illicit TRAfficing Countermeasures Kit (EURITRACK) project. After the R&D phase, the inspection portal has been installed and commissioned at the Rijeka seaport in Croatia, where it has been operated in connection with the existing X‐ray scanner for a first two‐month demonstration campaign. Results obtained are presented and discussed in this paper.

Fluorescent reporter groups are widely used in many areas of macromolecular science. In nucleic acid chemistry, fluorescently labeled oligonucleotides find use in the study of nucleic acid conformations, as reporters of the state of hybridization and as probes of nucleic acid-protein interactions, as well as, probes and primers for the detection and quantification of desired sequences. Often, the fluorophore is a separate and independent entity covalently attached to an otherwise unmodified oligonucleotide. Another class of fluorophore is the nucleobase analog - a chemically modified nucleobase that is unable to base pair properly. Recently, we have become interested in pyrrolocytosine ( pC ) as an intrinsically fluorescent, pairing-competent nucleobase. It has previously been shown that incorporation of pyrrolocytidine into oligonucleotides gives a fluorescent molecule that responds to the state of hybridization. We have refined the syntheses of pyrrolocytosine derivatives and the related modified uracil derivatives, furanouracil ( fU ), from cytosine and uracil respectively via three sequential steps: iodination of the nucleobase; Pd-catalyzed cross-coupling with a terminal alkyne; and metal-catalyzed cyclization. The fluorescence properties of the 5-alkynyl nucleobases and the bicyclic pC and fU analogs have been characterized and depend on: 1) the nature of the substituent on the alkyne, 2) whether the nucleobase is 5-alkynyl or cyclized, and 3) the presence of a substituent on the N 1 -position of the nucleobase. The chemistry and properties of peptide nucleic acid oligomers incorporating these types of base modifications and their possible use in point-mutation detection is presented.

Europium activated 6LiI crystal (enriched to 96% 6Li) has been studied in neutron and gamma-ray spectrometry. Two crystals of Oslash50 mm times 5 mm and Oslash30 mm times 3 mm size coupled to a calibrated Photonis XP5200 photomultiplier were tested. A response of 6LiI(Eu) to neutrons emitted from a paraffin moderated Pu-Be source has been investigated and the thermal neutron peak has been found to be located at gamma equivalent energy (GEE) of about 3.5 MeV. High sensitivity of the 6LiI(Eu) crystal is demonstrated as the neutron peak is observed at the rate as low as 10-2 counts per second. Apart from neutron spectra a light output, energy resolution and non-proportionality of the 6LiI(Eu) response versus gamma-ray energy have been measured for the two crystals. The light yield of 1.5times104 ph/MeV (about 40% of NaI(Tl)) was obtained and the energy resolution at 662 keV (Cs-137) of 7.5plusmn0.1% was found for the large crystal. The non-proportionality has been measured to have more proportional character as compared to NaI(Tl). Due to the high sensitivity to thermal neutrons and good proportionality against gamma-ray energy, the 6LiI(Eu) crystal was brought under testing with few samples of fissile nuclear materials. Shielded fissile samples can be recognized via detection of neutrons followed spontaneous fission.

Four new linear oligoesters containing a diphenylacetylene unit were prepared by fragment coupling sequences and the ion channel forming ability of the compounds was investigated. Activity in vesicles was very strongly controlled by overall length; the longest compound was effectively inactive. Planar bilayer studies established that all compounds are able to form channels, but that regular step changes in conductance depend on the location of the diphenylacetylene unit within the oligoester and on the electrolyte. The intrinsic fluorescence of the diphenylacetylene unit was used to probe aggregation and membrane localization. Both monomer (320 nm) and excimer (380 nm) emissions are quenched by copper ions; quenching of the excimer emission from an aqueous aggregate is very efficient. Time-dependent changes in the intensities of monomer and excimer emission show slow transfer of diphenylacetylene units from an aqueous aggregate to a membrane-bound monomer with subsequent growth of emission from a membrane-bound excimer. The latter species is not quenched by aqueous copper ions. The implications of these species and processes for the mechanism of ion channel formation by simple oligoesters are discussed.

Lifetimes were measured for the ${2}_{1}^{+}$, ${4}_{1}^{+}$, ${0}_{2}^{+}$, ${1}_{1}^{\mathrm{\ensuremath{-}}}$, and ${3}_{1}^{\mathrm{\ensuremath{-}}}$ levels in $^{142,144,146}\mathrm{Ba}$ using a recently developed \ensuremath{\beta}-\ensuremath{\gamma}-\ensuremath{\gamma} fast timing method. In $^{146}\mathrm{Ba}$, the ${\mathit{Q}}_{0}$ moment for the negative parity band was slightly larger than that for the positive parity band. The isovector E1 rates which were very small in $^{146}\mathrm{Ba}$ and large in $^{144}\mathrm{Ba}$ can be explained in terms of shell effects on the electric dipole moment. The new data are interpreted by both the spdf interacting boson and the reflection-asymmetric deformed shell models and provide compelling evidence for a static octupole deformation near $^{146}\mathrm{Ba}$.

The search for and study of high spin isomers produced by 12C, 14N and 16O induced reactions on targets close to N = 82 has been performed. The observed isomers were identified unambiguously by a detailed study of the excitation functions, delayed gamma-ray multiplicity and multiparametric gamma-gamma coincidences. The isomers with the highest spin above the ground state were observed in 152Er and 151Ho nuclei.

A new method of fast-timing measurements using \ensuremath{\beta}-\ensuremath{\gamma}-\ensuremath{\gamma} coincidences with ${\mathrm{BaF}}_{2}$ and plastic detectors has been used to measure a number of lifetimes for low-lying states in $^{116}$,118,120Cd in the range of 10--100 ps. The results are discussed in terms of the vibrational and intruder structure of these nuclei.

The half-lives of the excited states in 125 I and 127 I have been measured with a time-to-amplitude converter. The reduced transition probabilities B (M1) and B (E2) have been established, and the results have been compared with the predictions of the single-particle model as well as with the “pairing-plus-quadrupole-force” model used by Kisslinger and Sorensen for spherical nuclei.

The half life of the 55 keV level in Ir188 was determined with a time-to-pulse height converter to be 2.3±0.2 ns. The half-lives of levels, de-excited by the 188 and 195 keV transitions are shorter than 0.5 ns. A possible configuration of the ground and 55 keV level in Ir188 is discussed.

The half-life of the 321 keV 9 2 − level in 125 Te was determined with a time-to-amplitude converter to be 0.695±0.015 ns. The half-life limits of some higher-lying states were established. The effect of the three-quasiparticle nature of the 321 keV level on the probability of the 176 keV γ-transition de-exciting this level is discussed.

Positron computed tomography (P.C.T) is a very promising tool for research and clinical applications in nuclear medicine. P.C.T. consists in yielding images representing the distribution of positron emitting radionuclides (11C, 13N, 15O, 18F...). The selected labeled molecule is administered to the patient and the P.C.T. allows to obtain its distribution in several transverse tomographic sections as a function of time. Many molecules have been labeled with these radionuclides to investigate very important physiological and biochemical processes.

Low-lying levels in the N = 60 isotones 98Sr and 100Zr have been described in terms of the coexistence of spherical and deformed shapes. A band-mixing calculation using recently determined preliminary values for important excited state lifetimes has been carried out. The results and a discussion of the mixing are presented. Also recent experimental results concerning the level structure of the N = 62 isotone 102Zr are given.

We report here on the first study of the level structure of151Ho. High spin levels in151Ho have been populated in the141Pr+16O and144Sm+12C reactions. The level structure has been established up to 6.6 MeV energy and the spins and parities determined up to 49/2−. Most of the proposed level configurations can be explained by the coupling ofh11/2 protons tof7/2 and/orh9/2 neutrons. An isomer with 14±3 ns half-life and a delayed gamma multiplicity equal to 17±2 has been found. Its spin is larger than 57/2ħ units.