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In this work, we tested the effect of adding a volume term to the surface term in our modified optical potential in the case of elastic neutron scattering of spin-zero [sup.40]Ca nucleus in the incident energy range between 30-50 MeV. This is achieved in two steps. First, we fit our theoretical elastic angular distribution scattering using the surface term in our velocity-dependent optical potential concerning the experimental data. Then, we adjust our theoretical elastic angular distribution scattering with the experimental data after adding the volume term into our velocity-dependent optical potential. The second step is comparing the two fits and noticing the effect of adding a volume term to the surface term. Clearly, the modified optical potential using the volume term resulted in excellent fits to the experimental data, most notably the pronounced large angle, backscattering minima, which depend sensitively on the incident energies and which have long been associated with nonlocalities. We assume the nonlocality to be due to interaction between the incident neutrons and the nucleons inside the target. Key words: neutron elastic scattering, velocity-dependent optical potential, nonlocality, surface term, volume term. Nous testons ici les effets d'ajouter un terme de volume au terme de surface deja present dans notre potentiel optique modifie pour etudier la diffusion elastique de neutrons par des noyaux sans spin de [sup.40]Ca dans le domaine d'energie de 30 a 50 MeV. Le travail se fait en deux etapes. D'abord nous procedons a un ajustage numerique (fit) de notre distribution angulaire elastique theorique utilisant notre potentiel optique avec dependance sur la vitesse et le seul terme de surface et nous refaisons l'exercice d'ajustement numerique apres avoir ajoute un terme de volume. Dans la deuxieme etape, nous comparons les deux ajustements numeriques et notons l'effet de l'ajout du terme de volume. Nous constatons alors clairement que le potentiel contenant le terme de volume donne un meilleur ajustement aux valeurs experimentales, particulierement en ce qui a trait a la diffusion aux grands angles, la diffusion arriere, qui depend beaucoup de l'energie incidente et a longtemps ete associee a la non localite, que nous supposons etre due a l'interaction entre le neutron incident et les nucleons a l'interieur du noyau. [Traduit par la Redaction] Mots-cles: diffusion elastique de neutrons, potentiel optique dependant de la vitesse, non localite, terme de surface, terme de volume., 1. Introduction It has been about 60 years since it was first suggested that the interaction of nucleons with nuclei could be represented by a complex potential, and since then [...]

The optimum Teflon [([C.sub.2][F.sub.4]).sub.n] thickness for fast neutron detection through the [sup.19]F(n,[alpha])[sup.16]N reaction was calculated and found to be [approximately equal to] 5.0 cm. Here, the 6.13 MeV [gamma] ray emitted by [sup.16]N is assumed to be detected by a Ge diode. The geometry of the system is discussed and the [gamma] line intensity was found to vary weakly with Teflon thickness., 1 Introduction Several methods are used in the literature for fast neutron detection. Among those methods are: (1) the detection of protons recoiling from the impinging neutrons [1], (2) the [...]

This paper presents upset rates of flip-flops in 65 nm commercial bulk technology predicted through modeling, and compares the predictions to upset rates measured with thorium foil, 15 MeV carbon ions, and 148 MeV protons. This paper demonstrates that 15 MeV carbon ions can be used to emulate the daughter products of neutron spallation reactions. Index Terms--Flip-flop, single-event upset (SEU), soft error.

Simulation of energy deposition in silicon by nuclear reactions is a crucial point for single event prediction tool development. In order to compare with the simulation of nuclear reactions, a silicon diode is irradiated by a 30 MeV and 63 MeV neutron beam and the energy deposited by each nuclear reaction is measured. Simulation of the ionizing energy deposition in the irradiated diode is performed by the Monte Carlo method using nuclear reaction databases. Neutron beam spectra and surrounding materials are taken into account. Experimental and simulated results are shown to be in good agreement. Index Terms--Monte Carlo methods, neutron beams, neutron detectors, radiation effects.

Current technologies are sensitive to low Linear Energy Transfer particles such as alphas. These particles can be spontaneously produced by some radioactive elements, called alpha-emitters. Here, we investigate two examples of emitters, Hafnium and Uranium. By calculating the disintegration rate in a modern technology with hafnium dioxide, we show that hafnium has no incidence on Soft Error Rate. Moreover, from Monte Carlo simulations, we point out that natural Uranium concentration in a silicon wafer lead to a Soft Error Rate comparable to that due to neutrons at ground level. Index Terms--Alpha emitter, contamination, hafnium, impurities, neutrons, pollutant, radioactive materials, radioactivity, soft error rate, uranium.

Author(s): Xinlin Li (corresponding author) [1, 2]; Richard Selesnick [3]; Quintin Schiller [4]; Kun Zhang [1, 2]; Hong Zhao [1]; Daniel N. Baker [1]; Michael A. Temerin [5] The Galaxy [...]

Small-angle neutron and X-ray scattering (SAXS) are used for examining the structural evolution of a diamond-type bicontinuous lipid cubic phase upon application of thermal and chemical stimuli. The structure-based concept has described the release of encapsulated guest molecules from stimuli-responsive and self-regulated cubosomic nanocarriers.

The influence of neutron irradiation on the nonlinear elastoplastic deformation of the constructions components under cyclic force disturbance was investigated. The formula of irradiation reinforcement was suggested depending on the experimental data, and the theorem of variable loading was proved. The problem of metal-polymeric sandwich beam was solved numerically. Keywords: Cyclic loading, Neutron flow, Boundary-value problem, Sandwich beam, INTRODUCTION Radiation treatment of rigid bodies is known to produce numerous effects which result in the appearance of additional volume deformations, and changes in the elastic (especially plastic) properties of [...]

Spatially resolved small-angle neutron scattering [SANS] was used to investigate the flow-induced effects in mixed surfactant mesophases. It was found that the two different surfactant mixtures have different relative amounts of lamellar and micellar components which results in some differences in the flow-induced response.

Power operational amplifiers were irradiated in a mixed neutron and gamma radiation environment. These experiments showed that the degradation of the power operational amplifiers shares a great deal of characteristics with that of the low signal devices (e.g., shift of the input offset voltage, increase of the input bias currents, and degradation of the frequency behavior). However, other phenomena were observed without equivalence in the family (linear dependence of the inverse of the quiescent current on the neutron fluence, more significant degradation of the negative output current and collapse of the primary operational amplifiers). These phenomena were explained from the special characteristics of the output stage, optimized to provide a current of several amperes. Finally, even though power devices are especially sensitive to radiation damage, some of the tested devices are suitable for radiation levels on the order of 5 * [10.sup.13] - [10.sup.14] n * [cm.sup.-2] in case the whole electronic system, in which the device is integrated, is carefully designed. Index Terms--Bipolar technology, neutron damage, operational amplifers, power devices, radiation tolerance.

A combination of neutron diffraction with isotopic substitution, empirical potential structure refinement modeling and small angle neutron scattering at three concentrations are used to study the structure and hydration of L-proline in aqueous solution. The study results show the proline's weak interaction with other praline molecules in solution and its strong interaction with the surrounding water environment without significantly perturbing the bulk water structure.

A new type of high performance and compact neutron collimator can be manufactured from Gd- or B-doped microchannel plates (MCPs). Structures only a few mm thick have very narrow rocking curves and high out-of-angle rejection ratios, as observed previously with a cold neutron beam. We present the results of measurements with a collimated (L/D ratio ~ 280 : 1) thermal neutron beam. MCP collimators doped with 3 mole % of [sup.nat][Gd.sub.2][O.sub.3] as well as doped with 10 mole % of [sup.10][B.sub.2][O.sub.3] were calibrated for transmission versus tilt angle. The MCPs used in this study were only 0.6 and 0.8 mm thick with ~ 8.5 [micro]m circular pores on 11.5 [micro]m centers. All the measured rocking curves agree well with the theoretically predicted performance. Both experimental and modeling results indicate that very efficient MCP collimators (with < 0.1[degrees] wide rocking curves and a rejection ratio exceeding [10.sup.3]) can be built with the existing technology. The possibility to manufacture collimators with very large L/D ratios exceeding 1000:1 is also discussed for the case of unetched MCPs. The peak transmission of such devices with very sharp rocking curves will be limited to ~ 40 % by the transmission of the undoped glass. Application of MCP collimators for scatter rejection in neutron radiography is also considered in terms of possible image distortions, which are shown to occur only for the systems with detector spatial resolution better than 20 [micro]m FWHM. Index Terms--Collimators, neutron optics, neutron scattering.

Neutron diffraction was used along with density-functional theory (DFT) to structurally investigate fully deuterated liquid N- methylacetamide ([NMA.sub.d7]) at 308 Kelvin and atmospheric pressure. The results indicate that the contribution of the intramolecular interactions in liquid NMA is well accounted for by either trans or cis molecule, and the theoretical structure factors deduced from either a linear trans trimer or a ring cis trimer are in good agreement with the experimental neutron structure factor.

The transverse acoustic modes (TAMs) for the homologous series of [alpha],[omega]-diamines ([H.sub.2]N[(C[H.sub.2]).sub.n]N[H.sub.2]) (n = 2-10, n = 12) as well as for the biogenic polyamines spermidine and spermine are analyzed by Raman and inelastic neutron scattering (INS) spectroscopies combined with density functional theory (DFT) calculations. The study has allowed the achievement of a complete and reliable assignment of all the low energy modes of these systems, both transverse and longitudinal.

Neutron diffraction with isotopic substitution (NDIS) experiments and molecular dynamics (MD) simulations are used to study the structuring in aqueous solution of two cesium salts, cesium carbonate, and cesium nitrate. The results are dominated by the strength and geometry of the direct first-neighbor interactions that describe the differences in the clustering behavior between the two solutions without need to refer to longer-range water-water structuring.

The hydration- and temperature-dependent dynamic behavior of graphite oxide is investigated by quasielastic neutron scattering using the time-of-flight spectrometer NEAT. The dynamic behavior of hydrated graphite oxide is described with the help of a consistent model that combines two two-site jump motions for the motions of the water molecules and the motions of the OH groups.

[Pb.sub.1-x][Cd.sub.x]TiO3 compounds in the tetragonal phase were prepared by the solid state reaction. Neutron powder diffraction study revealed that [Pb.sub.1-x][Cd.sub.x]TiO3 exhibits an unusual structural property.

This paper reports on NIEL calculation methods. The software code NEMO (Niel Evaluation Model of ONERA) has been used in this study. This toolkit takes into account coulombic and nuclear elastic scattering. Nuclear reactions have been modeled by means of GEANT 4 simulations. The importance of the displacement threshold energy ([T.sub.d]) and the energy partition function is discussed. Index Terms--Atomic displacement, cross section, energy partition function, GEANT4, NIEL, threshold energy.

Comparisons are presented between measured and predicted energy deposition spectra from neutron-nuclear events within a silicon semiconductor detector. Experiment data are from irradiations performed at the TRIUMF and TSL neutron beam facilities. Predictions are based on the Geant4 radiation transport toolkit, which is applied both to quantify the effects of interactions in the detector and scattering of the neutron source by other experiments upstream of the detector. The predictions highlight the importance of quantifying scattering effects in large experiment setups, the lower-energy neutrons in the continuum of the quasi-monoenergetic spectrum suffering greater scattering. The results are used to correct neutron-induced single event upset cross-section data. Index Terms--Atmospheric radiation, neutron irradiation, pulse-height energy deposition, single event effects, single event upsets.

Quasielastic neutron scattering (QENS) is used to investigate the microscopic behavior of fresh and freeze-dried strawberry and red onion at different water contents. The results have shown that the water dynamics is promoting motions in the biological material, and it is also affected by the structure of the biological material and the microscopic properties of the biological materials are interrelated with the properties of their hydration water.

Neutron scattering spectroscopy is used to examine the dynamical behavior of water absorbed in Nafion at low hydration level as a function of temperature in the range 200-300 K. The results have emphasized the presence of a dynamical transition at around 260 K, which can be related to the temperature behavior of proton conductivity.

The neutron back scattering technique may be used to search for low-metallic land mines. An advantage of this technique is the speed of detection: the scanning speed may be made comparable to that of a metal detector. The method is sensitive to soil moisture. A limitation of the method is therefore that the soil must be sufficiently dry. The neutrons are produced with a pulsed neutron generator. An image of the back scattered thermal neutron radiation is obtained with a two dimensional position sensitive detector. Getting optimal settings for the detector system is described. The mine detection time as function of the neutron pulse parameters is investigated. Results with various dummy mines are presented. Index Terms--Land mine detection, neutron generator, neutron scattering.

Polycrystalline samples of Ln18Li8Rh5O39 (Ln = La, Pr) are synthesized by the ceramic method and characterized by X-ray and neutron diffraction. The results provide clear evidence for charge ordering between Rh(super 3+) and Rh(super 4+) in two new, stoichiometric mixed-metal oxides.

The structural changes of the crystalline lamellae and lamellar superstructures and the single chain radius of gyration of cold-drawn polyethylene, after annealing, is studied by means of combined small- and wide angle X-ray scattering and small-angle neutron scattering (SANS). It is observed that the global anisotropic shape of the chains is preserved even after prolonged annealing, and that the mobility of polyethylene chains is a local phenomenon.

The crystal structure and electronic properties of Ca2.5Sr0.5GaMn2O8 has been studied by neutron diffraction and muSR spectroscopy. The results show that short-range 2D magnetic order begins to develop within the perovskite-bilayers of MnO6 octahedra.

A pocket radiation detection system has been developed at the Idaho National Engineering and Environmental Laboratory for homeland security applications. It can detect both neutrons and gamma rays instantaneously. This sensor has been designed with an emphasis on compactness, recognizing the widespread need for a radiation detection instrument that could provide both neutron and gamma-ray detection in a single, portable unit. It is very small, extremely sensitive, versatile, and easy to operate. It can detect gamma rays and neutrons in a radiation field as low as 10 [micro]R/h above the ambient background, which makes it ideal for use in national security applications. The detection system is based on a technique of using a combination of two sensors made of lithium isotopes [sup.6]Li and [sup.7]Li. It operates on one rechargeable Li-ion battery and is small enough to be put in a pocket or clipped to a belt. In this paper, the detection technique used in developing this prototype sensor as well as its performance will be presented. Index Terms--Neutron and gamma ray, radiation detection.

Neutron storage characteristics of CaBP[O.sub.5] : [Ce.sup.3+] based phosphors have been investigated. The authors found that the CaBP[O.sub.5] : [Ce.sup.3+] phosphor shows photostimulated luminescence (PSL) by illumination with 635 nm laser light after neutron irradiation. The PSL yields of CaBP[O.sub.5] : [Ce.sup.3+] phosphor were increased by adding Ca[F.sub.2]. The green laser (532 nm) seemed to be more efficient to produce PSL signal. The phosphor might be usable in a high gamma-ray field. The fading characteristics were similar to those of a commercially available neutron imaging plate. Using a disk-like sample, a collimated neutron beam image was clearly obtained by scanning focused laser light on it. Index Terms--CaBP[O.sub.5] : [Ce.sup.3+], Ca[F.sub.2], gamma-ray sensitivity, neutron sensitivity, neutron storage phosphor.

The electromagnetic calorimeter at the BABAR detector, part of the asymmetric B Factory at SLAC, measures photons in the energy range from 20 MeV to 8 GeV with good resolution. The calorimeter is calibrated at the low-energy end with 6.13 MeV photons obtained from a liquid source system. During the calibration, a fluorine-rich liquid is activated via a neutron generator and pumped past the front of the calorimeter's crystals. Decays that occur in front of the crystals emit photons of well-defined energy, which are detected in the crystals with the regular data acquisition system. The liquid source system adds only very little material in front of the calorimeter, needs nearly no maintenance, and allows operation at the switch of a key with minimal safety hazards. This paper describes the system, presents calibration results obtained from its operation since 1999, shows the crystals' loss of light yield due to radiation damage, and shares experiences gained over the years. Index Terms--Calibration, calorimeter, CsI(TI), neutron sources, radiation damage.

Synthesis and characterization of organic spin clusters, high spin poly(arylmethyl) polyradicals with 24 and 8 triarylmethyls, are described. It is predicted that the values of S on the order of 1000 or higher may be required for 'single molecule magnet' behavior, ie, superparamagnetic blocking (via coherent rotation of magnetization) at the readily accessible temperatures T>2K.

The spin distribution in the ferromagnetically coupled hetero-bimetallic chain compound [MnNi(NO2)(sub 4)(en)(sub 2)] (en = 1,2-ethanediamine) is investigated by means of polarized neutron diffraction experiments. The spin distributions obtained from experiment and from theory are consistent and reflect a larger spin delocalization from the Ni atom due to the more covalent character of the Ni-N bonds compared to the Mn-O ones.

Neutron contribution is an important component of the secondary radiation field. For energies up to 400 MeV encompassing most of the incident spectrum for trapped protons and solar-energetic particle events, energy-angle spectra of secondary neutrons produced from the proton-induced neutron-production reaction are evaluated using the optical model for the direct reactions, the Hauser-Feshbach model for the equilibrium emission, and the exciton model for the pre-equilibrium emission, based on selected reference measurements. As a result, a good agreement has been achieved for the entire emission-energy and angle range, except for slight discrepancies at pre-equilibrium emission energies. Index Terms--Aluminum 27, energy range 400 MeV, energy-angle spectra, lead 208, proton-induced nuclear data, secondary neutrons, space-system shielding.

We discuss the application of digital pulse shape algorithms to n/[gamma] pulse shape discrimination (PSD) in boron-10 enriched liquid scintillator, where the use of digital techniques has potential applications for neutron monitors. High-speed flash analog-to-digital converters have opened up new possibilities for scintillator detector systems based upon digital event-by-event data acquisition. Using an 8-bit 1-GS/s waveform digitizer, we sampled the scintillation detector signals with nanosecond time resolution to extract event parameters such as pulse height and rise time. Hence, we have studied the variations in pulse shape and rise times for gamma rays and neutrons and the quality of separation of these events. Even using a simple 10-90% rise-time algorithm, we observe good gamma/neutron separation. We present the PSD figure-of-merit obtained using this digital technique. Index Terms--Digital signal processors, neutron detectors, pulse shaping methods.

The microstrip gas counter (MSGC) makes an excellent planar (position-sensitive) amplifier of incident electron clouds because both the anodic and cathodic gain-defining elements are produced lithographically on the same rigid substrate. We have studied the dependence of the gas gain and pulse-height resolution of the plate as a function of various geometric and gas parameters. The results show that an MSGC can be made very insensitive to the shape of the drift electrode, allowing it to be used in a wide variety of applications. An example of an electron-yield XAFS study is given. The aim of the work reported in this paper is to produce a well-defined technology platform from which to build detectors that meet the requirements of high-flux synchrotron radiation and neutron facilities, both of which are key CLRC facilities. Index Terms--Gain stability, gas gain, microstrip gas counter.

Protein thermal dynamics was evaluated by neutron scattering for halophilic malate dehydrogenase from Haloarcula marismortui (HmMalDH) and BSA under different solvent conditions. As a measure of thermal stability in each case, loss of secondary structure temperatures were determined by CD. HmMalDH requires molar salt and has different stability behavior in [H.sub.2]O, [D.sub.2]O, and in NaCl and KCl solvents. BSA remains soluble in molar NaCl. The neutron experiments provided values of mean-squared atomic fluctuations at the 0.1 ns time scale. Effective force constants, characterizing the mean resilience of the protein structure, were calculated from the variation of the mean-squared fluctuation with temperature. For HmMalDH, resilience increased progressively with increasing stability, from molar NaCl in [H.sub.2]O, via molar KCl in [D.sub.2]O, to molar NaCl in [D.sub.2]O. Surprisingly, however, the opposite was observed for BSA; its resilience is higher in [H.sub.2]O where it is less stable than in [D.sub.2]O. These results confirmed the complexity of dynamics-stability relationships in different proteins. Softer dynamics for BSA in [D.sub.2]O showed that the higher thermostability is associated with entropic fluctuations. In the halophilic protein, higher stability is associated with increased resilience showing the dominance of enthalpic terms arising from bonded interactions. From previous data, it is suggested that these are associated with hydrated ion binding stabilizing the protein in the high-salt solvent.

In the Colella-Overhauser-Wemer (COW) experiment a gravity-induced phase shift of spin 1/2 particles was detected. The experimental results were explained by using the Newtonian theory of gravity. The explanation can be easily given using general relativistic arguments and the highest order term reproduces the result of Colella, Overhauser, and Wemer together with additional, lower order corrections. The derivation can be considered as an interesting exercise for students with basic knowledge of the field of general relativity.

Research has been conducted on the high-nuclearity spin clusters exchange problem. Experiments with the constituent magnetic centers are described.

The role of neutron-induced soft errors (SE) in logic applications is examined through an experimental and analytical study of neutron-induced SE in sub-half-micron complementary metal oxide semincoductors (CMOS) SRAM and Latch circuits. Findings show that the cosmic ray neutrons affect CMOS circuits at ground level and SE rates (SER) in Latch circuits were dominated by neutrons. Moreover, neutron-induced SER in CMOS SRAM were on the same order as alpha-induced SER.

We have developed a new phoswich detector consisting of an NE213 liquid scintillator surrounded by an NE115 plastic scintillator to measure high energy neutron spectra accurately in a charged-particle mixed field. Differences in the decay time constants of light outputs from the two scintillators make it possible to separate charged-particle-induced and neutron-induced pulses. Experiments were carried out at the RIKEN and at the NIRS cyclotrons. This detector was found to be able to discriminate neutron and gamma-ray events from external-proton events. This detector will be useful to measure high energy neutron in space.