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Current medium energy gamma-ray astronomy is limited by the intense atmospheric or local background radiation degrading the sensitivity of instruments. Compton Telescopes' background rejection capabilities can be significantly improved with no loss of effective area by narrowing as much as possible the event acceptance Time of Flight (ToF) window by using fast scintillators materials such as LaBr3. We present the balloon test flight results of the FAst Compton TELescope (FACTEL) prototype we built using LaBr3 scintillators, along with other techniques to reduce the neutron induced background. This 26 hour flight from NASA's Columbia Scientific Balloon Facility at Fort Sumner, New Mexico, permitted us to evaluate the background rejection capabilities offered by our 1.2 ns ToF window compared to COMPTEL's 4 ns. We also report laboratory and Monte Carlo simulations results. We use these results to make a preliminary evaluation of the performance of a larger future instrument based on similar principles.

New scintillator materials have been shown to hold great potential for low-cost, reliable gamma-ray detectors in high-energy astronomy and solar physics. New devices for the detection of scintillation light promise to make scintillator-based instruments even more attractive by reducing mass and power requirements. In particular, silicon photomultipliers (SiPMs) are commercially available that offer gains and quantum efficiencies similar to those of photomultiplier tubes (PMTs), but with greatly reduced mass, high ruggedness, low voltage requirements, and no sensitivity to magnetic fields. SiPMs have by now been shown to perform well as readouts for scintillator gamma-ray detectors in the laboratory. Before they may used in space-based instruments, however, it must be shown that 1) sufficiently large light collecting areas may be fabricated without loss of performance; 2) the variability of the gain with temperature can be compensated for; and 3) that SiPMs are sufficiently robust and radiation hard. We present results from ongoing work to investigate whether SiPMs are appropriate for use in space, including data from the successful flight of a combined LaBr3/SiPM detector on a high-altitude scientific balloon, and the performance of larger gamma-ray spectrometers with improved light collection.

Since the launch of AGILE and FERMI, the scientific progress in high-energy (E(sub gamma) greater than approximately 200 MeV) gamma-ray science has been, and will continue to be dramatic. Both of these telescopes cover a broad energy range from approximately 20 MeV to greater than 10 GeV. However, neither instrument is optimized for observations below approximately 200 MeV where many astrophysical objects exhibit unique, transitory behavior, such as spectral breaks, bursts, and flares. Hence, while significant progress from current observations is expected, there will nonetheless remain a significant sensitivity gap in the medium-energy (approximately 0.1-200 MeV) regime; the lower end of this range remains largely unexplored whereas the upper end will allow comparison with FERMI data. Tapping into this unexplored regime requires significant improvements in sensitivity. A major emphasis of modern detector development, with the goal of providing significant improvements in sensitivity in the medium-energy regime, focuses on high-resolution electron tracking. The Three-Dimensional Track Imager (3-DTI) technology being developed at GSFC provides high resolution tracking of the electron-positron pair from gamma-ray interactions from 5 to 200 MeV. The 3-DTI consists of a time projection chamber (TPC) and 2-D cross-strip microwell detector (MWD). The low-density and homogeneous design of the 3-DTI, offers unprecedented sensitivity by providing angular resolution near the kinematic limit. Electron tracking also enables measurement of gamma-ray polarization, a new tool to study astrophysical phenomenon. We describe the design, fabrication, and performance of a 30x30x30 cubic centimeters 3-DTI detector prototype of a medium-energy gamma-ray telescope.

The Compton Gamma-Ray Observatory (C-GRO) has completed a full-sky survey during which the number of known γ-ray pulsars has more than doubled. COMPTEL has observed the classical pulsars Crab and Vela on several occasions and has derived detailed pulse patterns and spectral parameters in the 0.7-30 MeV energy interval. The new C-GROγ-ray pulsars have different properties in terms of energy spectra and light-curve shapes, and, in fact, only the Crab is seen by all four C-GRO instruments. This raises intriguing questions about the particle acceleration processes and beaming taking place in the neutron magnetosphere. We have examined the COMPTEL data to add information on these objects in the 0.7-30 MeV energy interval and present evidence for the detection of one of them, PSR B1509-58. We have also undertaken a search for candidate radio pulsars whose ephemerides are well defined. The results of these analyses are presented.Subject headings: gamma rays: observations — pulsars: general

Mass Casualty situations have historically been regarded as the lot of military medical personnel during conventional war. With the rise in the incidence of international terrorism and catastrophic natural disasters, Mass Casualty management is now the lot of civilian health care professional and will be for the foreseeable future. Appropriate systems and methods are required and are out there in the public domain. All working in health care have an obligation to be informed. Mass Casualty Triage in the military and civilian environments is fundamentally different. When faced with overwhelming casualties, the P or priority system will fail resulting in unnecessary morbidity and mortality. This is why the change from conventional Triage to Mass Casualty Triage has been recommended in the light of recent threats of international terrorist attacks. In general, all civilian Triage systems maintain an optimistic outlook in the face of Mass Casualties. In our modern cities, it is hard to visualise a total overwhelming of resources. Therefore, training is the foremost option to be prepared.

Spacecraft observations in the inner heliosphere offer the first opportunity to measure 1-10 MeV solar neutrons. We discuss the physics of low-energy neutron production in solar flares and show that, even at interacting-particle energies of 2 MeV/nucleon, neutrons with energies >10 MeV are produced. On the other hand, a significant fraction of 1-10 MeV neutrons result from interactions of >10 MeV/nucleon ions in typical flare spectra. We calculate the escaping neutron spectra for mono-energetic and power-law particle spectra at the Sun for the location and observation angle of MESSENGER at the time of its reported detection of low-energy neutrons associated with the 2007 December 31 solar flare. We detail concerns about this questionable observation of solar neutrons: 1. the inferred number of accelerated protons at the Sun for this modest M2-class flare was 10X larger than any flare observed to date, 2. the onset and duration of the 'solar' neutron count rate was similar to that of the solar energetic particles (SEPs), and 3. the authors' argument that the SEPs were dominated by electrons and so could not have produced the neutron counts locally in the spacecraft. In contrast we argue that solar energetic protons and alpha particles, through local neutron production and accidental coincidences, were the source of most of the reported 'solar-neutron' counts.

During the first part of the COMPTON Gamma Ray Observatory sky survey, COMPTEL has detected the quasars 3C273 and 3C279 and the radio galaxy Centaurus A. This paper summarizes the preliminary findings and gives an upper limit on the MeV flux of the Seyfert galaxy NGC4151.

The COMPTEL experiment on the Compton Gamma-Ray Observatory is designed to image celestial gamma radiation in the energy range from 0.75–30 MeV within a field of view of 1 steradian. It can locate stronger point sources with an accuracy better than 0.5° and is capable of mapping diffuse emission as well. The Galactic-center region was observed by COMPTEL for several 2-week periods in 1991/1992. These observations show evidence for 1.8 MeV line emission along the Galactic disk (attributed to radioactive 26 Al), extending over at least 40 degrees in longitude.

The COMPTEL experiment on GRO images 0.7 – 30 MeV celestial gamma-radiation that falls within its 1 steradian field of view. During the first fifteen months in orbit, preliminary localizations from BATSE triggers indicated that about 1 in 6 cosmic events could have fallen within COMPTEL's field of view. We summarize work on the brightest of these gamma-ray bursts and present new position constraints for GRB 911118 and GRB 920622.

The vampire bat pectoralis muscle contains at least four fiber types distributed in a nonhomogeneous pattern. One of these fiber types, here termed IIe, can be elucidated only by adenosine triphosphatase (ATPase) histochemistry combined with reactions against antifast and antislow myosin antibodies. The histochemical and immunohistochemical observations indicate a well-developed specialization of function within specific regions of the muscle. In parallel, analyses of native myosin isoforms and myosin heavy chain isoforms indicate two points. First, the histochemical “type IIe” fiber is predominant in cranial portions of the muscle, and myosin extracted from these regions exhibits a unique electrophoretic mobility not observed in the myosin isoforms of more traditional laboratory mammals. Second, the type I fibers are confined to the pectoralis abdominalis muscle and a small adjacent region of the caudal part of the pectoralis. This pattern of type I fiber distribution is considered a derived character state compared to muscle histochemical phenotype and isoform composition in the pectoralis muscles of other phyllostomids we have studied (Artibeus jamaicensis, Artibeus lituratus, Carollia perspicillata). We relate this to the unique locomotory needs of the common vampire bat, Desmodus rotundus. © 1993 Wiley-Liss, Inc.

The ability to measure solar flare neutrons by the COMPTEL γ-ray telescope on-board the Compton Gamma Ray Observatory has been demonstrated during the observations of the powerful solar flares of June 1991 from Active Region 6659. We present intensity-time profiles and count rate spectra from the impulsive X10 flare on 1991 June 19 and the prolonged X12+ flare on 1991 June 15. The emission of neutrons during the 9 June flare is coincident in time with the impulsive γ-ray emission, while the neutron emission during the 15 June flare takes place from the time of the X-ray maximum and for at least 30 minutes thereafter. The detected neutrons can also be used to image the Sun in heavy particles, the first time a celestial object has been imaged in radiation other than electromagnetic radiation.

The imaging γ-ray telescope COMPTEL on board NASA's Compton Gamma-Ray Obserrvatory has observed a number of solar flares during its first year in orbit. Of particular interest were those X-class flares associated with active region 6659 which took place on June 9, 11 and 15, 1991. COMPTEL is capable of observing solar flares both in its imaging mode (covering an energy range of 0.8-30 MeV) and in its burst mode (covering the energy range 0.1 to 10 MeV). Here we shall summarize the major results from COMPTEL regarding the γ-ray emission from these flares.

We previously reported Compton imaging measurements of 137Cs and 60Co laboratory sources using the full 15-channel readout of the Gamma-Ray Experimental Telescope Assembly (GRETA). We have since modified the detector geometry to accommodate a wider range of Compton scattering angles and implemented a neural networking method for the location of interaction positions with a 3-cm resolution inside the detector volumes. This paper describes the implementation of the neural networking method and culminates in the imaging of 137Cs, 60Co, and 252Cf sources using this technique.

We have developed, fabricated and tested a prototype imaging neutron spectrometer designed for real-time neutron source location and identification. Real-time detection and identification is important for locating materials. These materials, specifically uranium and transuranics, emit neutrons via spontaneous or induced fission. Unlike other forms of radiation (e.g. gamma rays), penetrating neutron emission is very uncommon. The instrument detects these neutrons, constructs images of the emission pattern, and reports the neutron spectrum. The device will be useful for security and proliferation deterrence, as well as for nuclear waste characterization and monitoring. The instrument is optimized for imaging and spectroscopy in the 1–20 MeV range. The detection principle is based upon multiple elastic neutron-proton scatters in organic scintillator. Two detector panel layers are utilized. By measuring the recoil proton and scattered neutron locations and energies, the direction and energy spectrum of the incident neutrons can be determined and discrete and extended sources identified. Event reconstruction yields an image of the source and its location. The hardware is low power, low mass, and rugged. Its modular design allows the user to combine multiple units for increased sensitivity. We will report the results of laboratory testing of the instrument, including exposure to a calibrated Cf-252 source. Instrument parameters include energy and angular resolution, gamma rejection, minimum source identification distances and times, and projected effective area for a fully populated instrument.

We have developed a design for a hard X-ray Compton polarimeter operating in the energy range from 50 to 500 keV, which we refer to as GRAPE (Gamma-Ray Polarimeter Experiment). We are currently preparing a balloon payload for a flight from Ft. Sumner, NM in the fall of 2011. Using a large (16-element) array of detector modules, this payload is being designed to search for polarization from known point sources of radiation, namely the Crab and Cygnus X-1. This first flight will not only provide a scientific demonstration of the GRAPE design (by measuring polarization from the Crab nebula), it will also lay the foundation for subsequent long duration balloon flights that will be designed for studying polarization from gamma-ray bursts and solar flares. Here we shall present data from calibration of the first flight module detectors and review the latest payload design.

New scintillator materials have been shown to hold great potential for low-cost, reliable gamma-ray detectors in high-energy astronomy and solar physics. Commercially available silicon photo-multipliers (SiPMs) promise to make scintillator-based instruments even more attractive by reducing mass and power requirements. SiPMs have by now been shown to perform well as readouts for scintillator gamma-ray detectors in the laboratory. We present results from ongoing work to investigate whether SiPMs are appropriate for use in space, including the Monte Carlo modeling of the light collection in a small LaBr 3 /SiPM spectrometer scheduled to fly on a high-altitude balloon flight in 2011.

We have been working on the development of a detector design for a large area coded aperture imaging system operating in the 10-600 keV energy range. The detector design is based on an array of Lanthanum Bromide (LaBr3) scintillators, each directly coupled to a Hamamatsu 64-channel multi-anode photomultiplier tube (MAPMT). This paper focuses on the development of the GEANT4-based simulations as an aid in the optimization of the detector design. The simulations have been validated by comparisons with various laboratory data sets. We will summarize the current status and latest findings from this study.

We have developed, fabricated and tested a prototype imaging neutron spectrometer designed for real-time neutron source location and identification. Real-time detection and identification is important for locating materials. These materials, specifically uranium and transuranics, emit neutrons via spontaneous or induced fission. Unlike other forms of radiation (e.g. gamma rays), penetrating neutron emission is very uncommon. The instrument detects these neutrons, constructs images of the emission pattern, and reports the neutron spectrum. The device will be useful for security and proliferation deterrence, as well as for nuclear waste characterization and monitoring. The instrument is optimized for imaging and spectroscopy in the 1-20 MeV range. The detection principle is based upon multiple elastic neutron-proton scatters in organic scintillator. Two detector panel layers are utilized. By measuring the recoil proton and scattered neutron locations and energies, the direction and energy spectrum of the incident neutrons can be determined and discrete and extended sources identified. Event reconstruction yields an image of the source and its location. The hardware is low power, low mass, and rugged. Its modular design allows the user to combine multiple units for increased sensitivity. We will report the results of laboratory testing of the instrument, including exposure to a calibrated Cf-252 source. Instrument parameters include energy and angular resolution, gamma rejection, minimum source identification distances and times, and projected effective area for a fully populated instrument.

We have developed a design for a hard X-ray Compton polarimeter operating in the energy range from 50 to 500 keV, which we refer to as GRAPE (Gamma-Ray Polarimeter Experiment). We are currently preparing a balloon payload for a flight from Ft. Sumner, NM in the fall of 2011. Using a large (16-element) array of detector modules, this payload is being designed to search for polarization from known point sources of radiation, namely the Crab and Cygnus X-1. This first flight will not only provide a scientific demonstration of the GRAPE design (by measuring polarization from the Crab nebula), it will also lay the foundation for subsequent long duration balloon flights that will be designed for studying polarization from gamma-ray bursts and solar flares. Here we shall present data from calibration of the first flight module detectors and review the latest payload design.

The field of medium-energy gamma-ray astronomy urgently needs a new mission to build on the success of the COMPTEL instrument on the Compton Gamma Ray Observatory. This mission must achieve sensitivity significantly greater than that of COMPTEL in order to advance the science of relativistic particle accelerators, nuclear astrophysics, and diffuse backgrounds, and bridge the gap between current and future hard X-ray missions and the high-energy Fermi mission. Such an increase in sensitivity can only come about via a dramatic decrease in the instrumental background. We are currently developing a concept for a low-background Compton telescope that employs modern scintillator technology to achieve this increase in sensitivity. Specifically, by employing LaBr 3 scintillators for the calorimeter, one can take advantage of the unique speed and resolving power of this material to improve the instrument sensitivity while simultaneously enhancing its spectroscopic and imaging performance. Also, using deuterated organic scintillator in the scattering detector will reduce internal background from neutron capture. We present calibration results from a laboratory prototype of such an instrument, including time-of-flight, energy, and angular resolution, and compare them to simulation results using a detailed Monte Carlo model. We also describe the balloon payload we have built for a test flight of the instrument in the fall of 2010.

The Gamma-RAy Polarimeter Experiment (GRAPE) is a concept for an astronomical, hard X-ray, Compton polarimeter operating in the 50–500 keV energy band. The instrument has been optimized for wide-field polarization measurements of transient outbursts from energetic astrophysical objects such as gamma-ray bursts and solar flares. The GRAPE instrument is composed of identical modules, each of which consists of an array of scintillator elements read out by a multi-anode photomultiplier tube (MAPMT). Incident photons Compton-scatter in plastic scintillator elements and are subsequently absorbed in inorganic scintillator elements; a net polarization signal is revealed by a characteristic asymmetry in the azimuthal scattering angles. We have constructed a prototype GRAPE module, containing a single CsI(Na) calorimeter element, which has been calibrated using a polarized hard X-ray beam and flown on an engineering balloon test flight. A full-scale scientific balloon payload, consisting of up to 36 modules, is currently under development. The first flight, a one-day flight scheduled for 2011, will verify the expected scientific performance with a pointed observation of the Crab Nebula. We will then propose long-duration balloon flights to observe gamma-ray bursts and solar flares. Introduction The Gamma-RAy Polarimeter Experiment (GRAPE) is a scintillator-based Compton polarimeter designed to observe polarized astrophysical phenomena in the hard X-ray energy band (50–500 keV). Although intended primarily for observations of bright, transient events such as gamma-ray bursts (GRBs) and solar flares, GRAPE may also be operated in a collimated, pointed mode.

Multiscale edge detection using wavelet transform maxima provides a robust method to compress information in a transient signal. We apply this method to Gamma-Ray Burst (GRB) time series data from the Compton Gamma Ray Observatory (CGRO). This provides a method to quantify the variability, identify structures, significantly suppress noise and compress the volume of data by as much as a factor of 10.

The Gamma-RAy Polarimeter Experiment (GRAPE) is a concept for an astronomical hard X-ray Compton polarimeter operating in the 50 - 500 keV energy band. The instrument has been optimized for wide-field polarization measurements of transient outbursts from energetic astrophysical objects such as gamma-ray bursts and solar flares. The GRAPE instrument is composed of identical modules, each of which consists of an array of scintillator elements read out by a multi-anode photomultiplier tube (MAPMT). Incident photons Compton scatter in plastic scintillator elements and are subsequently absorbed in inorganic scintillator elements; a net polarization signal is revealed by a characteristic asymmetry in the azimuthal scattering angles. We have constructed a prototype GRAPE module that has been calibrated at a polarized hard X-ray beam and flown on an engineering balloon test flight. A full-scale scientific balloon payload, consisting of up to 36 modules, is currently under development. The first flight, a one-day flight scheduled for 2011, will verify the expected scientific performance with a pointed observation of the Crab Nebula. We will then propose long-duration balloon flights to observe gamma-ray bursts and solar flares.

Gamma-ray astronomy in the MeV range suffers from weak fluxes from sources and high background in the nuclear energy range. The background comes primarily from neutron-induced gamma rays, with the neutrons being produced by cosmic-ray interactions in the Earth's atmosphere, the spacecraft, and the instrument. Compton telescope designs often suppress this background by requiring coincidences in multiple detectors and a narrow time-of-flight (ToF) acceptance window. The COMPTEL experience on the Compton Gamma Ray Observatory shows that a 1.9-ns ToF resolution is insufficiently narrow to achieve the required low background count rate. Furthermore, neutron interactions in the detectors themselves generate an irreducible background. By employing LaBr3 scintillators for the calorimeter, one can take advantage of the unique speed and resolving power of the material to improve the instrument sensitivity and simultaneously enhance its spectroscopic performance and thus its imaging performance. We present a concept for a balloon- or space-borne Compton telescope that employs deuterated liquid in the scattering detector and LaBr3 as a calorimeter and estimate the improvement in sensitivity over past realizations of Compton telescopes. We show initial laboratory test results from a small prototype, including energy and timing resolution. Finally, we describe our plan to fly this prototype on a test balloon flight to directly validate our background predictions and guide the development of a full-scale instrument.

SONNE, the SOlar NeutroN Experiment proposed for Solar Probe Plus, is designed to measure solar neutrons from 1-20 MeV and solar gammas from 0.5-10 MeV. SONNE is a double scatter instrument that employs imaging to maximize its signal-to-noise ratio by rejecting neutral particles from non-solar directions. Under the assumption of quiescent or episodic small-flare activity, one can constrain the energy content and power dissipation by fast ions in the low corona. Although the spectrum of protons and ions produced by nanoflaring activity is unknown, we estimate the signal in neutrons and γ−rays that would be present within thirty solar radii, constrained by earlier measurements at 1 AU. Laboratory results and simulations will be presented illustrating the instrument sensitivity and resolving power.

Gamma-ray astronomy in the MeV range suffers from weak fluxes from sources and high background in the nuclear energy range. The background comes primarily from neutron-induced gamma rays with the neutrons being produced by cosmic-ray interactions in the Earth's atmosphere, the spacecraft and the instrument. Compton telescope designs often suppress this background by requiring coincidences in multiple detectors and a narrow time-of-flight (ToF) acceptance window. The COMPTEL experience on the Compton Gamma Ray Observatory shows that a 1.5-ns ToF window is insufficiently narrow to achieve the required low background count rate. Furthermore, neutron interactions in the detectors themselves generate an irreducible background. Judicious choices of instrument materials and new spacecraft designs improve the situation. However, large gains come from new scintillator technology that combines intrinsic neutron insensitivity with exceptional speed to reduce the instrument background rate by upwards of 90%, thereby greatly improving the sensitivity of searches and measurements, while simultaneously improving energy and angle resolution.

The Fast Neutron Imaging Telescope (FNIT) instrument is a NA-22 funded project for the design, construction, calibration and modeling of an instrument specifically tailored to measure and identify sources of fission neutrons - a key signature of Special Nuclear Material (SNM). A neutron detector that is sensitive to this energy range is of utmost importance to stop the proliferation of these materials. The proof of concept of this instrument has been successfully demonstrated with a limited FNIT prototype. After being constructed and fine-tuned at the University of New Hampshire (UNH), the prototype was calibrated with quasi-monoenergetic neutron beams at Crocker Nuclear Laboratory. Extensive Monte Carlo calculations are currently in the advance stages for the modeling of FNIT. These simulations, along with the calibration and tests that have been performed with a 252Cf source at UNH, will be used to determine the instrument efficiency and response. Further instrument simulations will allow us to determine the best methods for spectral and imaging de-convolution. Ultimately, these methods will be implemented into “on-line” software being designed for real-time analysis algorithms to be used in conjunction with a fully populated, portable neutron telescope. We present the most recent laboratory and instrument modeling results.

The essence of conflict is the actual or implied use of violence. Recovery implies a return to a previous state. Recovery may be rapid (measured in days or months) or may take many years. What may be called the onset of recovery varies – it may begin almost immediately during the acute phase of a conflict or catastrophe. The immediate provision of food, water, sanitation and shelter via humanitarian efforts in the first days is an illustration of a very early manifestation of conflict recovery. However, the process typically begins in the postemergency phase, when a degree of stability and safety allows a more comprehensive approach.

The morphology of the glans penis is described for Mormopterus jugularis, Molossops planirostris, M. temminckii, Nyctinomops laticaudatus, N. macrotis, Tadarida aegyptiaca , and T. brasiliensis . The glans penis is stout, elongate, and pendulous in all seven species. The external surface of the glans is covered with epithelial spines in all species except T. brasiliensis , where spines are replaced by rows of epithelial papillae. Epithelial spines range in size from 100 µm in M. jugularis . The urinary meatus is subterminal and covered by a prominent urethral cap in all species examined except the two species of Molossops . A small os penis is present at the distal terminus of the corpora cavernosa in M. jugularis, N. laticaudatus , and T. brasiliensis . The corpora cavernosa is restricted to the proximal one-half of the glans and no os penis was found in either species of Molossops . Although molossids exhibit only modest intraspecific variation in penile morphology, considerable intergeneric variation is present making these morphological characters potentially useful for testing phylogenetic hypotheses.

The Milagro Gamma Ray Observatory, a ground-based water Cherenkov detector designed primarily for observing very high energy gamma ray sources, can also be used to study the Sun. Measurements of high energy emission from solar flares can lead to an understanding of the solar energetic particle acceleration mechanism(s), and Milagro, with enhanced data acquisition electronics, will measure solar cosmic rays in the poorly studied energy range from 10 to 300 GeV. Monte Carlo simulations show that proton and neutron solar cosmic rays at these energies will be detectable at the ground level through the single muons and/or mini showers they produce. Milagro can detect these events in a scaler counting mode similar to that of a neutron monitor. Additionally, it can operate in a telescope mode that reduces background by pointing at the source region. We also report a preliminary detection, using the Milagro prototype, Milagrito, of a ground level event (GLE) on 6 November 1997 associated with an X-class solar flare.

The Gamma-RAy Polarimeter Experiment (GRAPE) is a concept for an astronomical hard X-ray Compton polarimeter operating in the 50 - 500 keV energy band. The instrument has been optimized for wide-field polarization measurements of transient outbursts from energetic astrophysical objects such as gamma-ray bursts and solar flares. The GRAPE instrument is composed of identical modules, each of which consists of an array of scintillator elements read out by a multi-anode photomultiplier tube (MAPMT). Incident photons Compton scatter in plastic scintillator elements and are subsequently absorbed in inorganic scintillator elements; a net polarization signal is revealed by a characteristic asymmetry in the azimuthal scattering angles. We have constructed a prototype GRAPE module containing a single CsI(Na) calorimeter element, at the center of the MAPMT, surrounded by 60 plastic elements. The prototype has been combined with custom readout electronics and software to create a complete "engineering model" of the GRAPE instrument. This engineering model has been calibrated using a nearly 100% polarized hard X-ray beam at the Advanced Photon Source at Argonne National Laboratory. We find modulation factors of 0.46 +/- 0.06 and 0.48 +/- 0.03 at 69.5 keV and 129.5 keV, respectively, in good agreement with Monte Carlo simulations. In this paper we present details of the beam test, data analysis, and simulations, and discuss the implications of our results for the further development of the GRAPE concept., 35 pages, 14 figures, accepted for publication in NIM-A

An analysis of 7 years of Milagro data performed on a 10-degree angular scale has found two localized regions of excess of unknown origin with greater than 12 sigma significance. Both regions are inconsistent with gamma-ray emission with high confidence. One of the regions has a different energy spectrum than the isotropic cosmic-ray flux at a level of 4.6 sigma, and it is consistent with hard spectrum protons with an exponential cutoff, with the most significant excess at ~10 TeV. Potential causes of these excesses are explored, but no compelling explanations are found., Submitted to PhysRevLett

New scintillator materials have recently been shown to hold great potential for low-cost, reliable gamma-ray detectors in high-energy astronomy. New devices for the detection of scintillation light promise to make scintillator-based instruments even more attractive by reducing mass and power requirements. In particular, silicon photo-multipliers (SiPMs) are starting to become commercially available that offer gains and quantum efficiencies similar to those of photo-multiplier tubes (PMTs), but with greatly reduced mass, high ruggedness, low voltage requirements, and no sensitivity to magnetic fields. We have conducted laboratory tests of a sample of commercially available SiPMs coupled to LaBr 3 :Ce, a scintillator of relevance to future high-energy astrophysics missions. We present results for gamma-ray spectroscopy, compare the SiPM performance to that of a PMT, and discuss the extent to which SiPMs offer significant advantages for scintillator-based space missions.

Optical turbulence is an important characteristic for laser propagation in the atmosphere. The optical turbulence causes refractive index fluctuations in the air. The accumulative atmospheric refractive index fluctuations can incur deleterious effects to a laser beam propagating in the atmosphere by distorting its wavefront. Accurate characterization of turbulence in the atmosphere is important to many light propagation studies and related applications. Temperature fluctuations/turbulences in the atmosphere are highly correlated with the atmospheric optical turbulence. In many occasions, optical turbulences profiles in the atmosphere were obtained through the measurements of temperature turbulence and other other atmospheric quantities, for example, air humidity. Therefore determination of temperature fluctuations/turbulences parameter C 2 T is helpful to the measurement of optical turbulence. Thermosonde was commonly seen in measurements of C 2 T in the past. Here we show that a direct lidar system is able to fulfill the task of C 2 T measurements. And compared to the thermosonde measurements the proposed lidar method has many advantages.

Diffuse $\gamma$-ray emission produced by the interaction of cosmic-ray particles with matter and radiation in the Galaxy can be used to probe the distribution of cosmic rays and their sources in different regions of the Galaxy. With its large field of view and long observation time, the Milagro Gamma Ray Observatory is an ideal instrument for surveying large regions of the Northern Hemisphere sky and for detecting diffuse $\gamma$-ray emission at very high energies. Here, the spatial distribution and the flux of the diffuse $\gamma$-ray emission in the TeV energy range with a median energy of 15 TeV for Galactic longitudes between 30$^\circ$ and 110$^\circ$ and between 136$^\circ$ and 216$^\circ$ and for Galactic latitudes between -10$^\circ$ and 10$^\circ$ are determined. The measured fluxes are consistent with predictions of the GALPROP model everywhere except for the Cygnus region ($l\in[65^\circ,85^\circ]$). For the Cygnus region, the flux is twice the predicted value. This excess can be explained by the presence of active cosmic ray sources accelerating hadrons which interact with the local dense interstellar medium and produce gamma rays through pion decay., Comment: 15 pages, 3 figures, accepted by ApJ

The spare detectors from NASA's Compton Gamma-Ray Observatory COMPTEL instrument have been reconfigured to demonstrate the capability at ground level to remotely locate and identify sources of gamma radiation. The Gamma-Ray Experimental Telescope Assembly (GRETA) employs two 28 cm diameter scintillation detectors separated by 81 cm: one 8.5 cm thick liquid scintillator detector and one 7.5 cm thick Nal(Tl) detector. The assembly electronics and real-time data acquisition system measures the energy deposits and time-of-flight for each coincident detection and compiles histograms of total energy and incident angle as computed using the kinematics of Compton scattering. GRETA's field of view is a cone with full angle approximately 120deg. The sensitive energy range is 0.3 to 2.6 MeV. Energy resolution is ~10% FWHM. The angular resolution, ~15deg in the simplified configuration tested, will improve to better than 5deg with well-defined enhancements to the data acquisition hardware and data analysis routines. We conducted a series of laboratory demonstrations to characterize the performance of the GRETA detector. Following detector characterization, we demonstrate GRETA 's ability to locate and identify an unknown source and position within its field of view. In this scenario, the location and isotope-identifying energy spectrum of an 800 muCi137 Cs source 10 meters from the instrument with two intervening walls was determined in less than one minute. We will present further details of the instrument design and the measurements.

We describe the development, testing and performance of a Fast Neutron Imaging Telescope (FNIT) with the capability of detecting and composing real-time images of a neutron source. A key signature unique to Special Nuclear Material (SNM) is the emission of fission neutrons. An efficient neutron detector that is sensitive to neutrons in the energy range of 1-10 MeV and with imaging capability represents a key tool for the interdiction of smuggling of clandestine amounts of SNM into the country. A small, modular, organic liquid scintillator detector - initially developed at the University of New Hampshire to study solar neutrons - has been tailored to locate fission neutron sources in homeland security applications. The principle of detection is based on multiple elastic neutron-proton scattering. By measuring the interaction locations and the recoil proton energies, we can determine the direction and energy spectrum of the primary neutron flux along with the location of the neutron source. Key parameters determined in the laboratory thus far have been an energy (trigger) threshold of 200 keV (proton equivalent) and a 5deg (sigma) angular resolution across a broad energy range. This paper outlines the most recent results on instrument development, the FNIT detector's response to SNM and real-time neutron imaging development.

The acceleration and trapping of protons necessary to explain long duration, high energy, gamma-ray solar flares is modeled as a single process within a coronal loop, where an injected proton spectrum is transported and accelerated by MHD turbulence. The loop is modeled as a leaky box where second-order Fermi-acceleration is a result of the turbulence. Protons accelerated in the coronal loop escape from the ends of the loop (precipitation) into the chromosphere or lower corona where they produce gamma-ray emission. The model provides a method for computing the proton spectrum as it evolves from an initial power law under coupled spatial and momentum diffusion. With reasonable coronal parameters the model yields time-extended relativistic proton precipitation, which peaks up to several hundred seconds after injection. Momentum diffusion is inversely proportional to spatial diffusion for an assumed Alfven wave field within the coronal loop. Assuming a magnetic field on the order of 100 G, δB/B need only be a few percent if the loop is 105 km in length in order to describe the temporal behavior of the high-energy gamma-ray flare of 3 June 1982.

FNIT (the Fast Neutron Imaging Telescope), a detector with both imaging and energy measurement capabilities, sensitive to neutrons in the range 0.8-20 MeV, was initially conceived to study solar neutrons as a candidate design for the Inner Heliosphere Sentinel (IHS) spacecraft of NASA’s Solar Sentinels program and successively reconfigured to locate fission neutron sources. By accurately identifying the position of the source with imaging techniques and reconstructing the Watt spectrum of fission neutrons, FNIT can detect samples of special nuclear material (SNM), including heavily shielded and masked ones. The detection principle is based on multiple elastic neutron-proton scatterings in organic scintillators. By reconstructing n-p event locations and sequence and measuring the recoil proton energies, the direction and energy spectrum of the primary neutron flux can be determined and neutron sources identified. We describe the design of the FNIT prototype and present its energy reconstruction and imaging performance, assessed by exposing FNIT to a neutron beam and to a Pu fission neutron source. Keywords: fast neutrons, neutron imaging, passive SNM search, container screening 1. INTRODUCTION A critical gap in national security is the inability to efficiently detect and identify problematic quantities of Special Nuclear Material (SNM). These materials, specifically uranium and transuranics, emit neutrons via spontaneous or induced fission. Unlike the other forms of radiation produced by SNM (e.g. -rays), copious and penetrating neutron emission is unique to fissionable material. From a practical point of view, shielding of fission neutrons ( e.g. in a cargo container) represents a far greater challenge and requires a considerably larger and heavier amount of passive material than shielding of other forms of radiation emitted by SNM. Neutron detection, therefore, is of particular interest for SNM identification for security and proliferation deterrence, as well as for nuclear waste detection and monitoring. While improvements in all forms of radiation detection are necessary to close the SNM security gap, there are unique problems associated with the detection and measurement of neutrons. Some of these are: • current neutron detectors used in the field ( e.g. Bonner spheres

The spare detectors from NASA Compton Gamma-Ray Observatory COMPTEL instrument have been reconfigured to demonstrate the capability at ground level to remotely locate and identify sources of g radiation or the movement of material that might shield γ-ray sources. The Gamma-Ray Experimental Telescope Assembly (GRETA) employs two 28 cm diameter scintillation detectors separated by 81 cm: one 8.5 cm thick liquid scintillator detector and one 7.5 cm thick NaI(Tl) detector. The assembly electronics and real-time data acquisition system measures the energy deposits and time-of- flight for each coincident detection and compiles histograms of total energy and incident angle as computed using the kinematics of Compton scattering. The GRETA field of view is a cone with full angle approximately 120°. The sensitive energy range is 0.3 to 2.6 MeV. Energy resolution is ~10% FWHM. The angular resolution, ~19° in the simplified configuration tested, will improve to better than 5° with well-defined enhancements to the data acquisition hardware and data analysis routines. When operated in the mode that was used in space, the instrument is capable of measuring and imaging up to 30 MeV with an angular resolution of 1.5°. The response of the instrument was mapped in the laboratory with 14 Ci 22 Na source 3 m from the instrument. Later, we conducted demonstrations under two measurement scenarios. In one, the remotely located instrument observed an increase of background radiation counts at 1.4 MeV when a large amount of lead was removed from a building and a corresponding decrease when the lead was replaced. In the other scenario, the location and isotope-identifying energy spectrum of a 500 μCi 137 Cs source 3-5 m from the instrument with two intervening walls was determined in less than one minute. We report details of the instrument design and these measurements.

Illicit nuclear materials represent a threat for the safety of the American citizens, and the detection and interdiction of a nuclear weapon is a national problem that has not been yet solved. Alleviating this threat represents an enormous challenge to current detection methods that have to be substantially improved to identify and discriminate threatening from benign incidents. Rugged, low-power and less-expensive radiation detectors and imagers are needed for large-scale wireless deployment. Detecting the gamma rays emitted by nuclear and fissionable ma terials, particularly special nuclear materials (SNM), is the most convenient way to identify and locate them. While there are detectors that have the necessary sensitivity, none are suitable to meet the present need, primarily because of the high occurrence of false alarms. The exploitation of neutron signatures represents a promising solution to detecting illicit nuclear materials. This work presents the development of several detector configurations such as a mobile active interrogation system based on a compact RF-Plasma neutron generator developed at LBNL and a fast neutron telescope that uses plastic scintillating-fibers developed at the University of New Hampshire. A human-portable improved Solid-State Neutron Detector (SSND) intended to replace pressurized

Background Each year in the UK 2000 children attend emergency departments and 500 are admitted to hospital following a bath water scald. The long term effects can include disability, disfigurement or psychological harm and repeated skin grafts may be required as the child grows. The costs of treating a severe scald are estimated at 250,000 GBP. Children living in the most deprived wards are at greatest risk of thermal injuries; hospital admission rates are three times that for children living in the least deprived wards. Domestic hot water, which is usually stored at around 60 degrees Celsius, can result in a second-degree burn after 3 seconds and a third-degree burn after 5 seconds. Educational strategies to encourage testing of tap water temperature and reduction of hot water thermostat settings have largely proved unsuccessful. Legislation in the USA mandating pre-setting hot water heater thermostats at 49 degrees Celsius was effective in reducing scald injuries, suggesting passive measures may have a greater impact. Thermostatic mixer valves (TMVs), recently developed for the domestic market, fitted across the hot and cold water supply pipes of the bath, allow delivery of water set at a fixed temperature from the hot bath tap. These valves therefore offer the potential to reduce scald injuries. Design/Methods A pragmatic, randomised controlled trial to assess the effectiveness of TMVs in reducing bath hot tap water temperatures in the homes of families with young children in rented social housing. Two parallel arms include an intervention group and a control group where the intervention will be deferred. The intervention will consist of fitting a TMV (set at 44 degrees Celsius) by a qualified plumber and provision of educational materials. The control arm will not receive a TMV or the educational materials for the study duration but will be offered the intervention after collection of follow-up data 12 months post randomisation. The primary outcome measure will be the bath hot tap water temperature. Fifteen families per arm are required to detect a reduction in the mean bath hot tap water temperature from 60.4 degrees Celsius (SD 9.1) in the control group to 46 degrees Celsius in the intervention group, with 90% power and a 5% significance level (2 sided). Secondary outcome measures including acceptability will require a sample size of 120 participants. Discussion Whilst TMVs have the potential to reduce scald injuries, to date there have been no randomised controlled trials assessing their effectiveness, acceptability and cost effectiveness. Trial Registration ISRCTN21179067

Protons and Ions are accelerated in flares. Some of them can escape and be detected as so‐called impulsive SEPs, but most of our knowledge of these particles comes from the secondary neutral radiation they emit when they interact in the low corona or photosphere. The γ‐ray and neutron emissions sample different parts of these populations, both in energy and composition. We review the wide variety of population behavior and nature that is revealed via the neutral emissions. These include rapid acceleration, prolonged high‐energy acceleration, a sometimes rapidly evolving spectrum, transport effects, the relationship with electrons and unusual compositions. We review highlights of missions including SMM, CGRO and RHESSI and ground based measurements. We also look ahead to future measurements of γ rays and neutrons on Solar Orbiter and Solar Sentinels and what may be discovered.

This study explores the cultural contribution to emotional responses. Specifically, it examines the contribution of social structures to the severi ty of aggression in sexual jealousy situations. It is hypothesized that the aggression in jealousy situations is correlated with the cultural importance attached to being married, the limitations placed on nonmarital and extra marital sexual gratification, the emphasis on private ownership of proper ty, and the requirement of personal descendants. The social structures and behavioral patterns that are associated with these variables were rated in 92 preindustrial societies and correlated with the aggressiveness of the responses of men and women in jealousy situations. Stepwise multiple regression analyses on the male data revealed that the social structures and behavioral patterns that are associated with pair-bonding, sexual grat ification, and property accounted for 29 percent of the variance of the responses in jealousy situations. The contribution of the behavioral pat terns that are associated with personal descendants was negligible. None of the variance of the female responses was accounted for by the cultural variables. The latter finding was attributed to the limited options that are available to women for coping with unfaithful men.