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The Advanced Compton Telescope (ACT), NASA’s next major step in gamma‐ray astronomy, will probe the fires where chemical elements are formed by enabling high‐resolution spectroscopy of nuclear emission from supernova explosions. During the past several years, our collaboration has been undertaking a NASA mission concept study for ACT. This study was designed to (1) transform the key scientific objectives into specific instrument requirements, (2) to identify the most promising technologies to meet those requirements, and (3) to design a viable mission concept for this instrument. We will present the results of this study, including scientific goals, instrument design, and mission requirements.

GLAST LAT will detect several solar flares in gamma rays. Motivated by the CGRO results on neutrons emitted during a solar flare, we try to estimate the possibility of the LAT to detect solar neutrons. Besides gamma rays, neutrons could indeed interact in the LAT instrument and mimic a gamma‐ray signal. An estimate of the contamination of gamma‐ray detection in solar flares by the neutron component is given.

A golden age of GRB astronomy will be upon us when GLAST launches in late 2007 and Swift continues its mission. The Swift NASA MIDEX launched in November 2004 and is detecting ∼100 gamma‐ray bursts (GRBs) each year. For almost every burst there is a prompt (within ∼90 s) spacecraft repointing to give X‐ray and UV/optical observations of the afterglow. Swift has already collected an impressive database, including prompt emission to higher sensitivities than BATSE, uniform monitoring of afterglows, and rapid follow‐up by other observatories notified through the GCN. With the launch of GLAST, there will be the opportunity to combine the powers of Swift and GLAST to make tremendous progress in the study of GRBs. GRBs detected by either mission will trigger observation by the other to give multiwavelength data on prompt and afterglow emission from optical through GeV gamma rays. This paper summarizes scientific results from Swift and CGRO/EGRET and discusses the ways that Swift and GLAST can work together on GRB observations.

Rapid follow‐up of gamma‐ray burst (GRB) afterglows with the multi‐wavelength satellite Swift and other instruments is shedding new light on GRB. This is leading to a reappraisal and expansion of the standard model of the GRB early afterglow behavior and its connection to the prompt gamma‐ray emission. New information in the previously poorly known time range from minutes to hours has revealed characteristic properties of the X‐ray light curves, including steep decays followed by shallow decays and flares. Other discoveries include the localization and follow‐up of short GRB afterglows, localizing long bursts beyond the z≳6 redshift range, the detection of prompt optical/IR emission while the burst is still emitting gamma‐rays, the detection and prompt follow‐up of supernovae associated with GRB, and challenges to the traditional short‐long classification. We review some of the current theoretical interpretations of these new phenomena.

The Minimal Spanning Tree (MST) algorithm is a graph‐theoretical method of finding clusters in a given set of points. We apply MST to gamma‐ray bidimensional images and associate possible sources with the regions where photons’ arrival directions clusterize. Additional filters to select clusters are included to reduce spurious detections. We present some applications to simulated GLAST data.

We summarize some results obtained in recent years by the Whole Earth Blazar Telescope (WEBT) to highlight its potential and describe its observing strategy to support GLAST observations.

Using MCNP5 code, we modeled an existing coded-aperture, gamma-ray imaging system in order to optimize the thicknesses of its mask and detector elements. We also explored the feasibility of designing an active-mask version of the instrument where the lead elements of the mask are replaced by alkali-halide detectors. The results of these simulations indicate that increasing the detector thickness will improve the instrument's sensitivity, but, surprisingly, the active-mask system is only slightly more sensitive than the passive version.

Since the beginning of its operation in April 2005, the MAGIC telescope was able to observe ten different GRB events since their early beginning, even while the prompt emission was still ongoing. Observations, with energy thresholds spanning between 80 and 300 GeV, did not reveal any γ‐ray emission. We present a direct determination of the MAGIC sensitivity in GRB mode and the upper limits for the ten follow‐up observations. At energies around 100 GeV, MAGIC is currently the fastest and most sensitive operational GRB detector in the world.

We measured temperature dependence of alpha/gamma-ratio of three sample pieces of Ce 0.5 mol% doped Gd2SiO5 crystalline scintillator, which are cut from different ingots and have a dimension of 24times24times5 mm3. The temperature is controlled by a heat bath within plusmn0.5 K at +20, 0, and -20 degrees of Celcius. By using intrinsic activity of 152Gd 2.14 MeV alpha-ray, it is irradiated uniformly inside the scintillator. To determine alpha/gamma-ratio precisely, we measured input energy and pulse height linearity between 60 keV and 511 keV, at three temperature conditions. Then, we measure the alpha-ray response of the scintillator by a passive rejection any outer backgrounds by Pb and Sn blocks. As a result, alpha/gamma-ratio of 0.5 mol% Ce doped GSO is turned out to be ~0.175, and it showed a gradual temperature dependence of ~0.4 keV/K.

We present observations of GRB 060108, the 100th burst detected by Swift. The optical afterglow was found to be below UVOT detection limits within the first 100 s, and the ratio of X‐ray and R band measurements at ∼ 1000 s after the trigger gives a spectral index βOX = 0.45, which makes this burst “dark” according to the Jakobbson classification. We derive a maximum photometric redshift of z

The Gamma‐ray Large Area Space Telescope (GLAST) will observe the gamma‐ray sky in the MeV and GeV energy range. It will detect a number of gamma‐ray bursts (GRBs) every year, depending on their emission at high energies, which is still unknown. GLAST will be the first instrument observing GRBs at energies above 20 GeV. A systematic study prior to launch, which is foreseen for 15 November 2007, was the GLAST Data Challenge 2 (DC 2). For GLAST DC 2 two month of data taking were simulated. Based on these simulations the GRB Working Group performed systematic studies of the performance of GLAST in observing GRBs. These studies included the spectral analysis of the prompt emission, a position fit of the GRB, and the search for prompt and afterglow emissions in the LAT data.

We report on how the the GLAST Burst Monitor (GBM) Flight Software will detect gamma‐ray rate increases, a process known as “triggering”, and on how the Flight Software will locate and classify the causes of the triggers.

We present here the analysis of the early and late multiwavelength afterglow emission, as observed by Swift a small robotic telescope, and the VLT. We compare early observations with late afterglow observations obtained with Swift and the VLT and we observe an intense rebrightening in the optical band at about one day after the burst which is not present in the X‐ray band. The lack of detection in X‐ray of such a strong rebrightening at lower energies may be described with a variable external density profile. In such a scenario, the combined X‐ray and optical observations allow us to derive that the matter density located at ∼ 1017 cm from the burst is about a factor of 10 higher than in the inner region. This is the first time in which a rebrightening has been observed in the optical afterglow of a GRB that is clearly absent in the X‐ray afterglow.

We provide an overview of the GLAST Guest Investigator (GI) program, which will support basic research relevant to the GLAST mission in yearly cycles beginning approximately two months after launch. Current details about the GLAST GI program will always be posted on the GLAST Science Support Center (GSSC) website: http://glast.gsfc.nasa.gov/ssc/.

At the end of the EGRET mission, only 6 Galactic sources in the 3rd EGRET catalog had firm identifications: 5 young pulsars and a solar flare. Another dozen or so had plausible counterparts. Now, at the dawn of the GLAST era, around 30 sources detected at other wavelengths have been identified as probable or plausible counterparts. These include nearly all of the sources with significant emission above 1 GeV, which will be the sources GLAST will best be able to study. I review the current status of our knowledge of these sources based on radio, infrared, and X‐ray data. These Galactic sources are destined to be the first sources firmly identified by GLAST.

The LAT Instrument Science Operations Center (ISOC) will perform various tasks to support coordination of multiwavelength observations for transient sources. In this paper, we describe the prototype implementation of the Automated Science Processing (ASP) for the detection and analysis of gamma‐ray bursts (GRBs) in LAT and GBM data. The GRB‐related tasks include: position refinement using LAT data given initial GBM or GCN locations, spectral analysis using LAT data alone, joint spectral fitting with GBM data, gamma‐ray afterglow detection and characterization, and blind searches for prompt burst emission in LAT data.

A virtual laboratory via internet to provide a highly iterative and powerful teaching tool for scientific and technical discipline is given. The experimenter takes advantage of a virtual laboratory and he can execute nuclear experiment at introductory level e.g. Gamma ray detection with Geiger‐Muller Counter at remote location using internet communication technology.

During its first cycle, the MAGIC (Major Atmospheric Gamma‐ray Imaging Cherenkov) telescope was performing an observational campaign covering a total of about 250 hours on galactic sources. Here we review the results for the very high energy (> 100 GeV) γ‐ray emission from some of those sources. We focus on LS I +61 303 and PSR 1951+32.

The Gamma‐ray Large Area Space Telescope, GLAST, is a mission to measure the cosmic gamma‐ray flux in the energy range 20 MeV to > 300 GeV, with supporting measurements for gamma‐ray bursts from 8 keV to 30 MeV. With its launch in late 2007, GLAST will open a new and important window on a wide variety of high‐energy phenomena, including black holes and active galactic nuclei, gamma‐ray bursts, the origin of cosmic rays and studies of supernova remnants, and searches for hypothetical new phenomena. Along with the major science questions for GLAST, this talk will include the mission status, operations plans, and the opportunities for Guest Investigators.

The signal shapes produced by alpha and X-ray radiation in 2 mm thick CdZnTe detectors have been measured. The signals produced in a single large pad detector and a 300 mum pixilated detector have been compared. The influence of the small pixel effect and it's variation with detector bias is visible. Synopsys Sentaurus TCAD is used to simulate the charge carrier motion in the detectors and is compared against the measured signals. A description of how the simulations will aid detector design with optimal pixel size, inter-pixel spacing and bias voltage is included.

The results of alpha, beta, gamma global activity measurements and gamma spectrometric measurements are presented. For more detailed characterization of samples, gamma‐spectrometric measurement, implying identification of radionuclides and their activities are carried‐out on significant ambiental annual samples.

High-energy gamma-ray sources are inherently nonthermal, multiwavelength objects. With the launch of the Gamma-ray Large Area Space Telescope (GLAST) scheduled for later this year, the GLAST Large Area Telescope (LAT) Collaboration invites cooperative efforts from observers at all wavelengths. Among the many topics where multiwavelength studies will maximize the scientific understanding, two stand out for particular emphasis: (1) Active Galactic Nuclei. The study of AGN gamma-ray jets through time variability and spectral modeling can help link the accretion processes close to the black hole with the large-scale interaction of the AGN with its environment; (2) Unidentified Gamma-ray Sources. New gamma-ray sources need first to be identified with known objects seen at other wavelengths using position, spectrum, or time variability, and then multiwavelength studies can be used to explore the astrophysical implications of high-energy radiation from these sources. Observers interested in any type of coordinated observations should contact the LAT Multiwavelength Coordinating Group.

The poster presents a set of simple tools being developed to predict GLAST’s performance for specific cases, like the accumulation time needed to reach a given significance or statistical accuracy for a particular source. Different examples are given, like the generation of a full‐sky sensitivity map.

The Electron Multiplying CCD (EMCCD) astronomical camera, under development at the Institute of Astronomy UNAM, will be able to obtain images of faint optical objects with very low instrumental noise and short integration times. The EMCCD is a normal CCD with an additional multiplication register located before the input of the readout amplifier. This will be a very suitable instrument to search for optical pulsations of unidentified gamma‐ray sources, specially with GLAST entering the realm of radio quiet gamma‐ray loud pulsars.

An example of wavelet transforms applied to data from EGRET and data of the GLAST pre‐launch simulations is reported. 1D wavelet transform can be an useful tool in the analysis of gamma‐ray source variability, while 2D/3D wavelet transform is a potential partner tool of the standard Likelihood analysis, in the frame of gamma‐ray source detection.

Gamma ray spectroscopy has been successfully applied as a survey tool in the fields of morphology, geology and mineral exploration. Gamma ray surveys are regularly done at ground level, which frequently requires transecting remote and unforgiving environments. Thus a need for the development of a transportable, robust and portable gamma ray detection system was identified. In addition to collecting radiation data, such a system was required to also provide the geographic position of the data and allow for various analyses tools to be utilised in the field. These functions were achieved by integrating a USB-driven scintillation detector with a field tablet and creating software to control acquisition and analyses of radiation data, as well as logging position. The system was tested in different geographical locations under different modes of transport. The instrument was tested by employing several different methods of data analysis in order to extract natural nuclide condensations. The consistency in the obtained data demonstrated the reliability of the instrument in the different environments. The system also successfully replicated previous radio-element survey findings and provided information on several geographical phenomena, including information on the geology, paved road structure and beach sediment characteristics.

The Electromagnetic Calorimeter of the CMS experiment has been designed to achieve an extreme precision in photon and electron energy measurements at LHC. The status of the project will be discussed, together with recent results on performances of final components in beam tests.

We present results from the initial testing of arrays of cryogenic microcalorimeter gamma-ray detectors. The successful fabrication and multiplexed operation of these arrays allow us to make pixel-to-pixel performance comparisons. The relationship between operating conditions and array performance is investigated. Advanced refrigerators for these detectors work without liquid cryogens, achieve temperatures below 100 mK, and operate continuously for many days.

This paper demonstrates the feasibility of a portable gamma radiation monitoring system, based on the Anderson current loop circuit, where nickel oxide (NiO) thick films are used as radiation-sensing elements. A cost effective prototype system was developed for remote ionising radiation monitoring that is required to minimise the necessity for human interaction and consequently prevent possible exposure

PELAN (the initials of Pulsed Elemental Analysis with Neutrons) is a device that has been developed to identify a landmine through the elemental constituents of its explosive. PELAN uses neutrons as the probing particles. The incident neutrons interact with the nuclei of the various chemical elements in the mine, emitting characteristic gamma rays that act as the fingerprints of the various chemical elements. PELAN is capable of identifying with the same probability of detection all types of high explosives (TNT, RDX etc.) either in plastic or metal encased landmines. Results of its evaluation with blind tests in Croatia and the US using anti-personnel and anti-tank landmines will be presented.

A radiation detector capable of providing both spectroscopic and directional information would allow users to more rapidly identify and localize radioactive sources, ultimately reducing the time spent in a radiation field. The directional gamma-ray probe (DGRP) described here is a unique, single-hand operated, portable, lightweight gamma detector for use in a high gamma-ray field. It contains two sensors, one providing directional information and the other for spectroscopy, which are housed in a plastic molded enclosure designed to meet weather resistant requirements and decontamination considerations. This paper will describe design features, software development and detector response of this novel radiation detector

In this work results of ongoing research are presented for the LYSO/LuYAP phoswich solution adapted in the ClearPETtrade scanner with depth-of-interaction capability. The use of artificial neural network has been found as a very efficient phoswich crystal layer identification method that works for scintillators used at present, as well as on prospective materials. The LYSO/LuAP and LYSO/GSO phoswiches have been identified as a promising candidates for future PET scanners

A spectroscopic radiation portal monitor (SPM) prototype consisting of four 10.16-cmtimes10.16-cmtimes40.64-cm sodium iodide (NaI) crystals has been constructed at Pacific Northwest National Laboratory (PNNL). The prototype was put through a variety of tests, including measurements of the absolute detection efficiency of unshielded sources and the detection efficiency and isotopic identification capability of the detector for shielded isotopic sources. The monitor's response to various types of cargo and source configurations was also studied. The results of these tests are presented in this report

This work describes a study of artificial neural network on explosive detection. With PFTNA method, gamma-ray spectra of some explosives and common materials were acquired. A multilayer perception neural network was designed and trained with these spectra. Back-propagation algorithm was used as the training method. For faster training, different improved algorithms were tested. Good results have been obtained with some algorithms.

The Suzaku Wide‐band All‐sky Monitor (WAM), realized by large thick anti‐coincidence shields of the Hard X‐ray Detector (HXD), can be powerful gamma‐ray burst (GRB) detector which is sensitive to 50–5000 keV gamma‐rays. The WAM is now in a full operational phase, and we have already detected some GRBs simultaneously with other satellites (Swift, Konus‐Wind, HETE2 and INTEGRAL SPI/ACS). The most impressive event among detected GRBs is GRB051008, which was detected up to 2 MeV with the WAM. In this paper, we report on the WAM in‐flight performance as a GRB monitor from initial three‐months operations, focusing on the GRB trigger status and spectral analysis of GRB051008 and GRB051111 combined with Swift.

The observational properties of the short‐duration gamma‐ray bursts are reviewed. The time histories and energy spectra of these bursts, whether they are observed by the interplanetary network, HETE, Swift, or BATSE, appear to be drawn from the same sample. However, the fluences of the bursts differ considerably; in order of decreasing fluence, they are the bursts observed by the IPN, HETE, Swift, and BATSE. This suggests that, just as for the long duration bursts, Swift may be observing a more distant population. The question of whether some events could be extragalactic giant magnetar flares is examined. One recent event, GRB051103, may be in this category.

It has been demonstrated that the colors of optical afterglows (OAs) of GRBs are unique and almost identical for most of these events detected and analyzed in detail so far. This enables conclusions toward physics of the source and physics of the source environment. In addition, OAs can be identified on CCD images taken at one time but in various filters. In this study, we compare the color behaviour of OAs of GRBs with those of other extragalactic objects. We will show that not only the physical processes involved as well as environment of the objects can be studied this way but also a classification of objects of various types is possible with color photometric data provided e.g. by deep CCD searches and experiments.

We refer on the recent developments of LOBSTER project suggesting novel wide‐field Lobster‐Eye type of X‐ray All Sky Monitor to detect and to analyze GRBs including XRF and X‐ray rich GRBs. The triggers can be detected and localized by their X‐ray emission in the 0.1 – 8 keV energy range. The system exhibits fine detecting sensitivities of order of 10–12 ergcm−2s−1 and the localization accuracy is of order of a few arcmin. The LOBSTER is expected to contribute significantly to analyses of GRBs and especially the XRFs.

We present a simulation study of the effect of different degrees of collimation on countrate performance of a hypothetical PET scanner with LSO crystals. The simulated scanner is loosely based on the geometry of the Siemens Biograph Hi-Rez scanner. System behavior is studied with a photon tracking simulation package (SimSET). We investigate the NEMA NU2-2001 count rate and scatter fraction behavior for systems with different amounts of collimation, which is acheived by adding septa to the fully-3d system as in clinical use. We study systems with 2,5,11, and 40 septa. The effect of collimation is studied for three patient thicknesses. The resulting count rate curves for true, scattered, and random coincidences as well as noise equivalent count rates are compared for the different collimation cases. Improved countrate performance with partial collimation is seen. However, except for the largest diameter phantom, the NEC rate increase is seen at higher activities than those used clinically. The NEC countrate versus activity curves for the LSO systems are also compared to those from a BGO system where partial collimation increases NEC countrate over a clinically relevant activity range.

An investigation of high-pressure xenon (HPXe) detector energy resolution is reported in this submission. A coplanar-anode HPXe chamber has been successfully developed, but the energy resolution is not as good as expected. A simulation package is used to investigate the contributions of various physical processes to the measured photopeak broadening. Hardware improvements and the use of position-sensing techniques are proposed to improve the detector performance.

Recently, diode-like In/CdTe/Pt detectors have been realized which look very promising thanks to their enhanced spectroscopic performance. Scope of this work is to investigate the electric field distribution inside these detectors and its temporal evolution by means of the Pockels effect. The implemented set-up allows us to map the electric field and thus to extract the field profiles between the contacts. The analysis shows that the field is mainly confined below the anode. After applying the bias, these detectors are not very stable at room temperature, and they present a pronounced degradation in spectroscopic performance. This degradation is correlated in this work to the evolution of the electric field which has been observed to dasiamovepsila towards the anode. We attribute this dasiapolarizationpsila behavior in CdTe detectors to the concomitance of two factors: the presence of deep levels in the bulk material, and the high hole barrier height of In on CdTe.

The majority of practical radioactive materials decay by modes that include γ‐ray emission. For questions of “how much” or “how pure,” one must know the absolute intensities of the major radiations. We are using liquid scintillation counting (LSC) to measurements of disintegration rates, coupled with γ‐ray spectroscopy to measure absolute γ‐ray emission probabilities. Described is a study of the 227Th chain yielding absolute γ‐ray intensities with ∼0.5% accuracy and information on LSC efficiencies.

Special nuclear material (SNM) hidden in sea-going cargo containers has been identified as a significant threat at US ports, consequently several SNM detection schemes based on imaging and active interrogation techniques are being developed. Since it has proven difficult to establish what standard cargos should be, we analyzed shipping manifests for US imports shipped through North American ports collected on 14 days distributed over 12 months, and obtained several distribution functions of interest to the cargo scanning community, such as average densities, commodity categories, and packaging types. The "Nuclear Carwash", a cargo scanning technique currently under development at LLNL is based on neutron active interrogation, and relies on the unique signature of beta-delayed gammas emitted by fission products in the 3 to 7 MeV energy range. 19F(n,alpha)16N, has been identified as the main potential interference for neutrons in the 7 to 9 MeV range and estimates of cargo compositions based on manifests identified as containing fluorine are presented.