Optically detonated explosive device

A technique and apparatus for optically detonating insensitive high explosives, is disclosed. An explosive device is formed by containing high explosive material in a house having a transparent window. A thin metallic film is provided on the interior surface of the window and maintained in contact with the high explosive. A laser pulse provided by a Q-switched laser is focussed on the window to vaporize the metallic film and thereby create a shock wave which detonates the high explosive. Explosive devices may be concurrently or sequentially detonated by employing a fiber optic bundle to transmit the laser pulse to each of the several individual explosive devices

A High-efficiency, Small, Solid-state Laser for Pyrotechnic Ignition

A completely self-contained, small, neodymium laser has been designed and demonstrated for use in a pyrotechnic ignition system. A nominal 16 J of laser energy (1.06 micron wavelength, 1-ms duration) was achieved in a rectangular 10.5-X 15.1-X 25.4-cm package weighting 5.14 kg. This high energy-to-weight ratio is encouraging for laser applications in which specific energy efficiency (energy per unit weight or volume) is important. The laser design concepts are described, and some results on pyrotechnic ignition are given. Some details on a laser currently under construction, which will be 1/8 the size of the above laser, are included

Griscelli syndrome type 2: long-term follow-up after unrelated donor bone marrow transplantation

Griscelli syndrome (GS) is a rare autosomal recessive disease characterized by silvery hair ('partial albinism'). Three forms exist; GS type 2 (GS2), the most common one, is characterized by severe primary immunodeficiency with acute episodes of hemophagocytic lymphohistiocytosis (HLH) which may be fatal in the absence of hematopoietic stem cell transplantation. A 5-year-old boy with HLH was referred to us because of silvery-gray hair present since birth. Abnormal pigment clumps were observed in the medulla of hair shafts on light microscopy. Electron microscopy of a skin biopsy revealed melanosomes in melanocytes, but not in keratinocytes. Leukocytes were devoid of intracytoplasmic granules on blood smear. Neurological signs were absent. Genotyping revealed a homozygous haplotype for polymorphic markers linked to the RAB27A locus, but no RAB27A mutation. A diagnosis of GS2 was established. The patient received bone marrow transplantation (BMT) from an unrelated donor, and after 72 months he did not show relapse of HLH. The long, uneventful follow-up supports the use of BMT from an unrelated donor if transplantation from a relative is not possible

Low‐cost flexible thin‐film detector for medical dosimetry applications

The purpose of this study is to characterize dosimetric properties of thin film photovoltaic sensors as a platform for development of prototype dose verification equipment in radiotherapy. Towards this goal, flexible thin‐film sensors of dose with embedded data acquisition electronics and wireless data transmission are prototyped and tested in kV and MV photon beams. Fundamental dosimetric properties are determined in view of a specific application to dose verification in multiple planes or curved surfaces inside a phantom. Uniqueness of the new thin‐film sensors consists in their mechanical properties, low‐power operation, and low‐cost. They are thinner and more flexible than dosimetric films. In principle, each thin‐film sensor can be fabricated in any size (mm2 – cm2 areas) and shape. Individual sensors can be put together in an array of sensors spreading over large areas and yet being light. Photovoltaic mode of charge collection (of electrons and holes) does not require external electric field applied to the sensor, and this implies simplicity of data acquisition electronics and low power operation. The prototype device use for testing consists of several thin film dose sensors, each of about 1.5 cm×5 cm area, connected to simple readout electronics. Sensitivity of the sensors is determined per unit area and compared to EPID sensitivity, as well as other standard photodiodes. Each sensor independently measures dose and is based on commercially available flexible thin‐film aSi photodiodes. Readout electronics consists of an ultra low‐power microcontroller, radio frequency transmitter, and a low‐noise amplification circuit implemented on a flexible printed circuit board. Detector output is digitized and transmitted wirelessly to an external host computer where it is integrated and processed. A megavoltage medical linear accelerator (Varian Tx) equipped with kilovoltage online imaging system and a Cobalt source are use to irradiate different thin‐film detector sensors in a Solid Water phantom under various irradiation conditions. Different factors are considered in characterization of the device attributes: energies (80 kVp, 130 kVp, 6 MV, 15 MV), dose rates (different ms × mA, 100–600 MU/min), total doses (0.1 cGy‐500 cGy), depths (0.5 cm–20 cm), irradiation angles with respect to the detector surface (0°‐180°), and IMRT tests (closed MLC, sweeping gap). The detector response to MV radiation is both linear with total dose (~1‐400 cGy) and independent of dose rate (100‐600 Mu/min). The sensitivity per unit area of thin‐film sensors is lower than for aSi flat‐panel detectors, but sufficient to acquire stable and accurate signals during irradiations. The proposed thin‐film photodiode system has properties which make it promising for clinical dosimetry. Due to the mechanical flexibility of each sensor and readout electronics, low‐cost, and wireless data acquisition, it could be considered for quality assurance (e.g., IMRT, mechanical linac QA), as well as real‐time dose monitoring in challenging setup configurations, including large area and 3D detection (multiple planes or curved surfaces). PACS number: 87.56.F

Data acquisition system for a proton imaging apparatus

New developments in the proton-therapy field for cancer treatments, leaded Italian physics researchers to realize a proton imaging apparatus consisting of a silicon microstrip tracker to reconstruct the proton trajectories and a calorimeter to measure their residual energy. For clinical requirements, the detectors used and the data acquisition system should be able to sustain about 1 MHz proton rate. The tracker read-out, using an ASICs developed by the collaboration, acquires the signals detector and sends data in parallel to an FPGA. The YAG:Ce calorimeter generates also the global trigger. The data acquisition system and the results obtained in the calibration phase are presented and discussed

Isotopic Composition of Light Nuclei in Cosmic Rays: Results from AMS-01

The variety of isotopes in cosmic rays allows us to study different aspects of the processes that cosmic rays undergo between the time they are produced and the time of their arrival in the heliosphere. In this paper we present measurements of the isotopic ratios 2H/4He, 3He/4He, 6Li/7Li, 7Be/(9Be+10Be) and 10B/11B in the range 0.2-1.4 GeV of kinetic energy per nucleon. The measurements are based on the data collected by the Alpha Magnetic Spectrometer, AMS-01, during the STS-91 flight in 1998 June.Comment: To appear in ApJ. 12 pages, 11 figures, 6 table

A Study of Cosmic Ray Secondaries Induced by the Mir Space Station Using AMS-01

The Alpha Magnetic Spectrometer (AMS-02) is a high energy particle physics experiment that will study cosmic rays in the $\sim 100 \mathrm{MeV}$ to $1 \mathrm{TeV}$ range and will be installed on the International Space Station (ISS) for at least 3 years. A first version of AMS-02, AMS-01, flew aboard the space shuttle \emph{Discovery} from June 2 to June 12, 1998, and collected $10^8$ cosmic ray triggers. Part of the \emph{Mir} space station was within the AMS-01 field of view during the four day \emph{Mir} docking phase of this flight. We have reconstructed an image of this part of the \emph{Mir} space station using secondary $\pi^-$ and $\mu^-$ emissions from primary cosmic rays interacting with \emph{Mir}. This is the first time this reconstruction was performed in AMS-01, and it is important for understanding potential backgrounds during the 3 year AMS-02 mission.Comment: To be submitted to NIM B Added material requested by referee. Minor stylistic and grammer change

Search for the standard model Higgs boson in the H to ZZ to 2l 2nu channel in pp collisions at sqrt(s) = 7 TeV

A search for the standard model Higgs boson in the H to ZZ to 2l 2nu decay channel, where l = e or mu, in pp collisions at a center-of-mass energy of 7 TeV is presented. The data were collected at the LHC, with the CMS detector, and correspond to an integrated luminosity of 4.6 inverse femtobarns. No significant excess is observed above the background expectation, and upper limits are set on the Higgs boson production cross section. The presence of the standard model Higgs boson with a mass in the 270-440 GeV range is excluded at 95% confidence level.Comment: Submitted to JHE