Monte Carlo Calculations of Neutron Pentration through Graphite and Polyethylene at Energies of 30 and 45 MeV

A new Monte Carlo code was developed to calculate neutron penetration through graphite and hydrocarbon. The accuracy of the code was checked with the experimental values. Attenuation profiles of 30 and 45 MeV monoenergetic neutrons through graphite and polyethylene slabs were obtained by the Monte Carlo calculation. Macroscopic removal cross sections were calculated from the profiles

Measurements of Total Neutron Cross Sections of C, Fe, Pb, O, Mo, Si, Zn, Ni, Sn, Ti and W at Energies 20-60 MeV

Measurements of total neutron cross sections of C, Fe, Pb, O, Mo, Si, Zn, Ni, Sn, Ti and W were made, using white neutrons from a thick Cu target bombarded by 65- and 75-MeV protons. The cross sections were obtained in the energy range 20-60 MeV. The obtained data agree well with others in the case where other data were already existing. The present work added several new data points for Ni, Mo, Sn, Zn, Ti and W, for which the number of existing data was not enough

Measurement of Neutron Activation Cross Sections in the 7Li(p,n)7Be Monoenergetic Neutron Field for Neutron Energy Range of 15 MeV to 40 MeV

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Measurement of Neutron Spallation Cross Sections of 12C, 27Al and 209Bi

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Activation Cross Section Measurements by 15-35 MeV Quasi-Monoenergetic p-Be Neutrons

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PoGOLite - A High Sensitivity Balloon-Borne Soft Gamma-ray Polarimeter

We describe a new balloon-borne instrument (PoGOLite) capable of detecting 10% polarisation from 200mCrab point-like sources between 25 and 80keV in one 6 hour flight. Polarisation measurements in the soft gamma-ray band are expected to provide a powerful probe into high-energy emission mechanisms as well as the distribution of magnetic fields, radiation fields and interstellar matter. At present, only exploratory polarisation measurements have been carried out in the soft gamma-ray band. Reduction of the large background produced by cosmic-ray particles has been the biggest challenge. PoGOLite uses Compton scattering and photo-absorption in an array of 217 well-type phoswich detector cells made of plastic and BGO scintillators surrounded by a BGO anticoincidence shield and a thick polyethylene neutron shield. The narrow FOV (1.25msr) obtained with well-type phoswich detector technology and the use of thick background shields enhance the detected S/N ratio. Event selections based on recorded phototube waveforms and Compton kinematics reduce the background to that expected for a 40-100mCrab source between 25 and 50keV. A 6 hour observation on the Crab will differentiate between the Polar Cap/Slot Gap, Outer Gap, and Caustic models with greater than 5 sigma; and also cleanly identify the Compton reflection component in the Cygnus X-1 hard state. The first flight is planned for 2010 and long-duration flights from Sweden to Northern Canada are foreseen thereafter.Comment: 11 pages, 11 figures, 2 table

Surface radio-mineralisation mediates chelate-free radiolabelling of iron oxide nanoparticles

We introduce the concept of surface radio-mineralisation (SRM) to describe the chelate-free radiolabelling of iron-oxide and ferrite nanoparticles. We demonstrate the effectiveness of SRM with both 111In and 89Zr for bare, polymer-matrix multicore, and surface-functionalised magnetite/maghemite nanoparticles; and for bare Y3Fe5O12 nanoparticles. By analogy with geological mineralisation (the hydrothermal deposition of metals as minerals in ore bodies or lodes) we demonstrate that the heat-induced and aqueous SRM process deposits radiometal-oxides onto the nanoparticle or core surfaces, passing through the matrix or coating if present, without changing the size, structure, or magnetic properties of the nanoparticle or core. We show in a mouse model followed over 7 days that the SRM is sufficient to allow quantitative, non-invasive, prolonged, whole-body localisation of injected nanoparticles with nuclear imaging