Neutron Imager and Flux Monitor Based on Micro Channel Plates (MCP) in Electrostatic Mirror Configuration

AbstractIn this paper, a new high transparency device based on MCP for the monitoring the flux and spatial profile of a neutron beam will be described. The assembly consists of a carbon foil with a 6Li deposit, placed in the beam, and a MCP equipped with a phosphor screen readout viewed by a CCD camera, placed outside the beam. Secondary emitted electrons (SEE) produced in the carbon foil by the alpha-particles and tritons from the 6Li+n reaction, are deflected to the MCP detector by means of an electrostatic mirror, suitably designed to preserve the spatial resolution. The conductive layer on the phosphor can be used for neutron counting, and to obtain time-of-flight information.A peculiar feature of this device is that the use of an electrostatic mirror minimizes the perturbation of the neutron beam, i.e. absorption and scattering. It can be used at existing time-of-flight (TOF) facilities, in particular at the n_TOF facility at CERN, for monitoring the flux and special profile of the neutron beam in the thermal and epithermal region.In this work, the device principle and design will be presented, together with the main features in terms of resolution and neutron detection efficiency

Neutron imager with micro channel plates (MCP) in electrostatic mirror configuration: Experimental test with radiation source

The design of a new high-transparency device based on a Micro Channel Plate (MCP) detector was recently proposed for monitoring the flux and beam spatial profile of neutron beams. The proposed device consists of a very thin aluminum (Al) foil (with a [Formula: see text]Li deposit) placed in the neutron beam and an MCP detector equipped with a phosphor-screen readout linked to a charge-coupled device (CCD) camera outside the neutron beam. A critical feature of this device is that it uses an electrostatic mirror to minimize the perturbation of the neutron beam (i.e., absorption and scattering). It can be used at existing neutron time-of-flight (n_TOF) facilities (in particular at the n_TOF facility at CERN) for monitoring the flux and spatial profile of neutron beams in the thermal and epithermal region. The experimental tests conducted for this study using a radioactive source to determine the behavior of the electrostatic mirror behavior will be presented and discussed in this paper

Neutron Imager with Micro Channel Plates (MCP) in Electrostatic Mirror Configuration: First Experimental Test

Abstract The idea of a new high transparency device based on Micro Channel Plates (MCP) has been recently presented for monitoring the flux and spatial profile of neutron beams. It consists of the assembly of a very thin aluminum foil with a 6Li deposit placed in the beam and a MCP equipped with a phosphor screen readout viewed by a CCD camera. A peculiar feature of this device is that it uses a 90° electrostatic mirror to minimize the perturbation of the neutron beam, i.e. absorption and scattering. It can be used at existing time-of-flight facilities, in particular at the n_TOF facility at CERN, for monitoring the flux and spatial profile of neutron beams in the thermal and epithermal region. In this contribution the first experimental test carried out by using radioactive sources will be presented and the related results discussed

new beam scanning device for active beam delivery system bds in proton therapy

Abstract A new Beam Delivery System (BDS) has been studied in the framework of a new proton therapy project, called AMIDERHA. It is characterized by an active scanning system for target irradiation with a pencil beam. The project is based on the use of a Linac with variable final energy and the Robotized Patient Positioning System instead of the traditional gantry. As a consequence, in the active BDS of AMIDERHA a pencil beam scanning system with a relatively long Source to Axis Distance (SAD) can be used. In this contribution, the idea of using a unique new device capable of both horizontal and vertical beam scansion for the AMIDERHA active BDS will be presented and discussed. Furthermore, a preliminary design of that device will be shown, together with the results of simulations

Fast Damping in Beam Envelope Oscillation Amplitudes of mismatched high intensity beams

Abstract Recently, a very fast damping of beam envelope oscillation amplitudes has been observed in simulations of high intensity beams transportation through periodic FODO cells, in mismatched conditions In this presentation, further simulations, which seem confirm that the fast damping is due to the Landau damping effect, will be shown and discussed with more details

On the optimal energy of epithermal neutron beams for BNCT

The optimal neutron energy for the treatment of deep-seated tumours using boron neutron capture therapy is studied by analysing various figures of merit. In particular, analysis of the therapeutic gain as a function of the neutron energy indicates that, with the currently available 10 B carriers, the most useful neutrons for the treatment of deep-seated tumours, in particular glioblastoma multiforme, are those with an energy of a few keV. Based on the results of the simulations, a method is presented which allows us to evaluate the quality of epithermal neutron beams of known energy spectrum, thus allowing us to compare different neutron-producing reactions and beam-shaping assembly configurations used for accelerator-based neutron sources

An EBIS for charge state breeding in the SPES project

The 'charge state breeder', BRIC (breeding ion charge) is in construction at the INFN section of Bari (Italy). It is based on EBIS scheme and it is designed to accept radioactive ion beam (RIB) with charge state +1 in a slow injection mode. This experiment can be considered as a first step towards the design and construction of a charge breeder for the SPES project. The new feature of BRIC, with respect to the classical EBIS, is given by the insertion, in the ion chamber, of a rf-quadrupole aiming at filtering the unwanted masses and then making a more efficient containment of the wanted ions. In this paper, the breeder design, the simulation results of the electron and ion beam propagation and the construction problems of the device will be reported

Present Status and Future Programs of the n_TOF Experiment

This is an Open Access article distributed under the terms of the Creative Commons Attribution-Noncommercial License 3.0, which permits unrestricted use, distribution, and reproduction in any noncommercial medium, provided the original work is properly citedThe neutron time-of-flight facility n_TOF at CERN, Switzerland, operational since 2001, delivers neutrons using the Proton Synchrotron (PS) 20 GeV/c proton beam impinging on a lead spallation target. The facility combines a very high instantaneous neutron flux, an excellent time of flight resolution due to the distance between the experimental area and the production target (185 meters), a low intrinsic background and a wide range of neutron energies, from thermal to GeV neutrons. These characteristics provide a unique possibility to perform neutron-induced capture and fission cross-section measurements for applications in nuclear astrophysics and in nuclear reactor technology.The most relevant measurements performed up to now and foreseen for the future will be presented in this contribution. The overall efficiency of the experimental program and the range of possible measurements achievable with the construction of a second experimental area (EAR-2), vertically located 20 m on top of the n_TOF spallation target, might offer a substantial improvement in measurement sensitivities. A feasibility study of the possible realisation of the installation extension will be also presented