Some thoughts on the focusing regime for an Alvarez linac

When designing an Alvarez linac the perennial problem arises as to what is the optimum phase advance and focusing structure. This report discusses this question and makes recommendations based on simple criteria. The general conclusions are valid over a wide range of parameters, but the detailed simulations given in the report can be used to calculate the optima more carefully for a particular beam current and energy range. This study is complementary to the AUSTRON Feasibility Study for a fast-cycling, synchrotron-driven neutron spallation source

A CVD diamond detector for (n,alpha) cross section measurements

Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike LicenceIn astrophysics, the determination of the optical alpha-nucleus potential for low alpha-particle energies, crucial in understanding the origin of the stable isotopes, has turned out to be a challenge. Theory still cannot predict the optical potentials required for the calculation of the astrophysical reaction rates in the Hauser-Feshbach statistical model and there is scant experimental information on reactions with alpha particles at the relevant astrophysical energies. Measurements of (n,alpha) cross-sections offer a good opportunity to study the alpha channel. At the n_TOF experiment at CERN, a prototype detector, based on the chemical vapor deposition (CVD) diamond technology, has been recently developed for (n,alpha) measurements. A reference measurement of the 10B(n,alpha)7Li reaction was performed in 2011 at n_TOF as a feasibility study for this detector type. The results of this measurement and an outline for future experiments are presented here

Diamond pixel detector for beam profile monitoring in COMET experiment at J-PARC

We present the design and initial prototype results of a pixellized proton beam profile monitor for the COMET experiment at J-PARC. The goal of COMET is to look for charged lepton flavor violation by direct muon to electron conversion at a sensitivity of $0^{-19}$. An 8 GeV proton beam pulsed at 100 ns with $10^{10}$ protons/s will be used to create muons through pion production and decay. In the final experiment, the proton flux will be raised to $10^{14}$ protons/sec to increase the sensitivity. These requirements of harsh radiation tolerance and fast readout make diamond a good choice for constructing a beam profile monitor in COMET. We present first results of the characterization of single crystal diamond (scCVD) sourced from a new company, 2a systems Singapore. Our measurements indicate excellent charge collection efficiency and high carrier mobility down to cryogenic temperatures.Comment: Pixel 2014 Workshop proceedings in JINS

A 0.5 MW/10 Hz option of the spallation source AUSTRON

In 1993-94 a feasibility study for AUSTRON, a neutron spallation source, was made on behalf of the Austrian Ministry of Science and Research. At that time, the machine was synchrotron cycling at 25 Hz and delivering an average beam power of 205 kW at 1.6 GeV. An option to double the power by doubling the frequency was foreseen. Now a more ambitious development of the original concept is proposed that aims at 0.5 MW at 1.6 GeV, pulsed at either 50 Hz or 10 Hz. The slow repetition rate is achieved by the addition of a storage ring holding four consecutive (single bunch) pulses from the 50 Hz synchrotron until a fifth pulse is accelerated and transferred to the target with the four stored ones. In this way, an energy per pulse of 50 kJ (one half of the pulse energy of the 5 MW ESS) is obtained, yielding about 3.5*10/sup 16/ thermal neutrons/(s cm/sup 2/). This peak flux matches well a number of innovative instruments and allows unprecedented resolution for some more conventional ones. On August 20, 1998, the Austrian Government has unanimously decided to contribute one third of the total cost of the facility and invites international partners to participate. (13 refs)

High-Resolution Energy and Intensity Measurements with CVD Diamond at REX-ISOLDE

A novel beam instrumentation device for the HIE-REX (High In-tensity and Energy REX) upgrade has been developed and tested at the On-Line Isotope Mass Separator ISOLDE, located at the European Laboratory for Particle Physics (CERN). This device is based on CVD diamond detector technology and is used for measuring the beam intensity, particle counting and measuring the energy spectrum of the beam. An energy resolution of 0.6% was measured at a carbon ion energy of 22.8 MeV. This corresponds to an energy spread of ± 140 keV

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