Tertiary particle production and target optimization of the H2 beam line in the SPS North Area

In this note, the tertiary particle yield from secondary targets of different materials placed at the 'filter' position of the H2 beam line of SPS North Area are presented. The production is studied for secondary beams of different momenta in the range of 50-250 GeV/c. More specifically, we studied six different targets: two copper cylinders with a radius of 40 mm and lengths of 100 and 300 mm, one solid tungsten cylinder with a radius of 40 mm and a length of 150 mm and three polyethylene cylinders with radius of 40 mm and lengths of 550, 700 and 1000 mm. Eight different momenta of the secondary beam (50, 60, 70, 100, 120, 150, 200 and 250 GeV/c) as well as two different physics lists (QGSP_BIC and FTFP_BERT) have been extensively studied. The purpose of this study is (a) to optimize (using the appropriate filter target) the particle production from the secondary targets as demanded by the experiments (b) investigate the proton production (with respect to the pion production) in the produced tertiary beams, a fact interesting for cross-section measuring experiments (e.g. NA61), (c) provide an expected beam-composition database for each target and energy that will act as a reference for the test-beam users of the North Area and (d) demonstrate the differences between the different GEANT-4 physics lists. Moreover this work constitutes a starting point for a more detailed benchmark of the different available Monte-Carlo models and codes in this momentum range

Design Optimisation of a High Intensity Beam Facility and Feasibility Experiment of a Solid Fragmented Target

The present PhD thesis describes the design, execution and results of the HRMT-10 experiment performed at the HiRadMat facility of the CERN/SPS complex. The first part of the thesis covers the design optimization studies of the HiRadMat facility, focusing in particular on the radiation protection issues. A detailed Monte-Carlo model of the facility has been developed and validated through comparison with measurements. A very satisfactory agreement between the simulation and the experimental data is observed. In the second part of this thesis, a novel feasibility experiment of a fragmented solid target for a future Neutrino Factory or a Super Beam facility, able to support high beam powers ( 1 MW) is presented in detail. A solid granular target has been proposed as an interesting alternative to an open Hg jet target, presently considered as the baseline for such facilities, but posing considerable technical challenges. The HRMT-10 experiment seeks to address the lack of experimental data of the feasibility of a tungsten powder as such a target. The instrumentation of the experiment was based on remote high-speed photography as well as on Laser-Doppler vibration measurements of the target containers (through a mirror setup and behind a specially designed shielding). The behavior of the powder as a function of the beam parameters is analyzed, and the different disruptive effects observed due to the beam impact are described. For the first time, the proton induced velocities of powder filaments were measured. Values of up to 1.5 m/s for a proton bunch intensity of 2.94 10^{11} at 440 GeV were observed. A theoretical model of the behavior of the target after the impact of the beam has been developed, and is found to be in good agreement with the experimental data. The extrapolation from the measured disruption speeds to the nominal beam parameters of a Neutrino Factory show a projected maximum speed of 30 m/s for the powder grains. This speed appears to pose no practical problems for any foreseeable type of container, and therefore tungsten powder can be considered as a valid option for a future high-power beam facility able to support 1 MW of beam power

Beam performance and instrumentation studies for the ProtoDUNE-DP experiment of CENF

In this note, we address the beam performance (particle content, rates) with emphasis on the momentum determination and particle identification methods for the new H2-VLE (Very Low Energy) beam line that will serve the double phase ProtoDUNE experiment (also known as WA105), in the framework of the CENF project. The proposed instrumentation is configured to achieve an optimal pi/K/proton separation over the full spectrum of provided beam energies, from 0.4 GeV up to 12 GeV, as well as precise momentum measurement to a percent level, if required by the experiment. This note focuses on the H2-VLE beam line for the Double Phase ProtoDUNE experiment, however the same approach can be implemented for the H4-VLE beam, since the design of the two beam lines is very similar

Radiological assessment of the Collimator Materials tests at HiRadMat in 2012

A test for several collimator materials is planned to be performed in the HiRadMat facility of CERN/SPS. Before these samples can be brought to a surface laboratory for analysis after the irradiation, a certain cool-down period has to be respected in order to avoid unjustified exposure of personnel to residual radiation. In the present document, the results of Monte Carlo simulations performed for the radiological assessment of this experiment, are being presented

Test run for the HRMT-15 (RPINST) experiment

The present document discusses the results of the measurements carried out during the test run performed before the main beam time of the HRMT-15 (RPINST) experiment in the HiRadMat facility, which is planned for October 2012. A prototype detector, specifically designed for measuring pulsed neutron fields, was employed in different positions in order to evaluate the stray neutron field conditions in the TA7 tunnel of HiRadMat. Critical points to be taken into account for the main experiment in October are presented, along with solutions to overcome them

Experimental proposal Test of radiation protection instrumentation in HiRadMat

The knowledge of the response of radiation protection detectors in pulsed fields is very important, since this is a typical condition often encountered with stray radiation fields around particle accelerators at CERN and elsewhere. This document presents a proposal for testing a prototype detector and commercial instrumentation in use with the RAMSES monitoring system, due to the unique conditions that can be found in the HiRadMat facility. These tests can be extended to include instrumentation in use at other laboratories, both commercial devices and prototype units, and become an intercomparison benchmark exercise. Additional measurements include Bonner Sphere Spectrometry (BSS) measurements to verify experimentally the neutron spectra and ambient dose equivalent rates simulated by FLUKA inside HiRadMat

Prompt, Activation and Background radiation studies for the HiRadMat facility of CERN/SPS

HiRadMat (High Irradiation to Materials) is a new facility under construction at CERN designed to provide high intensity beams in order to test raw materials and accelerator components with respect to the effect caused by the impact of pulsed, high intensity particle beams. In the present note detailed Monte-Carlo simulations studies using the FLUKA code have been performed for prompt dose equivalent rates in the corresponding tunnel structure as well as surface buildings, residual dose rates (after seven cooling times) for an exemplary irradiation of an LHC collimator, as well as for the remnant background dose in the tunnels after one year of operating the facility. Moreover, calculations of the possible activation of the cooling water in the dump have been performed. The scope of this document includes the operational aspects of the facility but does not cover experiment specific hazards or waste issues as they need to be studied on an individual basis

Feasibility Experiment Of Granular Target Options for Future Neutrino Facilities

Fragmented solid targets made of either fluidised tungsten powder or static pebble bed of tungsten spheres, have been long proposed and are being studied as an alternative configuration towards high-power (>1 MW of beam power) target systems, suitable for a future Super Beam or Neutrino Factory. Such assemblies offer many advantages as better thermal and inertial stress absorption, thermal cooling and, if in the fluidised form, regeneration. We propose to perform a validation test of a tungsten powder target. The proposed feasibility experiment will try on a pulse-by-pulse basis to address the effect of the impact of a high-power pulsed beam in such an assembly using both online diagnostic tools with high-speed cameras, laser vibrometry and acoustic measurements, as well as offline, post-irradiation analysis of the target material