Estimation of Decay Losses and Dynamic Vacuum for the Beta-beam Accelerator Chain

The beta-beam is based on the acceleration and storage of radioactive ions. Due to the large number of ions required and their relatively short lifetime, beam losses are a major concern. This paper estimates the decay losses for the part of the accelerator chain comprising the CERN PS and SPS machines. For illustration purposes, the power deposition in these accelerators is compared to that expected for nominal CNGS proton operation. The beam losses induced vacuum dynamics is simulated and the consequences for machine operation are discussed

The radiation field in the Gamma Irradiation Facility GIF++ at CERN

The high-luminosity LHC (HL-LHC) upgrade is setting now a new challenge for particle detector technologies. The increase in luminosity will produce a particle background in the gas-based muon detectors that is ten times higher than under conditions at the LHC. The detailed knowledge of the detector performance in the presence of such a high background is crucial for an optimized design and efficient operation after the HL-LHC upgrade. A precise understanding of possible aging effects of detector materials and gases is of extreme importance. To cope with these challenging requirements, a new Gamma Irradiation Facility (GIF++) was designed and built at the CERN SPS North Area as successor of the Gamma Irradiation Facility (GIF) during the Long Shutdown 1 (LS1) period. It features an intense source of 662 keV photons with adjustable intensity, to simulate continuous background over large areas, and, combined with a high energy muon beam, to measure detector performance in the presence of the background. The new GIF++ facility has been operational since spring 2015. In addition to describing the facility and its infrastructure, the goal of this work is to provide an extensive characterization of the GIF++ photon field with different configurations of the absorption filters in both the upstream and downstream irradiation areas. Moreover, the measured results are benchmarked with Geant4 simulations to enhance the knowledge of the radiation field. The absorbed dose in air in the facility may reach up to 2.2 Gy/h directly in front of the irradiator. Of special interest is the low-energy photon component that develops due to the multiple scattering of photons within the irradiator and from the concrete walls of the bunker

Feasibility Experiment of a Granular Target for Future Neutrino Facilities

Granular, solid targets made of fluidized tungsten powder or static pebble bed of tungsten spheres, have been proposed and are being studied as an alternative configurations towards high-power (1MW of beam power) target systems, suitable for a future Super Beam or Neutrino Factory. With the lack of experimental data on this field, a feasibility experiment was performed in HiRadMat facility of CERN/SPS that tried on a pulse-by-pulse basis to address the effect of the impact of the SPS beam (440GeV/c) on a static tungsten granular target. Online instrumentation such as high-speed photography and laser-Doppler vibrometry was employed. Preliminary results show a powder disruption speed of less than 0.6 m/s at 3E11 protons/pulse while the disruption speed appears to be scaling proportionally with the beam intensity

A FEASIBILITY EXPERIMENT OF A W-POWDER TARGET IN THE HIRADMAT FACILITY AT CERN

Granular solid targets made of fluidized tungsten powder or a static pebble bed of tungsten spheres, have been proposed and are being studied as an alternative configuration for high-power (>1MW of beam power) target systems, suitable for a future Super Beam or Neutrino Factory. Due to the lack of experimental data on this field, a feasibility experiment was performed in HiRadMat facility of CERN to address the effect of the impact of the SPS beam (440 GeV/c) on a static tungsten powder target. Online instrumentation such as high-speed photography and laser-Doppler vibrometry was employed. Preliminary results show a powder disruption speed of less than 0.6 m/s at 3 1011 protons/pulse while the disruption speed appears to scale with the beam intensity

First Year of Operations in the HiRadMat facility

HiRadMat (High Irradiation to Materials) is a new facility at CERN constructed in 2011. It is designed to provide a test area where the effect of high intensity pulsed beams on materials or accelerator component assemblies can be studied. The HiRadMat facility is situated in the former West Area Neutrino Facility (WANF) target tunnel and is about 35 m below ground. It takes the fast extracted beam from the long straight section LSS6 of SPS, the same used for the TI2 injection line to LHC. For 2012, the first year of operations of the facility, 9 experiments were scheduled and completed data-taking successfully. The experience gained in operating this unique facility, along with highlights of the experiments and the instrumentation developed for online measurements are reported

Quality control of ATLAS muon chambers

ATLAS is a general-purpose experiment for the future Large Hadron Collider (LHC) at CERN. Its Muon Spectrometer will require ∼ 5500m2 of precision tracking chambers to measure the muon tracks along a spectrometer arm of 5m to 15m length, embedded in a magnetic field of ∼ 0.5T. The precision tracking devices in the Muon System will be high pressure drift tubes (MDTs). Approximately 370,000 MDTs will be assembled into ∼ 1200 drift chambers. The performance of the MDT chambers is very much dependent on the mechanical quality of the chambers. The uniformity and stability of the performance can only be assured providing very high quality control during production. Gas tightness, high-voltage behaviour and dark currents are global parameters which are common to gas detectors. For all chambers, they will be tested immediately after the chamber assembly at every production site. Functional tests, for example radioactive source scans and cosmic-ray runs, will be performed in order to establish detailed performance maps. One major issue of the quality control, the gas tightness, is the topic of this thesis. The gas pressure inside the tubes will be 3 bar, the drift gas will be Ar/CO2 93/7. The high spatial resolution made it necessary to define the maximum allowed leak rate for MDT chambers to 2 ∗ 10−8 bar l s . This is equivalent to a pressure drop of about 1 mbar for MDT chambers within one day at the given working point. Several methods had been considered in the past. This thesis deals with an innovative method. The gas gain and hence the signals are a strong function of the gas density. The test on the gas tightness using the tubes itself as sensitive devices makes it possible to determine the leak rate with a sensitivity better than 10−4 within one day. The principle of this method will be discussed and demonstrated. Also the quality control of single tubes can be realized with it. The method allows easy-to-use series controls with integrated test of other chamber properties

HiRadMat: A high‐energy, pulsed beam, material irradiation facility

HiRadMat is a facility constructed in 2011, designed to provide high-intensity pulsed beams to an irradiation area where different material samples or accelerator components can be tested. The facility, located at the CERN SPS accelerator complex, uses a 440 GeV proton beam with a pulse length up to 7.2 μs and a maximum intensity up to 1E13 protons / pulse. The facility, a unique place for performing state-of-the art beam-to-material experiments, operates under transnational access and welcomes and financially supports, under certain conditions, experimental teams to perform their experiments

The Very Low 1-9 GeV/c Tertiary Beam Extension of the H8 Beam Line of CERN SPS

The H8 beam line on the North Area of CERN SPS is a multi purpose experimental secondary particle beam able to transport particles of various types (hadrons, electrons, muons and ions) in a large momentum range from 10 GeV/c up to the top SPS energy (400 or 450 GeV/c). During the 2003-2004 shutdown the beam line was modified in order to accommodate a new tertiary beam line, able to produce and transport particles in the momentum range of 1 to 9 GeV/c. Such low momentum hadron and electron particle beams are requested by the LHC experiments in order to calibrate various sub-detector systems. The design and rst performance results from this new tertiary beam are described here.The H8 beam line on the North Area of CERN SPS is a multipurpose experimental secondary particle beam able to transport particles of various types (hadrons, electrons, muons and ions) in a large momentum range from 10 GeV/c up to the top SPS energy (400 or 450 GeV/C). During the 2003-2004 shutdown the beam line was modified in order to accommodate a new tertiary beam line, able to produce and transport particles in the momentum range of 1 to 9 GeV/c. Such low momentum hadron and electron particle beams are requested by the LHC experiments in order to calibrate various sub-detector systems. The design and first performance results from this new tertiary beam are described here

Status and Planned Experiments of the Hiradmat Pulsed Beam Material Test Facility at CERN SPS

HiRadMat (High Irradiation to Materials) is a facility at CERN designed to provide high-intensity pulsed beams to an irradiation area where material samples as well as accelerator component assemblies (e.g. vacuum windows, shock tests on high power targets, collimators) can be tested. The beam parameters (SPS 440 GeV protons with a pulse energy of up to 3.4 MJ, or alternatively lead/argon ions at the proton equivalent energy) can be tuned to match the needs of each experiment. It is a test area designed to perform single pulse experiments to evaluate the effect of high-intensity pulsed beams on materials in a dedicated environment, excluding long-time irradiation studies. The facility is designed for a maximum number of 1016 protons per year, in order to limit the activation of the irradiated samples to acceptable levels for human intervention. This paper will demonstrate the possibilities for research using this facility and go through examples of upcoming experiments scheduled in the beam period 2015/2016.HiRadMat (High Irradiation to Materials) is a facility at CERN designed to provide high-intensity pulsed beams to an irradiation area where material samples as well as accelerator component assemblies (e.g. vacuum windows, shock tests on high power targets, collimators) can be tested. The beam parameters (SPS 440 GeV protons with a pulse energy of up to 3.4 MJ, or alternatively lead/argon ions at the proton equivalent energy) can be tuned to match the needs of each experiment. It is a test area designed to perform single pulse experiments to evaluate the effect of high-intensity pulsed beams on materials in a dedicated environment, excluding long-time irradiation studies. The facility is designed for a maximum number of 10¹⁶ protons per year, in order to limit the activation of the irradiated samples to acceptable levels for human intervention. This paper will demonstrate the possibilities for research using this facility and go through examples of upcoming experiments scheduled in the beam period 2015/2016

A Feasibility Experiment of a W-powder Target in the HiRadMat Facility of CERN

Granular solid targets made of fluidized tungsten powder or static pebble bed of tungsten spheres, have been long proposed and are being studied as an alternative configurations towards high-power (>1MW of beam power) target systems, suitable for a future Super Beam or Neutrino Factory. Serving the lack of experimental data on this field, a feasibility experiment was performed in HiRadMat facility of CERN/SPS that tried in a pulse-by-pulse basis to address the effect of the impact of the SPS beam (440GeV/c) on a static tungsten powder target. Online instrumentation such as high-speed photography and Laser - Doppler Vibrometry was employed. Preliminary results show a powder disruption speed of less than 0.5 m/s while the disruption height appears to be scaling proportionally with the beam intensity. Other analysis results will be discussed