Gases with relatively high refractive index, n-1≥500×10-6 at atmospheric pressure, giving a satisfactory photoelectron yield at relatively low pressures (≤5bar) are rare. These gases are often the ...only practical solution for low momentum particle identification in conventional secondary beam lines. The refractive index of R134a, one of the most common gases available to the physics community, has never been measured or reported. In the present note, the results of a dedicated experiment to estimate the refractive index of R134a, using mixed hadron/electron beams in the range 0.5–10GeV are presented.
The present contribution reviews the principle of RF separation and explains its dependence on different parameters of beam optics and hardware. The first examination of potential showstoppers for ...the RF-separated beam implementation for Phase-2 of the AMBER experiment in the M2 beam line of the North Area is presented. Different beam optics settings have been examined, providing either focused or parallel beams inside the RF cavities. The separation and transmission capability of the different optics settings for realistic characteristics of RF cavities are discussed and the preliminary results of the potential purity and intensity of the RF-separated beam are presented. These show that a trade-off between the overall beam intensity and the share of the required particle type in the overall beam needs to be established. No showstoppers have been identified for achieving the beam parameters required for AMBER’s kaonic Primakoff reactions, kaon spectroscopy, prompt-photon production and kaon charge-radius programs. However, the high beam intensity requirements of the AMBER Drell–Yan programme cannot be satisfied with an RF-separated beam.
Abstract
The AMBER-experiment 2, 1, located in the North Experimental Area at CERN, is the successor of the NA58/COMPASS 11 experiment which ran from 2002-2022. AMBER will start its data taking in ...2023. The experiment is served by the M2 beamline, employing secondary and tertiary beams produced by 400 GeV
c
-1
protons from the CERN Super Proton Synchrotron (SPS) impacting the T6 target. For the second phase of their measurements, AMBER will require high-intensity kaon beams 6, 7. This requirement for high-intensity beams implies a need for accurate particle identification allowing tagging particles of interest that would otherwise be lost for analysis. The beam particle identification is carried out using Cherenkov (CEDAR) detectors 5, whose tagging efficiency depends critically on the beam divergence. In this paper we investigate the beam parameters required, the performance achievable with the current layout of the beamline, as well as possible improvements.
An exploratory study has been launched at CERN in 2016 aiming at exploiting the full scientific potential of CERN’s accelerator complex and its scientific infrastructure through projects ...complementary to the LHC, HL-LHC and other possible future colliders. These projects will address possible experiments over the period from 2021 to about 2040. The role of the Conventional Beams Working Group (CBWG) is to study the technical feasibility of a multitude of proposals, particularly in the North Area of CERN. It is also to iterate the beam line performance together with the targeted physics reach and finally to estimate the resources required for changes to the beam lines and experimental areas. The studies assigned to the CBWG and their conclusions are detailed in this article.
The CERN East Area Renovation Montbarbon, E.; Bernhard, J.; Brethoux, D. ...
Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms,
12/2019, Volume:
461
Journal Article
Peer reviewed
The East Area at CERN’s Proton Synchrotron delivers since over 56 years primary proton and ion beams as well as mixed secondary beams of hadrons, electrons and muons in a range of 0.5 GeV/c to ...12 GeV/c. The CERN Management approved in 2016 a full renovation of this intensively used facility. It includes a new flexible beam design to meet todays physics requirements, which concern R&D detector tests, samples analyses under high flux irradiation or physics studies (like the CLOUD experiment). This will result in the ability to run with highly pure electron, hadron or muon beams. The upgrade of the East Area also improves energy consumption with a pulsed powering scheme with new laminated magnets and energy recovering power converters that will reduce both power and cooling requirements. The renovation has already started. The first beam in the new East Area is expected to be delivered in 2021.
The beamlines at CERN's North and East Areas offer secondary beams in a wide range of momenta between 0.5 GeV/c and 400 GeV/c for fixed-target experiments as well as for test beam campaigns with a ...flexible configuration and variable beam composition and intensities. Recently, two new facilities for neutrino detectors tests have been established in an extension of the CERN North Area in context of the CERN Neutrino Platform project. These new tertiary beams extend the current capabilities of the H2 and H4 beamlines towards lower momenta in the range of 0.3 GeV/c to 12 GeV/c, respectively 7 GeV/c, and currently serve the two ProtoDUNE prototype detectors. In addition, a complete overhaul of the CERN East Area is underway, which will provide secondary beams with momenta of up to 15 GeV/c (T9 beam) and 12 GeV/c (T10 beam). New beam optics and an optimised design will allow for electron, hadron and muon beams with high purity. We discuss the layout and performance of both North and East Area beamlines as well as the available infrastructure for the neutrino detector community.
The K12 beamline for the KLEVER experiment van Dijk, M W U; Banerjee, D; Bernhard, J ...
Journal of physics. Conference series,
11/2019, Volume:
1350, Issue:
1
Journal Article
Peer reviewed
Open access
The KLEVER experiment is proposed to run in the CERN ECN3 underground cavern from 2026 onward. The goal of the experiment is to measure BR(KL→π0vv¯), which could yield information about potential new ...physics, by itself and in combination with the measurement of BR(K+→π+vv¯) of NA62. A full description will be given of the considerations in designing the new K12 beamline for KLEVER, as obtained from a purpose made simulation with FLUKA. The high intensities required by KLEVER, 2 × 1013 protons on target every 16.8 s, with 5 × 1019 protons accumulated over 5 years, place stringent demands on adequate muon sweeping to minimize backgrounds in the detector. The target and primary dump need to be able to survive these demanding conditions, while respecting strict radiation protection criteria. A series of design choices will be shown to lead to a neutral beamline sufficiently capable of suppressing relevant backgrounds, such as photons generated by π0 decays in the target, and Λ → nπ0 decays, which mimic the signal decay.
Physics Beyond Colliders is an exploratory study aimed at exploiting the full scientific potential of CERN's accelerator complex up to 2040 and its scientific infrastructure through projects ...complementary to the existing and possible future colliders. Within the Conventional Beam Working Group (CBWG), several projects for the M2 beam line in the CERN North Area were proposed, such as a successor for the COMPASS experiment, a muon programme for NA64 dark sector physics, and the MuonE proposal aiming at investigating the hadronic contribution to the vacuum polarisation. We present integration and beam optics studies for 100 - 160 GeV/c muon beams as well as an outlook for improvements on hadron beams, which include RFseparated options and low-energy antiproton beams and radiation studies for high intensity beams. In addition, necessary beam instrumentation upgrades for beam particle identification and momentum measurements are discussed.
In the framework of the CERN Neutrino Platform project, extensions to the existing SPS North Area secondary beam lines "H2" and "H4", able to provide low-energy charged particles in the momentum ...range from 0.4 to 12 GeV/c, have been designed. The parameters of these "very low energy" beam lines, the expected beam composition as seen by the experiments as well as an outlook on their expected performance are summarized in this paper. Results from Monte-Carlo simulations, important for the optimization of the future instrumentation of the beam lines (serving both the purpose of beam tuning and the experiments' needs for particle identification and momentum measurements), are also presented.
A new kind of positron sources for future linear colliders, where the converter is an aligned tungsten crystal, oriented on the 〈111〉-axis, has been studied at CERN in the WA103 experiment with ...tertiary electron beams from the SPS. In such sources the photons resulting from channeling radiation and coherent bremsstrahlung create the e+e− pairs.
Electron beams, of 6 and 10GeV, were impinging on different kinds of targets: a 4mm thick crystal, a 8mm thick crystal and a compound target made of 4mm crystal followed by 4mm amorphous disk. An amorphous tungsten target 20mm thick was also used for the sake of comparison with the 8mm crystal and to check the ability of the detection system to provide the correct track reconstruction. The charged particles coming out from the target were detected in a drift chamber immersed partially in a magnetic field. The reconstruction of the particle trajectories provided the energy and angular spectrum of the positrons in a rather wide energy range (up to 150MeV) and angular domain (up to 30°). The experimental approach presented in this article provides a full description of this kind of source. A presentation of the measured positron distribution in momentum space (longitudinal versus transverse) is given to allow an easy determination of the available yield for a given momentum acceptance. Results on photons, measured downstream of the positron detector, are also presented. A significant enhancement of photon and positron production is clearly observed. This enhancement, for a 10GeV incident beam, is of 4 for the 4mm thick crystal and larger than 2 for the 8mm thick crystal. Another important result concerns the validation of the simulations for the crystals, for which a quite good agreement was met between the simulations and the experiment, for positrons as well as for photons. These results are presented after a short presentation of the experimental setup and of the track reconstruction procedure.
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