A muon collider represents the ideal machine to reach very high center-of-mass energies and luminosities by colliding elementary particles. This is the result of the low level of beamstrahlung and ...synchrotron radiation compared to linear or circular electron-positron colliders. In contrast with other lepton machines, the design of a detector for a multi-TeV muon collider requires detailed knowledge of the interaction region due to the significant backgrounds created by muon beam decays in the collider ring. The physics reach can be properly evaluated only when the detector performance in such an environment is determined. In this work, the backgrounds generated by muon beams of 750 GeV are characterized and the performance of the tracking system and the calorimeter detector is illustrated. Solutions to minimize the effect of the beam-induced backgrounds are discussed and applied to obtain track and jet reconstruction performance. The μ+μ−→Hν →b ν process is fully simulated and reconstructed to demonstrate that physics measurements are possible in this harsh environment. The measurement precision for the Higgs boson coupling to b is evaluated for s=1.5, 3, and 10 TeV and compared to other proposed machines.
Accurate measurements of physical processes in high energy frontier experiments demand exceptional spatial, temporal, and energy precision to discern the physics behind high-energy particle jets. ...Calorimeters, like other detection systems, must be able to meet these increasingly challenging performance requirements. In the prospective TeV-scale Muon Collider, the primary hurdle in designing detectors and devising event reconstruction algorithms is the challenge posed by Beam-Induced Background (BIB). Nevertheless, it is conceivable to mitigate the impact of BIB on the Muon Collider's calorimeter by capitalizing on certain characteristics and ensuring key features such as high granularity, precise timing, longitudinal segmentation, and superior energy resolution. This is what the here described Research and Development is trying to achieve with an innovative semi-homogeneous electromagnetic calorimeter constructed from stackable and interchangeable modules composed of lead fluoride crystals (PbF2). These modules are equipped with surface-mount UV-extended Silicon Photomultipliers (SiPMs) and are collectively referred to as the Crilin calorimeter (CRystal calorImeter with Longitudinal INformation). The challenge lies in making sure this calorimeter can operate effectively within an extremely harsh radiation environment, enduring an annual neutron flux of <inline-formula> <tex-math notation="LaTeX">10^{14}~n_{1\text {MeV}}/\text {cm}^{2} </tex-math></inline-formula> and a total ionizing dose (TID) of 10 kGy. In this article, the radiation tolerance measured in several irradiation campaigns is discussed, and the timing performances during a test beam at CERN-H2 with 120-GeV electrons. Additionally, a description of the latest prototype, Proto-1, is provided together with the results of the latest low-energy beam test at the LNF beam test facility (BTF) with 450 MeV electrons.
In modern experiment, a high granularity is required in order to distinguish signal particles from background and to solve the substructures necessary for jet identification. Time of arrival ...measurements in the calorimeter could play an important role in HL-LHC, since a high number of pile-up collisions is expected, and the timing could be used to assign clusters to the corresponding interaction vertex. In a Muon Collider, the timing could be used to remove signals produced by beam-induced background, asynchronous with respect to the bunch crossing. The calorimeter energy resolution is also fundamental to measure the kinematic properties of jets: a finely segmented calorimeter design should be favored in order to solve the jet substructure. However, this contrasts with the requirement for high timing resolution even for signal events involving low energy deposits, such as in the case of high impulse muons. Our proposed design, the Crilin calorimeter, is a semi-homogeneous calorimeter based on Lead Fluoride (PbF
2
) Crystals readout by surface-mount UV-extended Silicon Photomultipliers (SiPMs). In this paper, the development of a small prototype consisting of 2 layers of 3 × 3 crystals each is reported along with the relative results.
Abstract
The measurement of physics processes at new energy frontier
experiments requires excellent spatial, time, and energy resolutions
to resolve the structure of collimated high-energy jets. In a ...future
Muon Collider, the beam-induced backgrounds (BIB) represent the main
challenge in the design of the detectors and of the event
reconstruction algorithms. The technology and the design of the
calorimeters should be chosen to reduce the effect of the BIB, while
keeping good physics performance. Several requirements can be
inferred: i) high granularity to reduce the overlap of BIB particles
in the same calorimeter cell; ii) excellent timing (of the order of
100 ps) to reduce the out-of-time component of the BIB; iii)
longitudinal segmentation to distinguish the signal showers from the
fake showers produced by the BIB; iv) good energy resolution (less
than 10%/
√E
) to obtain good physics performance, as has
been already demonstrated for conceptual particle flow calorimeters.
Our proposal consists of a semi-homogeneous electromagnetic
calorimeter based on lead fluoride crystals (PbF
2
) read out by
surface-mount UV-extended Silicon Photomultipliers (SiPMs): the
Crilin calorimeter. In this paper, the performance of the Crilin
calorimeter in the Muon Collider framework for hadron jets
reconstruction has been analyzed. We report the characterisation of
individual components together with the development of a small-scale
prototype, consisting of 2 layers of 3 × 3 crystals each.
The muon collider represents one of the most promising solutions for a future machine exploring the high energy frontier, but several challenges due to the 2.2 μsec muon lifetime at rest have to be ...carefully considered. The LEMMA project is investigating the possibility of producing low emittance muon/antimuon pairs from the e+e− annihilation process at threshold energy, resulting in small transverse emittance beams without any additional beam cooling. However most of the measurements available are performed at higher s values. It is therefore necessary to measure muons production in positron annihilation at threshold energy and compare the experimental results with the predictions in this specific energy regime. Apart from being a topic of physical interest by itself, these near to threshold measurements can have a sizeable impact on the estimation of the ultimate luminosity achievable in a muon collider with the LEMMA injection scheme.
Detectors for new energy frontier experiments require excellent spatial, time, and energy resolutions to resolve the structure of collimated high-energy jets. In a future Muon Collider, the ...beam-induced backgrounds represent the main challenge for detector design and event reconstruction. Our proposal – Crilin – consists in a semi-homogeneous Cherenkov electromagnetic calorimeter based on PbF2 crystals with surface-mount UV-extended Silicon Photomultipliers readout.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The investigation of the energy frontier in physics requires novel concepts for future colliders. The idea of a muon collider is very appealing since it would allow to study particle collisions at up ...to tens of TeV energy, while offering a cleaner experimental environment with respect to hadronic colliders. One key element in the muon collider design is the low-emittance muon production. Recently, the Low EMittance Muon Accelerator (LEMMA) collaboration has explored the muon pair production close to its kinematic threshold by annihilating 45 GeV positrons with electrons in a low Z material target. In this configuration, muons are emerging from the target with a naturally low-emittance. In this paper we describe the performance of a system, to study this production mechanism, that consists in several segmented absorbers with alternating active layers composed of fast Cherenkov detectors together with a muon identification technique based on this detector. Passive layers were made of tungsten. We collected data corresponding to muon and electron beams produced at the H2 line in the North Area of the European Organization for Nuclear Research (CERN) in September 2018.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The measurement of physics processes at new energy frontier experiments requires excellent spatial, time, and energy resolutions to resolve the structure of collimated high-energy jets. Calorimeters, ...as other detectors, must face this increasing performance demand. In a future TeV-scale Muon Collider, the beam-induced background (BIB) represents the main challenge in the design of the detectors and of the event reconstruction algorithms and can pose serious limitations to the physics performance. However, it is possible to reduce the BIB impact on the Muon Collider calorimeter by exploiting some of its characteristics and by ensuring high granularity, excellent timing, longitudinal segmentation and good energy resolution. The proposed R&D is an innovative semi-homogeneous electromagnetic calorimeter based on stackable modules of lead fluoride crystals (PbF
2
) readout by surface-mount UV-extended Silicon Photomultipliers (SiPMs): the Crilin calorimeter (CRystal calorImeter with Longitudinal INformation). The calorimeter should operate in a very harsh radiation environment, withstanding yearly a neutron flux of 10
14
n1MeV /cm
2
and a dose of 100 krad.
In this paper, the radiation tolerance measured in several irradiation campaigns and the timing performances evaluated during a test beam at CERN-H2 with 120-GeV electron are discussed. A description of the latest prototype Proto-1, that will be shortly tested, is also provided.
Full text
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
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