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 Mu2e experiment at Fermilab searches for the charged-lepton flavor violating (CLFV) conversion of a negative muon into an electron in the field of an aluminum nucleus, with a distinctive ...signature of a monoenergetic electron of energy slightly below the muon rest mass (104.967 MeV). The Mu2e goal is to improve by four orders of magnitude the search sensitivity with respect to the previous experiments. Any observation of a CLFV signal will be a clear indication of new physics. The Mu2e detector is composed of a tracker, an electromagnetic calorimeter, and an external veto for cosmic rays surrounding the solenoid. The calorimeter plays an important role in providing particle identification capabilities, a fast online trigger filter, a seed for track reconstruction while working in vacuum, in the presence of 1-T axial magnetic field and in a harsh radiation environment. The calorimeter requirements are to provide a large acceptance for 100-MeV electrons and reach at these energies: 1) a time resolution better than 0.5 ns; 2) an energy resolution <10%; and 3) a position resolution of 1 cm. The calorimeter design consists of two disks, each one made of 674-undoped cesium iodine crystals read by two large area arrays of UV-extended silicon photomultipliers (SiPMs). We report here the construction and the test of the Module-0 prototype. The Module-0 has been exposed to an electron beam in the energy range around 100 MeV at the Beam Test Facility in Frascati. Preliminary results of timing and energy resolution at normal incidence are shown. A discussion of the technical aspects of the calorimeter engineering is also reported in this paper.
Abstract
Lead fluoride (PbF
2
) crystals represent an excellent and
relatively innovative choice for high resolution electromagnetic
calorimeters with high granularity and fast timing for high
...intensity environments. For this reason two PbF
2
crystals, sized
5× 5 × 40 mm
3
, were irradiated with
60
Co
photons up to ∼ 4 Mrad and with 14 MeV neutrons up to a
10
13
n/cm
2
total fluence. Their loss in transmittance was
evaluated at different steps of the photon and neutron irradiation
campaign, resulting in a total of 30% loss above 350 nm. With
crystals always kept in dark conditions, natural and thermal
annealing, as well as optical bleaching with 400 nm light, were
performed on the irradiated specimens, resulting in a partial
recovery of their original optical characteristics.
Abstract The timing performance of the Timepix4 application-specific integrated circuit (ASIC) bump-bonded to a 100 μ m thick n-on-p silicon sensor is presented. A picosecond pulsed infrared laser ...was used to generate electron-hole pairs in the silicon bulk in a repeatable fashion, controlling the amount, position and time of the stimulated charge signal. The timing resolution for a single pixel has been measured to 107 ps r.m.s. for laser-stimulated signals in the silicon sensor bulk. Considering multi-pixel clusters, the measured timing resolution reached 33 ps r.m.s. exploiting oversampling of the timing information over several pixels.
The Mu2e experiment is constructing a calorimeter consisting of 1348 undoped cesium iodide (CsI) crystals in two disks. Each crystal has a dimension of 34 × 34 × 200 mm3 and is readout by a ...large-area silicon photomultipliers array. A series of technical specifications on mechanical and optical parameters was defined according to the calorimeter physics requirements. Preproduction CsI crystals were procured from three firms: Amcrys, Saint-Gobain, and Shanghai Institute of Ceramics. We report the quality assurance on crystal's scintillation properties and their radiation hardness against ionization dose and neutrons. With a fast decay time of about 30 ns and a light output of more than 100 p.e./MeV measured by a bialkali photomultiplier tube, undoped CsI crystals provide a cost-effective solution for Mu2e.
The PADME experiment at the LNF Beam Test Facility searches for dark photons produced in the annihilation of positrons with the electrons of a fixed target. The strategy is to look for the reaction ...e++e−→γ+A′, where A′ is the dark photon, which cannot be observed directly or via its decay products. The electromagnetic calorimeter plays a key role in the experiment by measuring the energy and position of the final-state γ. The missing four-momentum carried away by the A′ can be evaluated from this information and the particle mass inferred. This paper presents the design, construction, and calibration of the PADME's electromagnetic calorimeter. The results achieved in terms of equalisation, detection efficiency and energy resolution during the first phase of the experiment demonstrate the effectiveness of the various tools used to improve the calorimeter performance with respect to earlier prototypes.
The Mu2e experiment at Fermilab will search for the charged lepton flavor violating neutrino-less conversion of a negative muon into an electron in the field of an aluminum nucleus <xref ...ref-type="bibr" rid="ref1">1 , <xref ref-type="bibr" rid="ref2">2 . The Mu2e detector is comprised of a tracker, an electromagnetic calorimeter, and an external veto for cosmic rays. The calorimeter plays an important role in providing excellent particle identification capabilities, a fast and online trigger filter while aiding the track reconstruction capabilities. The calorimeter requirements are to provide a large acceptance for 100-MeV electrons and reach: 1) a time resolution better than 0.5 ns at 100 MeV; 2) an energy resolution O(10%) at 100 MeV; and 3) a position resolution of about 1 cm. The calorimeter consists of two disks, each one made of 674 pure CsI crystals readout by two large-area <inline-formula> <tex-math notation="LaTeX">2 \times 3 </tex-math></inline-formula> array of UV-extended silicon photomultipliers (Mu2e SiPMs) of <inline-formula> <tex-math notation="LaTeX">6\,\,\times6 </tex-math></inline-formula> mm 2 dimensions. A large-scale prototype has been constructed with 51 preproduction crystals readout by 102 Mu2e SiPMs. It has been tested at the beam test facility in Frascati, demonstrating satisfying results compared to the Mu2e requirements. At the moment of writing, the crystals production phase is halfway through the work, while the SiPM production has been completed. An overview of the characterization tests is also reported, together with a description of the final calorimeter design.
Abstract
The light yield, the time resolution and the efficiency of
different types of scintillating tiles with direct Silicon
Photomultiplier readout and instrumented with a customised front-end
...electronics have been measured at the Beam Test Facility of
Laboratori Nazionali di Frascati and several test stands. The
results obtained on minimum ionising particles with different
detector configurations are presented. A time resolution of the
order of 300 ps, a light yield of more than 230 photo-electrons, and
an efficiency better than 99.8% are obtained with
∼ 225 cm
2
large area tiles. This technology is suitable
for a wide range of applications in high-energy physics, in
particular for large area muon and timing detectors.
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