Future HEP experiments at the energy and intensity frontiers require fast inorganic crystal scintillators with excellent
radiation hardness to face the challenges of unprecedented event rate and severe radiation environment. This paper
reports recent progress in application of very fast inorganic scintillators in future HEP experiments, such as thin layer of
LYSO crystals for a shashlik sampling calorimeter and a precision TOF detector proposed for the CMS upgrade at the
HL-LHC, undoped CsI crystals for the Mu2e experiment at Fermilab and yttrium doped BaF2 crystals for the proposed
Mu2e-II experiment. Applications for Gigahertz hard X-ray imaging will also be discussed.
Crystal detectors have been used widely in high energy and nuclear physics experiments, medical instruments and homeland security applications. Novel crystal detectors are continuously being discovered and developed in academia and in industry. In high energy and nuclear physics experiments, total absorption electromagnetic calorimeters (ECAL) made of inorganic crystals are known for their superb energy resolution and detection efficiency for photon and electron measurements. A crystal ECAL is thus the choice for those experiments where precision measurements of photons and electrons are crucial for their physics missions. For future HEP experiments at the energy and intensity frontiers, however, the crystal detectors used in the above mentioned ECALs are either not bright and fast enough, or not radiation hard enough. Crystal detectors have also been proposed to build a Homogeneous Hadron Calorimeter (HHCAL) to achieve unprecedented jet mass resolution by duel readout of both Cherenkov and scintillation light, where development of cost-effective crystal detectors is a crucial issue because of the huge crystal volume required. This paper discusses several R&D directions for the next generation of crystal detectors for future HEP experiments.
A multilayer thin-scintillator concept is described for ultrafast imaging. The individual layer thickness is determined by the spatial resolution and light attenuation length, the number of layers is determined by the overall efficiency. By coating the scintillators with a high quantum-efficiency photocathode, single X-ray photon detection can be achieved using fast scintillators with low light yield. The fast, efficient sensors, when combined with MCP and novel nanostructed electron amplification schemes, is a possible way towards GHz hard X-ray cameras for a few frames of images.
Gigahertz (GHz) imaging technology will be needed at high-luminosity X-ray and charged particle sources. It is
plausible to combine fast scintillators with the latest picosecond detectors and GHz electronics for multi-frame hard Xray
imaging and achieve an inter-frame time of less than 10 ns. The time responses and light yield of LYSO, LaBr3, BaF2 and ZnO are measured using an MCP-PMT detector. Zinc Oxide (ZnO) is an attractive material for fast hard X-ray
imaging based on GEANT4 simulations and previous studies, but the measured light yield from the samples is much
lower than expected.
Precision crystal calorimeter traditionally plays an important role in experimental high energy physics. In the last
two decades, it faces a challenge to maintain its precision in a hostile radiation environment. This paper reviews
the performance of crystal calorimeters constructed for high energy physics experiment and the progress achieved
in understanding crystal's radiation damage and in developing high quality scintillating crystals. Future crystal
calorimeters, such as a LSO and LYSO calorimeter and homogeneous hadronic calorimeter, being considered for
experimental particle physics is also discussed.
This report reviews the design characteristics of crystal gamma ray detectors for high energy physics. The unique physics capability of these detectors is the result of their excellent energy resolution, uniform hermetic coverage and fine granularity. To maintain crystal's resolution in situ radiation hardness is a principle requirement. The performance of various heavy crystal scintillators is discussed. A technical approach to solve radiation damage problem by optical bleaching in situ is elaborated.