Crystal calorimeters in the next decade

Crystal calorimeter has traditionally played an important role in precision measurement of electrons and photons in high energy physics experiments. Recent interest in calorimeter technology extends its application to measurement of hadrons and jets with dual readout. Potential application of new generation scintillating crystals of high density and high light yield, such as LYSO, in high energy physics experiments is described. Candidate crystals for the homogeneous hadronic calorimeter concept are also discussed

Precision Crystal Calorimeters in High Energy Physics: Past, Present and Future

Precision crystal calorimeters traditionally play an important role in high energy physics experiments. 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 experiments and the progress achieved in understanding crystal's radiation damage as well as in developing high quality scintillating crystals for particle physics. Potential applications of new generation scintillating crystals of high density and high light yield, such as LSO and LYSO, in particle physics experiments is also discussed

The Next Generation of Crystal Detectors

Heavy crystal scintillators are used widely in HEP experiments for precision measurements of photons and electrons. Future HEP experiments, however, require crystal scintillators of more bright, more fast, more radiation hard and less cost. This paper discusses several R&D directions for the next generation of crystal detectors for future HEP experiments.Comment: 5 pages, 2 tables, white paper for the 2013 DPF Snowmass Summer Stud

Gamma ray induced radiation damage in PWO and LSO/LYSO crystals

This paper compares γ-ray induced radiation damage effect in two kinds of heavy crystal scintillators: PWO and LSO/LYSO. Scintillation emission, optical transmission, light output, decay kinetics and light response uniformity were measured for PWO and LSO/LYSO crystal samples of large size before and after γ-ray irradiations. γ-ray induced phosphorescence was also measured, and the corresponding readout noise was determined

Effects of Neutron Irradiations in Various Crystal Samples of Large Size for Future Crystal Calorimeter

In this paper, we report an investigation on the radiation damage effects induced by neutrons in large size crystal scintillator: BGO, CeF_3, LYSO:Ce and PWO. The irradiations were carried out by using fast neutrons from one ^(241)Am-Be and two ^(252)Cf sources. The optical and scintillation properties of these samples, including UV excitation and emission spectra, longitudinal transmission, light output, decay kinetics and light response uniformity, were measured before and after the irradiations. The neutron induced photo-current was also measured, and was used to estimate the readout noise under the neutron flux expected by an electromagnetic calorimeter at a very severe radiation environment. Because of its high light output and excellent radiation resistance LYSO:Ce crystal is found to have the smallest neutron induced readout noise as compared to other large size crystals, indicating it is a good candidate material for a future crystal calorimeter in a severe radiation environment

Emission Spectra of LSO and LYSO Crystals Excited by UV Light, X-Ray and γ-ray

Because of their high stopping power (X_o = 1.14 cm, R_(Moliere) = 2.07 cm) and fast (~ 40 ns) bright (4 times of BGO) scintillation, cerium doped lutetium oxyorthosilicate (LSO) and cerium doped lutetium-yttrium oxyorthosilicate (LYSO) crystals have attracted a broad interest in the high energy physics community. This paper presents a comparative study on emission spectra measured for large size BGO, lead tungstate (PbWO_4), LSO and LYSO samples excited by UV light (photo-luminescence) with and without internal absorption, X-ray (X-luminescence) and gamma-ray (radio-luminescence). A red shift was observed between the emission spectra with internal absorption as compared to that without. An additional red shift and a significant red component were observed in the radio-luminescence spectra measured for LSO samples but not LYSO samples, which were disappeared after a gamma-ray irradiation with an accumulated dose of 5 x 10^3 rad. This is the only significant difference observed between the large size LSO and LYSO samples. The origin of these red shifts and the consequence to their light output and applications in the high energy and nuclear physics experiments are discussed

The Next Generation of Crystal Detectors

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 Study on Correlations Between the Initial Optical and Scintillation Properties and Their Radiation Damage for Lead Tungstate Crystals

This paper presents a study of correlations between the initial optical and scintillation properties and their radiation damage for mass produced lead tungstate crystals. A correlation was observed between crystal's initial light outputs and the values of its initial longitudinal transmittance at 360 nm. A strong correlation was found between the emission weighted radiation induced absorption coefficients and the relative losses of the longitudinal transmittance at 440 nm. Correlations were also observed between the relative losses of crystal's light output and the relative losses of its longitudinal transmittance at 440 nm, or the emission weighted radiation induced absorption coefficients. No correlations were observed between crystal's radiation hardness and its initial longitudinal transmittance or the slope of the initial longitudinal transmittance across the band edge

Crystal gamma-ray detectors for high-energy physics

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

Very fast inorganic crystal scintillators

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 BaF_2 crystals for the proposed Mu2e-II experiment. Applications for Gigahertz hard X-ray imaging will also be discussed