N3D1  Scintillators for High-Energy Physics

Wednesday, Nov. 4  16:30-18:10  Town and Country

Session Chair:  Stephen Payne, , United States; Dennis Schaart, Delft University of Technology, Netherlands

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(16:30) N3D1-1, Crystal Fibers for futures calorimeters

E. Auffray1, N. Aubry2, K. Blazek3, A. Benaglia1, C. Dujardin4, S. Diehl5, S. Faraj2, H. Gerwig6, A. Heering7, V. Kononets4, K. Lebbou1, P. Lecoq1, M. Lucchini8, T. Medvedeva5, R. Novotny3, S. Ochesanu3, K. Pauwels1, N. Siegrist1, C. Tully8, H.-G. Zeunig5

1PH, European Organization for Nuclear Research, Geneva, Switzerland
2FIBERCRYST S.A.S, Decines Charpieu, France
3CRYTUR, spol. s r.o, Crytur, Czech Republic
4Institut Lumière Matière, Univ. Lyon 1; CNRS, UMR 5620, Villeurbanne, France
52nd Physics Institute, Justus-Liebig-University, Giessen, Germany
6University of Notre Dame, Notre Dame, Indiana, France
7Institute for Scintillation Materials, National Academy of Sciences of Ukraine, Kharkov, Ukraine
8Princeton University, Princeton, New-Jersey, USA
Future high energy physics experiments, such as HL-LHC, CLIC, ILC and FCC, need major improvements in the performances of hadron and jet calorimetry. Because of the challenging conditions in which they will be operated, unprecedented levels of energy and timing resolutions, as well as efficient particle identification are required. We proposed earlier an approach based on heavy inorganic crystal fibers to form a fully homogeneous calorimeter. Designs based on assemblies of small elements of undoped and doped materials can simultaneously obtain excellent energy resolution and perform particle identification with its dual readout and vertexing/tracking capabilities. In the last years, our group achieved to majorly improve the growth of fiber-shaped single crystals. In these studies, garnet materials (LuAG - Lu3Al5O12 - and YAG - Y3Al5O12) grown in various fiber geometries were considered. We present here a review of the R&D performed during the last years. From the material point of view, the radiation hardness of the garnet structure was demonstrated to be radiation hard and could also be further enhanced by addition of appropriate co-dopants in the melt. The optical quality and the propagation of the light through the crystal fibers were improved to obtain a negligible contribution to the constant term of the energy resolution. The intensive R&D program also included test beam campaigns to evaluate the performances of crystal fibers in various configurations. They demonstrated the flexibility of this innovative type of calorimetry. Physics results were obtained in both transverse and projective designs, with modules either with very fine granularity or rather loose sampling fraction. Based on Geant4 simulations, we also studied the best way to find a good compromise between cost and performances by smartly sacrificing the homogeneity of the calorimeters in specific regions.

(16:50) N3D1-2, Studies of Wavelength-Shifting Liquid Filled Quartz Capillaries for Use in a Proposed CMS Calorimeter

B. W. Baumbaugh1, K. Ford2, M. McKenna1, D. Ruggiero1, R. Ruchti1, M. Vigneault1

1Physics, University of Notre Dame, Notre Dame, IN, USA
2Radiation Laboratory, University of Notre Dame, Notre Dame, IN, USA
Studies have been done and continue on the design and construction of a Shashlik detector using Radiation hard quartz capillaries filled with wavelength shifting liquid to collect the scintillation light from LYSO crystals for use as a calorimeter in the Phase II CMS upgrade at CERN. The work presented here focuses on the studies of the capillaries and liquids that would best suit the purpose of the detector. Comparisons are made of various liquids, concentrations, and capillary construction techniques will be discussed.

(17:10) N3D1-3, Study of the Glass and Glass Ceramic Stoichiometric and Gd3+ Heavy Loaded BaO*2SiO2:Ce (DSB:Ce) Scintillation Materials for Calorimetry Application

R. W. Novotny1, K.-T. Brinkmann1, A. Borisevich2, V. Dormenev1, M. Korjik2, D. Kozlov2, P. Orsich2, H.-G. Zaunick1, S. Zimmermann1

12nd Physics Institute, Justus-Liebig-University, Giessen, Germany
2Institute for Nuclear Problems, Minsk, Belarus
In the last forty years application of crystalline materials in ionizing radiation detectors has played a crucial role in the discovery of properties of matter and promoted a continuous progress in the detecting technique. Further concepts of the detectors at HEP experiments will require an unique combination of the material features, particularly in case of collider experiments. Crucially important becomes a minimal level of radiation damage effects under the electromagnetic part of ionizing radiation and energetic hadrons as well: low deterioration of the optical transmission, low level of afterglow and low level of radio-luminescence due to radio-nuclides to be generated due to nuclear reaction in the detector material. A systematic study of the radiation hardness of inorganic optical and scintillation materials have been performed. We concluded that both oxide and fluoride crystals which consist of atoms with atomic number less than 60 will be reasonably survivable in the irradiation environment of future experiments at colliders. In this study we focus on the study of cheap glass (BaO*2SiO2) and glass ceramics (DSB: Ce), which is obtained from this glass and capable for a mass production. The transparent glass ceramics contains nano-sized particles of Ba2SiO5, which significantly improve the scintillation properties. The material is produced in fiber geometry with dimensions 0.8 x 200 mm2 and used to construct a prototype of a SPACAL type sampling calorimeter with tungsten absorber. First results of the module test will be reported including the overall properties of DSB:Ce.

(17:30) N3D1-4, Potential of Non-Linear Optical Phenomena for Fast Timing in Detectors of Ionizing Radiation

M. Korjik1, E. Auffray2, O. Buganov3, A. Fedorov1, S. Nargelas4, O. Siidletskiy5, G. Tamulaitis4, S. Tikhomirov3, A. Vaitkevicius4

1RINP, Minsk, Belarus , Minsk, Belarus
2CERN, Geneva, Switzerland
3Stepanov Physics Institute, Minsk, Belarus
4Semiconductor Physics Department and Institute of Applied Research, Vilnius University, Vilnius, Lithuania
5ISMA, Kharkov, Ukraine
After the triumphal discovery of the Higgs boson at CERN, the development of experiments at Colliders remains the main stream in experimental high energy physics. Since the pile up becomes increasingly important with the collider luminosity magnification, timing becomes the key issue in the future detection of rare events. Unfortunately, the time resolution of the detectors currently in use in high energy physics experiments is limited by 50–70 ps due to spontaneous processes involved in the development of the response signal, which forms after the relaxation of carriers generated during the interaction. In this study, we investigate the feasibility of exploiting sub-picosecond phenomena occurring after the interaction of scintillator material with ionizing radiation by probing the material with ultrashort laser pulses. One of the phenomena is the elastic polarization due to local lattice distortion caused by the displacement of electrons and holes generated by ionization. The key feature of the elastic polarization is its short response time, which makes it prospective for using as an optically detectable time mark. The nonlinear optical absorption of femtosecond light pulses of appropriate wavelength is considered to be a tool to form the mark. The study was aimed at searching for inorganic crystalline media combining scintillation properties and non-linear absorption of ultra-short laser pulses. The nonlinear pump-and-probe optical absorption technique with of 200 fs laser pulses was used to study the effects in lead tungstate and garnet-type scintillator crystals.

(17:50) N3D1-5, Particle Detection Through the Quantum Counter Concept in Er$^{3+}$:YAG

C. Braggio

Physics and Astronomy, University of Padova, Padova, Italy

On behalf of the DORELAS Collaboration
We report about a novel scheme for particle detection that is based on the infrared quantum counter concept. Its operation consists of a two-step excitation process of a quasi-three level system, that can be realised in rare earth-doped crystals when a cw pump laser is tuned to the transition from the second to the third level. The incident particle raises the atoms of the active material into a low lying, metastable energy state, triggering the absorption of the pump laser to the higher level from which photon emission occur. In order to demonstrate the feasibility of such a scheme, we have activated a Er(0.5\%):YAG by means of a tunable Ti:Sa laser and detected X-rays from an electron gun through PMT detection of green photons. Such upconverted photons correspond to the transition from the Er$^{3+}$ level ${^4}$S$_{3/2}$ to the ground state manifold.