High Light Yield PbWО4 Scintillation Crystals
Development of Large Size and High Light Yield PbWO4 Scintillation Crystal for Electromagnetic Calorimeters of Future Kaon Experiments
Tech Area / Field
- PHY-PFA/Particles, Fields and Accelerator Physics/Physics
- INS-DET/Detection Devices/Instrumentation
- MAT-SYN/Materials Synthesis and Processing/Materials
3 Approved without Funding
Joint Institute of Nuclear Research, Russia, Moscow reg., Dubna
- Institute for Nuclear Problems, Belarus, Minsk
- Saga University, Japan, Saga\nKEK High Energy Accelerator Research Organization, Japan, Tsukuba
Project summaryThe primary goal of this project is to develop new detectors for future kaon experiments based on new generation of bright and fast lead tungstate PbWO4 (PWO) scintillation crystals. These kaon experiments starting from KEK E391a have a goal to find a source of CP violation caused by physics beyond the standard model so to understand the matter-antimatter asymmetry in the universe.
The first step - a pilot experiment, E391a, at the KEK 12-GeV Proton Synchrotron was normal completed. Like second step is planned KOTO (E14) experiment at J-PARC (Japan Proton Accelerator Research Complex, Tokai, Ibaraki).
For beginning of E14 it is proposed to move the E391a setup to J-PARC and provide necessary modification based on experience with E391a.
Mainly is necessary to modify two calorimeters, main CsI and CC03. More appropriate CsI crystals will be provided by USA. The CC03 is the veto-detector located inside the CsI calorimeter. It must perform two main functions: to support the upper part of the calorimeter and to be a sensitive volume in order to reject the backgrounds events. In common sense it is better to use crystals for the CC03 detector.
Recent progress in scintillation materials engineering gives new opportunities in design of detector systems for particle and high energy physics. One of perspective options is PWO scintillation material which is the most popular scintillation material in high energy physics through its application at LHC projects, namely CMS and ALICE. Recently a modification of lead tungstate, named PWO-II, has been chosen by PANDA Collaboration to construct its electromagnetic calorimeter consisted of 16000 scintillation crystals.
Within the frame of this project the high light yield PWO-II scintillation crystal will be optimized and large size crystals will be grown by Czochralski method with platinum crucibles in high-frequency induction ovens using stoichiometric high-purity raw materials. 36 unique PWO scintillation crystals with size 2,2х2,2х30cm3 and 36 crystals with size 2,2х2,2х20cm3 produced under the project will be used to construct experimental detector module CC03 (Collar Counter) for KOTO (E14) experiment at J-PARC.
Upon fulfillment of the project, this PWO detector module will be installed at J-PARC and evaluated along with conventional CC03 CsI detector module.
The set aims require improving both PWO crystal growth technique (initial charge composition, optimal concentration of initial dopings of La and Y, feed material synthesis depth) and further crystal processing (main annealing conditions for the crystals, mechanical cutting, lapping and polishing). La and Y doping concentration in the long crystal will optimized in course of concentration series growing processes (up to ten) to provide required time and spectral characteristics, highest light yield and crystal radiation hardness, acceptable production yield.
The developed technological and methodological approaches will allow preparing and conducting efficiently future large scale kaon experiments with scintillation PWO crystals for further study of CP violation. Study of CP violation caused by physics beyond the standard model is extremely important because it helps to describe the matter-antimatter asymmetry in the universe.
JINR. The leading organization JINR is one of world leaders in study of CP violation caused by physics beyond the standard model. JINR staff members have participated in experiments at CERN (NA48, CMS, ATLAS) at KEK(E391a, K2K, KOTO).
The staff, participating in this project, has good experience in experimental elementary particle physics, data analysis and signal processing methods, simulation, calorimetric method, study of rare processes, rare decays of K-mesons.
INP. Scientists of the institute took part in preparation and implementation of high-energy physics experiments at CERN(ALICE, CMS) and GSI (PANDA) in 1992-2008. The main activity was development of new scintillation materials to meet the unprecedented goals of new experiments. Lead tungstate scintillation crystal PWO was developed within the frames of ISTC projects ##354, 354B, 1718. INP played a key role in development of mass production technology, quality assurance means and certification of PWO. All principal characteristics of PWO scintillators were radically improved up to the level of CERN experiments requirements. Within the frames of ISTC project #3293 INP scientists took part in the development of large volume СаМоО4 scintillation crystal for double beta-decay experiment in Yang-Yang Korean National Laboratory.
Collaborators of the project are the High Energy Accelerator Research Organization KEK and Saga University, Japan. These organizations are represented by Profs. Takeshi Komatsubara (Collaborator Team Leader), Gei-Youb Lim, Tadashi Nomura and Takao Inagaki from KEK and Prof. Suzuki Shiro from Saga University. Experimental study of the calorimeter prototype will be performed at Japan.