PMT and WLS activities at IHEP Vladimir Rykalin IHEP, Protvino CBM meeting JINR Dubna, October 2008

B M C Outline The main reached and expected characteristics of PMT FEU-Hive for CBM RICH. Designed earlier and new constructions of PMT. Lacks of designed construction. Main elements of new construction. Some measured characteristics of PMT-WLS film system.

B M C Reached and expected characteristics of PMT FEU-HIVE-1 #1 #8 #22 pr.#7 pr.#10 waiting External PMT diameter, mm 7.5 7, Photo-cathode diameter, mm 6 6, PMT length is, mm Photo-cathode: K 2 CsSb Quantum efficiency, 410 nm, % Effective number of dynodes 12 Nominal HV, kV Amplification ×10 6 5× Dynamical charge range, pC Noise current is, e/sec Capacitance, pF Power dissipation, mW Price, Euro/PMT 25 Pr. #7, Pr. #9 – prototype samples of PMT-HIVE photocathodes producted in PMT-HIVE-1 glass cases without dynodes systems.

B M C Common view of designed construction of PMT FEU HIVE-1

B M C PMT FEU-Hive-1 and HAMAMATSU PMT R1828 signals: 76ns signals from LED Signals from single photoelectrons

B M C Elements of Construction of PMT FEU-HIVE-1

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B M C The disadvantages of construction and production technology of PMT FEU-HIVE-1 Lead-in contacts (Kovar rings) leaving on outside surface of PMT case creates difficulties for connections to PMT contacts in case of photodetector plane. Technology of glass case-Kovar rings welding is very delicate process that demands the special equipment. Absence of this equipment leads to considerable marriage at carrying out of manual welding. Production of Kovar rings, preparation rings and glass cases to welding are not cheap and simple operations. Technology of evaporation of dynode active layer is very unstable. This items are cause of design of the new PMT FEU-HIVE-2 construction and changes of some technological operation.

B M C Elements of Construction of PMT FEU-HIVE-2

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B M C Elements of Construction of PMT- FEU-HIVE-2

B M C Elements of Construction of PMT FEU-HIVE-2

B M C Status of PMT FEU-HIVE-2 Construction (drawings) of PMT is designed. Elements of construction are in production. The new technology of evaporation of dynode active layer is designed.

B M C Vacuum camera for measurement of WLS efficiency

B M C Gain of different WLS film

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B M C Time characteristics of WLS film

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B M C Plan of works on PMT FEU-HIVE and WLS at 2008 and 2009 Production of the first samples of FEU-HIVE-2 -end Production of few tens samples -end 2009 of FEU-HIVE-2 and study their characteristics. Study of WLS film efficiency in -end 2009 the optical region 120nm-400nm. The main condition of performance of works is a financing of works.