Dr. Jiří A. Mareš Institute of Physics Academy of Sciences of the Czech Republic Prague 6, Cukrovarnicka 10 Czech Republic

Transcription

1 Presentation of Activities Dr. Jiří A. Mareš Institute of Physics Academy of Sciences of the Czech Republic Prague 6, Cukrovarnicka 10 Czech Republic

2 Experimental set-up for scintillation response studies using HPMT ORTEC model 672 MCA ORTEC Model 927 MCB Here, we use α-ray sources instead of γ-rays 241 Am (59.6 kev) excited lines of Cu, Rb, Mo, Ag, Ba, and Tb, 57 Co, 22 Na, 137 Cs and 60 Co α-ray sources 241 Am, 239 Pu and 244 Cm Q.E. [%] Quantum efficiency of the HPMT DEP Wavelength [nm] Pulsed height spectra

3 Photoelectron response of the HPMT Bias voltage at the Si PIN diode anode High voltage between the photocathode focusing electrodes and the anode Counts n = 1 n = 2 no bias -no voltage 20 V bias - 6 kv 40 V bias - 6 kv 40 V bias - 10 kv 40 V bias - 12 kv long n = 3 n = Channel number SIGNAL - no bias no voltage dark current, light - bias HV voltage signal appear - nominal bias voltage photoelectrons appear calibration is possible

4 Gamma-ray pulse spectra of 662 kev line of the 137 Cs source with YAG:Ce measured for different sample thickness 6000 Counts Sample thickness 1 mm 2 mm 5 mm 10 mm Arrows kev peak position Channel number These gamma-ray spektra show that YAG:Ce has lower photo-peak efficiency compared with LuAG:Ce (photopeak/compton edge ~ 0.26 for 10 mm thickness) due to lower density (4.55 g/cm 3 ) it is necessary to use longer crystals (lower attenuation than has LuAG:Ce) YAG:Ce could be efficient for detection with the avalanche photodiodes

5 HPMT se-up at CERN developed during late nineties of past century for scintillation characteristics of large PWO crystals

6 Carmelo D Ambrosio shows the HPMT set-up Carmelo Jiri

7 Measurements at CERN Ing. A. Beitlerová

8 HPMT scintillation set-up at the Laboratory of Luminescence and Scintillation Materials in Prague

9 Projects are supported by the Czech Committee for cooperation with CERN (from Ministry of Trade and Industry or later by Ministry of education, Youth and Sport FZÚ Department of Optical Materials study of scintillation crystals RD-18 project Search for new radiation hard scintillators for new generation of electromagnetic calorimeters at LHC Crystals: Ce-, Pr-doped garnets, perovskites, silicates. PbWO 4 and other ones PHOS photon calorimeter Gamma a alfa spektroskopie scintilátorů

10 All-Russian Science Research Institute of the Experimental Physics - VNIIEF MECHANICAL DESIGN of the PHOS CRADLE PHOS CRADLE Project - schema General information The overall dimensions of the PHOS Cradle. The total weight is around 3,5 t

11 End of 2004 year CRADLE produced at TENEZ factory in Chotebor, Czech Republic

12 JUNE PHOS CRADLE assembled at CERN Point 2 by people from TENEZ factory TENEZ people MARES

13 PHOS CRADLE is moving down into experimental position CERN, Point 2, St. Genis CRADLE Rollers

14 PHOS CRADLE in the final position below the collision space of ALICE LHC experiment PHOS CRADLE

15 PHOS CRADLE position November 2008 Point 2 ALICE LHC

16 Detail of PHOS CRADLE November 2008 ALICE LHC

17 Works on or around PHOS CRADLE are not easy

18 CERN Point 2 ALICE LHC space with Martin Faltys Jiri Martin

19 One PWO module is in the centre of PHOS CRADLE holder module

20 With Dmitry Budnikov from VNIIEF in Sarov at PHOS assembling hall at CERN Dmitry Budnikov from Sarov Jiri from Praha

21 With Karel Polak at the read side of one PHOS PWO module at the assembling hall at CERN Karel Polak Jiri Mares

22 Front side of one of the PHOS PWO modules - individual PWO crystals are clearly seen

23 CERN - November 2009 control screen of PHOS detector at the ALICE CONTROL ROOM at Point 2

24 CERN - Point 2 November 2009 ALICE CONTROL ROOM - PHOS CONTROL Petr Zavada Jiri Mares

25 CERN Point 2 November PHOS control New start of LHC and first collisions

26 CERN Point 2 ALICE CONTROL ROOM first collision November 23, 2009

27 CERN Point 2 ALICE CONTROL ROOM people see first ciollisions

28 CERN picture of inner part of LHC, especially Of magnets