MUCH - related activity at PNPI A.Khanzadeev, for PNPI team ● R&D on muon chamber for MUCH central part ● Test of the materials for chamber modules ● Preparations for test beam ● Test beam in PNPI

Pillars made by chemical etching from photo-resistant layer 4mm between pillars, diameter of each pillar - 300μm, height - 75μm GEM (5x5 cm 2 ) of CERN production It was used rolled mesh of Russian production for MICROMEGAS – stainless steel (wire - 32 μm in diameter, cell - 64μm). A.Khanzdeev, March_2009, GSI GEM+MICROMEGAS Present stage of R&D

A.Khanzdeev, March_2009, GSI At previous R&D stage we worked with He/CO2 and Ar/CO2 mixtures. New gas supply system allowed to study Ar/CO2/iC4H10, He/CO2/iC4H10, Ar/CF4/iC4H10, and He/CF4/iC4H Volts Small addition of isobutane gives huge effect. The same values of gas gain are reached at much lower HV. Almost twice less energy of discharge for the same value of gas gain He/CF4/iC4H10 (90/8/2) showed much lower spark probability in comparing to 2-component mixture. Gas gain of 2∙10 7 is reached at 450 V applied to the mesh and GEM (visible spark problems occurred at 480 V). Current design of FEE supposes gas gain value of 2∙10 4 which is reached at 300 V. Last point that we tried to measure was at 350 V (gas gain of ~ 2∙10 5 ) and during 30 hours we did not detect any sparks (in the picture the last point is result of extrapolation).

Radiation hardness of construction materials Co 60 (E=1.25 MeV) → two expositions of 390 krad and 5.3 Mrad After irradiation the emitted fractions were detected and analyzed by infrared spectroscopy method polyethyleneFR4kapton Red – 5.3 Mrad, blue -390 krad Coefficient of radiation degradation after dose of 5.3 Mrad kaptonnorilflanFR4 polyethylene Radiation degradation Coefficient of radiation degradation after dose of 5.3 Mrad A.Khanzdeev, March_2009, GSI

Prototype for beam test A.Khanzdeev, March_2009, GSI Two prototypes (10x10 cm 2 each) MICROMEGAS+GEM MICROMEGAS+TGEM Readout electronics – ALICE type

Anode structure:  2048 pads;  Pad size 1.5x 3 mm 2 ;  Working area 102x109 mm 2 ;  Gap between pads 0.2 mm;  Mask-pad overlap mm;  Through hole diameter 0.5 mm;  Board thickness 1mm A.Khanzdeev, March_2009, GSI Prototype chamber elements

PNPI test beam Almost parallel beam of 1 GeV protons Intensity /cm 2 s, duty cycle – 50% mm There is possibility to get test beam three times per year Beam at the PC1 Readout electronics – CROS3 A.Khanzdeev, March_2009, GSI

Plans for this year ■ Try He+Ar based gas mixture ■ Measuring the collection time for chosen working gas ■ Building two prototypes (MICROMEGAS+GEM and MICROMEGAS+TGEM) for beam test ■ Preparing electronics for beam test ■ Would be nice to start beam test at PNPI accelerator A.Khanzdeev, March_2009, GSI