Tile and fibre measurements (Tile HCAL) J. Cvach, S. Němeček Institute of Physics AS CR, Prague (Calice Coll.) 1.Tile uniformity, current measurements 2.Cosmics monitor 3.Comparisons 4.Conclusions

ECFA-DESY, St. Malo 13/04/02 J. Cvach: Tiles & fibres...2

ECFA-DESY, St. Malo 13/04/02 J. Cvach: Tiles & fibres Tile uniformity with source measurement Our setup consists of light tight box + PM Hamamatsu R5505 at 2 kV + Keithley 6514 electrometer + 90 Sr (~ 1.5 MBq) radioactive source has a fixed grid for uniformity measurements: - multiples of 4 mm in x direction - 10 mm in y direction Uniformity = / calculated over area smaller by ~10 mm than tile size (due to the source profile), – STD of one meas. Different tile sizes: Bicron bc908 tiles 5x5, 10x10, 15x15 cm 2 (read by fiber bc91A mc, 0.8 mm thick): Different grooves, tile size 5x5 cm 2, Kuraray SCSN81 - middle, edge, diagonal groove - 1 and 2 circular grooves (read by fiber bc91A) Result: no dependence of uniformity on tile size observed

ECFA-DESY, St. Malo 13/04/02 J. Cvach: Tiles & fibres...4 Setup for uniformity measurements

ECFA-DESY, St. Malo 13/04/02 J. Cvach: Tiles & fibres...5 Example: tile with middle groove fiber on side fiber in groove Groove effect not masked by source profile PM

ECFA-DESY, St. Malo 13/04/02 J. Cvach: Tiles & fibres...6 Summary for tile Kuraray SCSN81 5x5 cm 2 Worse Corner Best Corner

ECFA-DESY, St. Malo 13/04/02 J. Cvach: Tiles & fibres...7 Example: tiles bc408 - uniformity PM 10 x 10 cm 2 Tile (cm 2 ) 5 x 5 10 x x 15 Uniformity (%)4.0 – – – 5.5 no dependence on size! PM 15 x 15 cm 2 fibre on side

ECFA-DESY, St. Malo 13/04/02 J. Cvach: Tiles & fibres...8 Tile+fiber response to 90 Sr – source in the tile centre

ECFA-DESY, St. Malo 13/04/02 J. Cvach: Tiles & fibres...9 Tile+fibre response to 90 Sr – cont.

ECFA-DESY, St. Malo 13/04/02 J. Cvach: Tiles & fibres Cosmics monitor Two plastic scintillator bars, 50 cm long, 5*2 cm ² ( detector : Up, Down) – separated vertically by 2.5 cm thick Pb bar (larger E μ for Coinc.) => ~E loss of MIP – read by PMTs EMI 9813 (d=46mm, 14 dynodes) – connected by PMMA (Plexiglas) lightquide: 5*2 cm ² => π*(2.3 cm) ² Sliding Up detector the Test area L*5 cm ² is prepared : – Three optically separated Scintillator tiles Bicron BC-408, 5*5 cm² – Two optically separated Scintillator tiles Bicron BC-408, 15*15 cm² – Read by PMTs HAMA H3165 (d=10mm, 10 dynodes) μ

ECFA-DESY, St. Malo 13/04/02 J. Cvach: Tiles & fibres...11 Cosmics monitor, DAQ PULSER from Dual Timer CAEN, N93A LRS 2249W CAMAC to PC by KK Ohm Gate Left Right Delay Down Up Delay Linear FAN-OUT 428A Pulser LRS Hz 300 ns LRS 623A

ECFA-DESY, St. Malo 13/04/02 J. Cvach: Tiles & fibres...12 Scintillator Tiles BICRON bc408 spectra Right PMT Left PMT μ 30% 29%

ECFA-DESY, St. Malo 13/04/02 J. Cvach: Tiles & fibres...13 N pe from left and right PM N pe.: C * ² σ(L-R) ² - σ 0 2 C = up to 1.25 to correct for statistical fluctuations in the first few dynodes ( C=1 used) σ 0 = Noise ( neglected) E.H.Bellamy,..,S.Tokar,..NIM A339(1994)468 CUT (L+R) > 6

ECFA-DESY, St. Malo 13/04/02 J. Cvach: Tiles & fibres...14 Corespondance of LY and cosmics - bc408 3 tiles 5x5, 3 tiles 10x10, 2 tiles 15x15 cm 2 used in cosmic measurements Light yield measured - Sr source in the middle of the tile 2 fibres Kuraray Y11(200), 1 mm with mirror on tile side, Tyvek, Alu reflect. Results per tile & fibre Tile a x a (cm 2 ) 5 x 510 x x 15 LY (nA) Relative LY Photo e *) LY / photo e - (nA) approximate scaling 1/a observed in ATLAS collaboration our normalization factor = 16 nA/ photo e - *) cf. to 6.57 given in S. Reiche, Diploma thesis, Hamburg 2001

ECFA-DESY, St. Malo 13/04/02 J. Cvach: Tiles & fibres...15 Comparison of LY measurements DESY – effort made to have collimated Sr source, hand device ( ) Prague – Sr source with divergence of ~ 45 o, semiautomatic device, grid 10 mm x 4 mm ( ) each data sample normalized to its max value PRG – fibre on side PRG fibre end

ECFA-DESY, St. Malo 13/04/02 J. Cvach: Tiles & fibres...16 LY comparison - comments DESY subtracts correction ~ 6-10 % which is x dependent, not y dependent PRG no corrections, background dark current < 2% and not x, y dependent PRG: tile position in coordinate system known to +- 2 mm for x, y DESY: tiles in Tyvek, mirrored fibre end PRG: tiles in white paper, fibre end cut and not mirrored PRG: LY increases toward fibre end DESY measurements: smaller decrease towards tile edges – collimated source DESY meas: symmetric in x, understanding of x dependent correction? --> DESY measurement: better uniformity PRG: try to collimate source or unfold the source profile

ECFA-DESY, St. Malo 13/04/02 J. Cvach: Tiles & fibres...17 Comparison measurement of attenuation length for bc408 scintillator (Kuraray Y11 fibre) left: S. Reiche, Diploma thesis, bc408 (box), Kuraray SCSN (triangle), 5x5cm 2 right: this talk, bc408, 15x15 cm 2 Measurements consistent: drop ~ 6% at 4 cm

ECFA-DESY, St. Malo 13/04/02 J. Cvach: Tiles & fibres Conclusions Measurements with radioactive source and cosmic muons provide consistent results Cosmic muon measurements confirm assumption from TDR about N pe Uniformity of different tile geometries/sizes < 7 % Comparison of measurements from different labs important Simulation needed to better understand measurements/ improve design Fiber on tile side is a recommended option but fiber in circular groove gives 3x larger LY (option for larger tiles?)