PCAL Stripslight transmission properties

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For each layer only (longer) half of the stripsare measuring (shorter and longer are part ofthe same strip)

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Initial steps of measurements:Recording and source movement is automated, Glued 4 fibers to adapter, Optical grease (BC-630) contact with PMT, Not glued, no optical grease, Source moving steps 1cm, 10cm, KEITHLEY reading PMT anode current and recording average value (in 20, 100, 200 and 1000 time) in each step, One fiber in each hole, Cleaning holes by thin metallic bars, one and two together, After cleaning by metallic bars cleaning holes with Nitrogen, Cleaning fibers before inserting in the strip, Checking the plots during each measurements and comparing with reference plot, Rad. Source: 90Sr, 25 µCi, 5mm collimator.

To improve the quality of measurements: Moved PMT to opposite side of motor in the dark box, Grounding the aluminum profiles and wrapped PMT tube with Cu foil

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Final procedure for measurements:

Optical grease contact with PMT, Fibers are not glued to adapter, Step size 10cm, KEITHLEY reading 20 time at each position, Two fibers in each hole, Cleaning holes with Nitrogen, Cleaning fibers before inserting in to the strip (strip kept in vertical position, Checking the plots after each measurements comparing with reference plot.

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The ratio of PMT anode current at the end oflongest strip to background is: ~23

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Typical distribution

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Current ratio(last point to background)

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Comparison of measurements

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newreference

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Broken fibers

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A0 A1 - Intensity

α1 α2 - Attenuation (Short and Long)

Fitting functionfor attenuation calculation

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2110

xx

eAeAA

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Typical fitting(Length > 250cm)

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Length < 250cm

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Long and short attenuation lengths

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Ratio AL (2 exp case) toA (1 exp in Range > 250cm)

Fit to linear function C + tan(α)* XApril 26, 2011 20April 27, 2011 20

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Npe measurements

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Single photoelectron(peak parameters definition)

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Npe definition(under cosmic ray, deposit energy ≈2 MeV )

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