1. Fiber Attenuation Length Test for MINERvA Jaewon Park University of Rochester Jupiter/MINERvA Meeting, Sep 10, 2005

2. Introduction Attenuation length of Wave Length Shifting (WLS) fiber was measured 2004 summer Types of fiber / Tested fibers MINOS Fiber Scanner Light yield, Attenuation length  175ppm/300ppm, mirrored/unmirrored

3. Types of Fiber Single Cladding / Multi Cladding  Multi cladding has higher trapping efficiency Non-S type / S type  S type is stronger against bending Wave Length Shifting (WLS) Fiber  Type of Dye: Y7 / Y8 / Y11  Dye concentration: 150ppm / 200ppm Diameter: 1.2mm, 1.5mm  Smaller diameter fiber is easier to bend Core Inner Cladding Outer Cladding

4. Tested Fibers Kuraray, Multi Cladding, S type, Y11  150ppm, 1.2mm (out of old batch, measured but poor quality)  175ppm, 1.2mm  300ppm, 1.2mm  175ppm, 1.2mm, mirrored  300ppm, 1.2mm, mirrored Some of mirrored fibers were measured after cutting mirror again

5. List of Data 8-118-128-17 300ppm K300m12.001K300m12.301K300c12.001 K300m12.002K300m12.302K300c12.002 K300m12.003 K300m12.004 175ppm K175m12.001K175m12.301K175c12.001 K175m12.003K175m12.303K175c12.003 K175m12.004 Jun-18/20July-14/168-118-128-17 300ppm k300_12.000k300_12.10a k300_12.001k300_12.10b k300_12.30bk300_12.40b k300_12.002 k300_12.003 k300_12.004k300_12.10e k300_12.30ek300_12.40e k300_12.005k300_12.105k300_12.705k300_12.305 k300_12.006k300_12.106 k300_12.306 175ppm k175_12.000k175_12.100 k175_12.300 k175_12.001k175_12.101 k175_12.301 k175_12.002k175_12.102 k175_12.003k175_12.103 k175_12.004k175_12.104 k175_12.005k175_12.105 Mirrored fiber data

6. MINOS Fiber Scanner Hamamatsu R580-17 PMT Sr90 source Light Mixer PMT Ferrule Scintillator bar WLS fiber

7. Relative Light Yield 300ppm has higher light yield at d=0cm

8. Attenuation Length Remained fraction of light at d=318cm (i.e. shape of curve)

9. Mirrored Fibers Small sample size (two of each type)

10. Comparison with Previous Reflectivity Maybe need to make correction to old data

11. Fit values Fitted value from mirrored fiber can be used to extrapolate other values f(x) = A1*Exp(-x/L1) + A2*Exp(-x/L2)

12. More Thing To Do Try to fit mirrored double exponential curve Compare mirrored fiber data and other data  Two results are obtained by different code  Check consistency Estimate systematic error  Some discrepancy seem to rise from PMT gain shift