1. KEK Test Results / Plans Akira SATO Osaka University, Japan

2. contents Cross talk of SCSF78 Fiber optimization KEK plan Attenuation length Beam test

3. Cross talk for SCSF78 Experimental data can be explained assuming that mean free path of primary photon is 460  m. 1.0GeV/c  1.0GeV/c proton  /p ratio 300  m  0.5 p.e.0.8 p.e.0.68 500  m  1.2 p.e.1.6 p.e.0.75 dE/dx 1.8 MeV/cm 2.6 MeV/cm 0.7 Sci-Fi Primary photon 1.0GeV/c  1.0GeV/c proton 300  m  1.92 p.e.2.77 p.e. 500  m  2.92 p.e.4.21 p.e. 300  m  0.55 p.e.0.80 p.e. 500  m  1.20 p.e.1.72 p.e. Experimental data Expected # of p.e. with 0  m MFP Expected # of p.e. with 460  m MFP From last KEK beam test results

4. Optimization of 3HF fiber Alan estimated the mean-free path (MFP) for absorption by 3HF of the primary scintillation light from the primary dopant p-terphenyl (pT). The absorption can be expressed as  I/I o = 10 -(  cd)  : the molar extinction coeff. in (moles per liter-cm) -1 at wavelength c : the concentration in moles per liter d : the distance in cm Attenuation length for the primary dye emission via 3HF absorption :  50  m for 1dye+3HF(1500 ) D0 tracker  21  m for 1dye+3HF(3500)  Very short for 3HF(5000) w/o 1dye At high concentrations, 3HF acts like a primary dopant ie, its coupling the the fundamental PS excitation is quite strong.

5. KEK and Osaka Plan Scintillating fibers had been deriverd to Osaka Univ. June 3rd  Standard primary(pT) + 3HF(2500ppm)  Standard primary + 3HF(3500ppm)  Standard primary + 3HF(5000ppm)  3HF(5000ppm) only 0.35mm , round, multi-clad, s-type We are planing to study :  Attenuation length  Aging of bending fiber  Light yield (beam test)  Cross talk (beam test)

6. Attenuation length Measurement has just started. Cracks in fiber reduce light yield. Need some quality control preliminary

7. KEK beam test June 25th - July 2nd @ KEK  2 beam line Photon detector  Hamamatsu R7899 MOD Extended Green Photocathode 1 inch diameter 10 stage Head-on Type Prismatic Window Light yield Cross talk Sci-Fi PMT (R7899)

8. summary The most suitable fiber for MICE scifi tracker will be selected by KEK studies. Candidates :  Standard primary(pT) + 3HF(2500ppm)  Standard primary + 3HF(3500ppm)  Standard primary + 3HF(5000ppm)  3HF(5000ppm) only Attenuation length Aging Light yield Cross talk  Beam test : June 25th - July 2nd @ KEK-PS  2