KEK Test Results / Plans

Akira SATO

Osaka University, Japan

contents

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

Cross talk for SCSF78

Experimental data can be explained assuming that mean free path of primary photon is 460m.

1.0GeV/c

1.0GeV/c

proton/p ratio

300m 0.5 p.e. 0.8 p.e. 0.68

500m 1.2 p.e. 1.6 p.e. 0.75

dE/dx1.8

MeV/cm

2.6

MeV/cm0.7

Sci-Fi

Primary photon

1.0GeV/c

1.0GeV/c

proton

300m 1.92 p.e. 2.77 p.e.

500m 2.92 p.e. 4.21 p.e.

300m 0.55 p.e. 0.80 p.e.

500m 1.20 p.e. 1.72 p.e.

Experimental data

Expected # of p.e. with 0m MFP

Expected # of p.e. with 460m MFP

From last KEK beam test results

Optimization of 3HF fiber Alan estimated the mean-free path (MFP) for absorption by 3HF of th

e primary scintillation light from the primary dopant p-terphenyl (pT). The absorption can be expressed as

I/Io = 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 : 50m for 1dye+3HF(1500 ) D0 tracker 21m 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.

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)

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

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)

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