1. Neutron Flux Measurement at the CYRIC T. Horiguchi and A. Ishikawa (Tohoku University) For the FPCCD group

2. CYRIC is the CYclotron Radio Isotope Center at Tohoku University which provides proton or heavy ion beams whose energy is upto 100MeV for proton, and 212MeV for Ar. Up to ~3uA is possible for proton beam with 70MeV energy. We performed FPCCD neutron irradiation test from 15 th Oct to 17 th Oct. – 2 hour irradiation with 1uA for 6um FPCCD – (performance to be shown by Ito)

3. The Beam Line Primary protons not interacting with Li target are kicked out to beam dump Thick iron shield surrounding the beam pipe. The beam port is square – 7.7 x 7.7 cm FPCCD is located about 1.2m far from Li target downstream upsteam

4. Neutron Beam Neutron Beam is produced from 70MeV proton beam using “Li + p  Be + n” reactions. – ~8mm thick Lithium target made by ourselves The neutron beam is almost monochromatic, about 65 MeV energy, and some tail. – using ToF method with Liq. Sci. by CYRIC.

5. Apparatus for Flux Measurement Liq. Sci. for absolute flux – 14cm  – efficiency was calibrated and known (given by CYRIC, around 10%). Beam profile monitor (BPM) for shape – Three plastic scintillators – Rectangular shape 1cm x 12.5cm – Pitch 1.2cm – Efficiency not known One large plastic scintillator for beam current calibration – ~10cm  – Located ~1m downstream from FPCCD FPCCD was placed in front of the beam port, liq. sci. and BPM was also located the same z position

6. Measurements Liq Sci covers beam port region – 2.62 x 10 7 Hz/uA for 14 cm  BPM is moved x and y direction to measure neutron rate in each position mm Liq. Sci.

7. Beam Profile projected onto x and y The profile is shifted to positive x direction. – The resolution of BPM placement is < a few mm, so we don’t know why (but it does not affect the neutron fluence to FPCCD) – We assume the beam is shifted to x direction The profile is almost flat for beam port region and also for shield region so we assume the rate is 2D step function, Beam port Beam flange Beam port

8. Flux Calculated flux at the beam port region – 3.3 x 10 5 Hz/cm 2 /uA Fluence – 2hours irradiation with 1uA – 2.4 x 10 9 /cm 2 Neutron fluence at the ILC in a year – 1.85 x 10 9 /cm 2 /year – Actually this value is somewhat old so we need to simulate with the latest accelerator and detector Corresponding to 1.3 years preliminary

9. Flux Comparison In CYRIC annual report, they quote 2*10 6 Hz/cm 2 with 3.5uA and 7mm t Li target –  5.7 x 10 5 Hz/cm 2 /uA Our measurement 3.3 x 10 5 Hz/cm 2 /uA About 2 times smaller. preliminary

10. Summary We measured the neutron beam profile for the cyclotron at the CYRIC and estimated the fluence to FPCCD – The fluence is 2.4 x 10 9 /cm 2 – Corresponding to 1.3 years at the ILC preliminary