Minutes of 30th FFIR meeting on 10/11/2001

The meeting was held in a room of 3-425 at KEK, 13:30-14:10, 10/11/2001. We discussed on new final focus system (longer L*) , and present status of support tube R&D.

(1) New final focus system (discussion)

N.Yamamoto just started to adjust longer L* by changing upstream Q's while final doublets are unchanged since Yesterday. He could change L* from 4.25m to 4.35m by adjusting only upstream Q's. For further change, he must adjust the final doublets together with sextupoles. Since he understood various knobs at this optics, he will optimize or maximize the L* until next meeting. He also calculate parameters such as field gradient of final doublets for the present case of L*=4.25m. The parameters will be passed to Tsuchiya-san for designing a superconducting final quadrupoles. With this configuration, backgrounds due to low energy beam-particles should be estimated at a dump line.

(2) Support tube R&D

He has been investigating a discrepancy between measured eigen frequencies and calculated ones. He directly looked at signals of accelerometers on the specimen while it was vibrated. Signal of the oscillator was very clear. However, the signals of accelerometers have high frequency noises. Especially, the signal on the top of the specimen was largely distorted at the first resonance. He suspected that the oscillator itself vibrated 3-dimensionally. So, he will try to fix it on floor.

The next meeting will be on 25 October (Thu.), 2001 13:30 - 15:00 at 3 gokan, 425.