All three BPMs must have the same spatial resolution. The resolution can be estimated in terms of dynamic range as follows; 2 nm in 1 um dynamic range which is expected by 0.2um in 100um range which has been achieved with the BINP-BPMs. Therefore, the three BPMs must be aligned in a line within 1 um. Also a tilt control must be very important, with which offset-signal appears even beam goes through the center.
Major concerns are beam position jitters at the ATF beam; 3~4 um in X, 2~3 um in Y at several ~ 100Hz; there is a dominant oscillation at 100Hz from AC power, anyway.
In future, the nanometer BPM can be used in fast feedback system at IP. Even at ATF, they can be used in FEATHER or FONT feedback system.
X-band cavity BPM (low power model) has been constructed at SLAC. Performance was verified, however there was a vacuum leak. Marc Ross asked KEK mechanical center for fabrication of the high power version.
The x-band BPM will be constructed by KEK mechanical center (Funahashi ). The BPM has been designed by SLAC and it has the common mode cancellation . Naito who is at SLAC collaborates with Marc Ross on the BPM.
----------------------------------------- SLAC/Livermore 2003 30 May - 13 June? Fiducialization of three BINP-BPMs and electronics test by ATF beam 1 July Shipment of the BPMs to SLAC if residual radiation is OK. - October Assembling the BPMs in the support tube 6 October? Shipping of the three BPMs and the support tube to KEK - 20 Oct. Setup the three BPM system at ATF 20 October ATF will restart the operation. - Dec. Beam test 2004 Jan. - March Beam test with the x-band BPM? KEK 2003 Now - 16 June ANSYS calculations on the Livermore support tube, and results will be presented and discussed at ISG10 meeting. - 26 May List up specifications of support system for nano-BPM. 26 May - 1 Sep.? Design of KEK support system based on the specifications including FEM analysis Sep. Review the KEK design by ours, SLAC and Livermore now - Oct. Fabrication and test of low power model of c-band BPM Oct. - 2004 Feb. Fabrication of c-band BPM based on the low power model (One BPM is already funded, we would like to fabricate two more BPMs if funded.) Oct. - 2004 Feb. Fabrication of the KEK system if it is funded. 2004 March - April Setup the KEK system at ATF, which is preferable at difference place without interference to the support tube. If the KEK system is not funded, March - April Assemble the c-band BPM(s) in the support tube? April - June Beam test -----------------------------------------