Minutes of First meeting, 13 May, 2003

I. Purpose

Primary purpose is to demonstrate a nanometer resolution in a configuration of three cavity BPMs at ATF extraction line.

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.

II. Present Status of Nanometer-BPM R&D

(1) SLAC and Livermore

Support system (tube and mover) will be constructed by Livermore which is called as support tube.
Three BINP BPMs should be sent to SLAC/Livermore until 1, July, however radiation survey must be executed.
Marc Ross et al will come to KEK on 30 May for 2 weeks in order to prepare a shipment of three BPMs. Alignment markers will be put on the BPMs by using the ATF beams for setting them in the Livermore's support tube. New electronics also will be tested. The electronics is based on a digital sampling, which has been designed by J.Frisch. The support tube with three BPMs will be installed at ATF in October, when the ATF beam will come back on 20, October.

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.

(2) KEK

There are five BINP BPMs, three of which will be sent to SLAC/Livermore and the other two have less Q-values.
A low power model of c-band cavity BPM will be constructed by Gakuin university . This BPM has two output ports to cancel a common mode, while the BINP BPMs have no such cancellation. The cancellation must be essential to achieve nanometer resolution. A high power BPM can be constructed within this fiscal year's money (1,500,000 yen).
Hayano is designing electronics based on an integration (analog) method, which is cheaper than the SLAC design, One set of electronic will be made in this summer.

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.

III. Study plan for the moment

(1) List up specifications of support table for nano-BPM

until 26 May, by Hayano

(2) Design a support system of three nano-BPMs in a line based on the specifications

by Higashi

(3) ANSYS calculations on static and dynamic properties of the Livermore structure.

by Yamaoka

(4) Communication with Marc Ross by Tauchi;

Tentative schedule is as follows;
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
Jan.   -  March    Beam test with the x-band BPM?

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.
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