1. Philip Burrows ATF 15/03/05 FONT Group Progress + Plans 2005 Philip Burrows, Christine Clarke, Glenn Christian, Hamid Dabiri Khah, Stephen Molloy, Glen White (Queen Mary, University of London) Alexander Kalinin (Daresbury Lab.) Colin Perry (Oxford) Doug McCormick, Marc Ross (SLAC)

2. Philip Burrows ATF 15/03/05 General Strategy March 2005: Commission final version of superfast processor + jitter monitor June 2005: FONT3 closed-loop feedback tests with new amplifier During 2005: Develop prototype for FONT4 digital feedback system for ILC bunch spacing December 2005: First commissioning studies with prototype digital system March 2006: Possible first feedback tests with digital system + 3 ILC bunches

3. Philip Burrows ATF 15/03/05 FONT3 experiment outline Adjustable-gap kicker BPM ML11X Feedbac k Superfast BPM processor Superfast amplifier BPM ML12X BPM ML13X Aim: TOTAL latency < 20 ns

4. Philip Burrows ATF 15/03/05 FONT3: ATF beamline configuration kicker BPM ML11X

5. Philip Burrows ATF 15/03/05 FONT3 beam requirements 20-bunch train (56 ns) essential in order to see action of delay loop Uniform charge within train (better than +- 10%) essential since no time for charge normalisation Flat bunch-bunch vertical position profile within train desirable Small bunch-bunch vertical position jitter within train (few microns) essential Small train-train vertical jitter (c. ten microns) essential to avoid amplifier saturation (c. 50 microns)

6. Philip Burrows ATF 15/03/05 FONT3 jitter monitor Aim to measure bunch-bunch jitter at micron level First tests June 2004: bunches resolved, but position resolution > 10 microns (common-mode rejection issues) Improved processors tested December 2004 (BPMs 8, 10, 13) + 2 BPMs in ring + March 2005

7. Philip Burrows ATF 15/03/05 y position jitter correlation: extraction line - ring (FONT shift December 2004: 40 sequential 20-bunch trains) Offers possibility for jitter correction by feed forward from ring to extraction line ATF2 demands micron-level position stability at entrance to final focus

8. Philip Burrows ATF 15/03/05 Jitter Monitor Tuesday shift – 8/9 March 2005 (single bunch) –Measured delays between sum and difference signals using new synchronisation circuit, for BPMs 26 and 27 in ring and BPMs 8 and 13 in extraction. –BPM26 delay = -208 ps –BPM27 delay = 90 ps –BPM8 delay = 430 ps –BPM13 delay = -384 ps

9. Philip Burrows ATF 15/03/05 Calibration measurement for BPM26&27 –BPM 26 – 1.6877 –BPM 27 – 1.3381 Calibration for BPMs 26 + 27

10. Philip Burrows ATF 15/03/05 Friday shift – 12 Mar Multibunch mode –3 BPMs in Extraction line – BPMS 8,10,13 –Synchronisation data for BPM10 –Calibration data for all three BPMs Single Bunch mode –Exchanged BPM 10 in extraction line for BPM26 in ring –Took data to study correlation between jitter in ring and extraction line.

11. Philip Burrows ATF 15/03/05 Multi-Bunch Calibration ML8X ML10X ML13X 1712±111 V/m 2374±24 V/m 2104±20 V/m

12. Philip Burrows ATF 15/03/05 Multi-Bunch Resolution Residuals from fitted position at ML10X based on ML8X and ML13X for 100 consecutive pulses (at 0.7 Hz). Estimate of jitter at ML10X -> 3.1 um.