Beam Position Monitors FAC Review October 29 31

Beam Position Monitors FAC Review October 29 -31, 2007 • Stripline BPM Performance and AFE Modifications • Cavity BPM Electronics • BPM Digitizer Comparison October 29 -31, 2007 Beam Position Monitors 1 Ron Johnson ron_johnson@slac. stanford. edu

Stripline BPM Performance and AFE Modification October 29 -31, 2007 Beam Position Monitors 2 Ron Johnson ron_johnson@slac. stanford. edu

BPM Performance Take data synchronized pulse-by-pulse Use linear prediction of each BPM from adjacent BPMS Example: Compare bunch charge pulse 300 pulses 17 BPMs Average rms/mean 0. 0007 May include pulse -pulse variation in losses October 29 -31, 2007 Beam Position Monitors 3 Ron Johnson ron_johnson@slac. stanford. edu

Performance Predict BPM position reading from linear fit to adjacent BPMs (model-independent) October 29 -31, 2007 4 300 machine pulses Beam Position Monitors Effective beam charge 0. 35 n. C sx = 2. 5 Ronmicrons Johnson sy = 1. 7 microns ron_johnson@slac. stanford. edu

BPM Performance Q~ 200 p. C Resolution requirement is 10 microns for the small aperture BPMs Meets resolution requirements October 29 -31, 2007 Beam Position Monitors 5 Ron Johnson ron_johnson@slac. stanford. edu

AFE Modifications CAL – Additional switch to improve isolation CAL – Add on/off control to oscillator CAL – Replace BP filter with packaged unit Chan – Replace 2 nd attenuator with 0 -31 d. B unit Chan – Put anti-alias BP filter on the PCB Revise limiter Revise layout and connectors October 29 -31, 2007 Beam Position Monitors 6 Ron Johnson ron_johnson@slac. stanford. edu

Status Plan to build 53 modules for BSY/LTU/Dump. Includes 3 spares for the injector. And 3 modules for sector 24/25 (at the request of the commissioning team). Installation in January. Most parts for AFE, PAD, and Clock Board on order (certainly long lead items). Bulk of modules ready for installation in March/April. October 29 -31, 2007 Beam Position Monitors 7 Ron Johnson ron_johnson@slac. stanford. edu

Cavity BPM Electronics October 29 -31, 2007 Beam Position Monitors 8 Ron Johnson ron_johnson@slac. stanford. edu

LTU and Undulator BPM System Specification Parameter Specification Limit Condition Resolution < 1 m 0. 2 – 1. 0 n. C +/- 1 mm range Offset Stability < +/- 1 m 1 hour +/- 1 mm range 20. 0 +/- 0. 56 Celsius Offset Stability < +/- 3 m 24 hours +/- 1 mm range 20. 0 +/- 0. 56 Celsius Gain Error < +/- 10 % +/- 1 mm range 20. 0 +/- 0. 56 Celsius Dynamic Range, Position +/- 1 mm 10 mm diameter vacuum chamber Dynamic Range, Intensity > 14 d. B PC Gun 0. 2 – 1. 0 n. C October 29 -31, 2007 Beam Position Monitors 9 Ron Johnson ron_johnson@slac. stanford. edu

Cavity BPM Electronics October 29 -31, 2007 Beam Position Monitors 10 Ron Johnson ron_johnson@slac. stanford. edu

VME ADC Module October 29 -31, 2007 Beam Position Monitors 11 Ron Johnson ron_johnson@slac. stanford. edu

BPM Digitizer Comparison Steve Smith August 8, 2007 October 29 -31, 2007 Beam Position Monitors 12 Ron Johnson ron_johnson@slac. stanford. edu

Analysis CW input from RF generator Through 140 MHz bandpass filter to reduce generator harmonics Digitize Plot spectrum Find apparent frequency from data Fit sine curve to data Look at residuals to fit Compare phase noise October 29 -31, 2007 Beam Position Monitors 13 Ron Johnson ron_johnson@slac. stanford. edu

VME Digitizer @ -1 d. BFS Fit good to 6. 5 ADC counts rms ENOB = 11. 5 Harmonics <-80 d. Bc October 29 -31, 2007 Beam Position Monitors 14 Ron Johnson ron_johnson@slac. stanford. edu

VME digitizer PAD @ -1 d. BFS Fit good to 16 ADC counts rms ENOB = 10. 2 Harmonics <-72 d. Bc October 29 -31, 2007 Beam Position Monitors 15 Ron Johnson ron_johnson@slac. stanford. edu

Compare Noise floor Harmonic distortion Other lines in spectrum Input range October 29 -31, 2007 Beam Position Monitors 16 Ron Johnson ron_johnson@slac. stanford. edu

Digitizer Comparison Parameter VME PAD Comments Amplitude -1 -12 d. BFull. Sscale Rms fit error 6. 5 4. 2 16 7. 1 ADC counts ENOB 11. 5 12. 1 10. 2 11. 3 Bits (ref Full Scale) Worst harmonic -80 -85 -72 -68 d. Bc Phase noise (full spectrum) 0. 013 0. 031 0. 53 1. 9 degrees (includes harmonics) (PAD dominated by 2 nd harmonic) Phase noise (<20 MHz) 0. 008 0. 014 0. 021 degrees VME 5 d. B better on noise floor VME 8 d. B better on worst harmonic October 29 -31, 2007 Beam Position Monitors 17 Ron Johnson ron_johnson@slac. stanford. edu

Comparison Simplification Reduces the number of accelerator ethernet ports, private ethernet ports, and DIGI ports. Communication with the ADC is over the VME backplane. PAD would require enclosure and PS not yet designed. Simplifies clock distribution (10 vs 18 d. Bm input) Performance Reduces broadband noise and harmonics. FPGA has more computing power than the Coldfire. Comparable data transfer rates ( measured 28 Mbytes/s for VME ADC). Software Both would need modification of the IOC software. VME ADC needs a driver. October 29 -31, 2007 Beam Position Monitors 18 Ron Johnson ron_johnson@slac. stanford. edu

Status Two VME ADC modules produced and tested. Production of 40 additional modules to start in November. Cable plant is designed and in CAPTAR. Clock and LO distribution is being designed (Andrew Young). Power supplies and power distribution is being designed (Steve Smith). Hardware and software will be ready by April. October 29 -31, 2007 Beam Position Monitors 19 Ron Johnson ron_johnson@slac. stanford. edu

AFE Modification (Additional Slides) October 29 -31, 2007 Beam Position Monitors 20 Ron Johnson ron_johnson@slac. stanford. edu

AFE Modifications October 29 -31, 2007 Beam Position Monitors 21 Ron Johnson ron_johnson@slac. stanford. edu

Calibration Calibrate through BPM Via stripline-stripline coupling Performance not yet verified October 29 -31, 2007 Beam Position Monitors 22 Ron Johnson ron_johnson@slac. stanford. edu

CAL Modifications October 29 -31, 2007 Beam Position Monitors 23 Ron Johnson ron_johnson@slac. stanford. edu

RF BPM Analysis Steve Smith September 5, 2007 Updated Oct. 26 October 29 -31, 2007 Beam Position Monitors 24 Ron Johnson ron_johnson@slac. stanford. edu

Procedure Calibrate with 2 mm scans: LCLSscan_Horiz_Cal_200 pc_2000 um_Vert. Offset 3 mm_1_High. Gain-2007 -232 -0820131859. x. sdds LCLSscan_Vert_Cal_200 pc_2000 um_Vert. Offset 3 mm_1_High. Gain-2007 -232 -0820131157. y. sdds Check against other calibration scans Analyze LCLSscan_Vert_Cal_200 pc_200 um_Vert. Offset 3 mm_2_High. Gain-2007 -232 -0820161336. y. sdds Take 1 st 50 pulses to fix BPM-to-BPM alignment Predict X 2 = linear combination of (X 1, Y 1, X 3) Y 2 = linear combination of (X 1, Y 3) For remaining events 25 October 29 -31, 2007 Ron Johnson Beam Position Monitors Compare ron_johnson@slac. stanford. edu (X 2, Y 2) to predictions from (X 1, Y 1, X 3, Y 3)

Calibration October 29 -31, 2007 Beam Position Monitors 26 Ron Johnson ron_johnson@slac. stanford. edu

Check Calibration Scales Analyze two more independent sets of calibration data Confirms scale Note apparent mover inconsistency for last step of X scan October 29 -31, 2007 Beam Position Monitors 27 Ron Johnson ron_johnson@slac. stanford. edu

Data Set In middle of run beam (mover? ) changes Position jumps ~200 microns Apparent beam angle changes October. Study 29 -31, 2007 only first 150 pulses Ron Johnson 28 Beam Position Monitors ron_johnson@slac. stanford. edu

X sx = 360 nm October 29 -31, 2007 Beam Position Monitors 29 Ron Johnson ron_johnson@slac. stanford. edu

Y s. Y = 270 nm October 29 -31, 2007 Beam Position Monitors 30 Ron Johnson ron_johnson@slac. stanford. edu

Resolution Conclusion Both X & y resolution are below 500 nm Movers are a pain Beam jitter is troublesome Requires large scans to get a calibration Should move BPMs independently Then beam jitter doesn’t affect calibration October 29 -31, 2007 Beam Position Monitors 31 Ron Johnson ron_johnson@slac. stanford. edu

Stability Tests (Sept. 6) October 29 -31, 2007 Beam Position Monitors 32 Ron Johnson ron_johnson@slac. stanford. edu

Check Short Term Stability Data: LCLSsynchlog_200 pc_Horiz_00 um_Vert_3000 um_1_High. Gain-2007 -232 -0820132521. sdds 1000 points at 6 Hz Digitizer trigger glitch points removed Y steering during first 30 points, ignore them Alignment fit to next 50 points Drift, resolution taken from remaining ~900 pulses Resolution: s. Y = 380 nm sx = 440 nm Drift ~ 200 nm in X, less than 100 nm in Y in 2. 5 minutes October 29 -31, 2007 Beam Position Monitors 33 Ron Johnson ron_johnson@slac. stanford. edu

3 Hour Cruise LCLSslowlog_1 Hour. Stab_4 -2007 -2340822 - 161515. sdds 30 pulses every minute 5345 pulses total ~ 3 hours Many multi-mm jumps pulses 350 and 700 Clock seems unlocked from 390 to 490 Ignore first 700 pulses Use next 150 pulses (5 min) of data for alignment Estimate resolution and drift from remaining pulses Resolution: s. X = 1. 6 microns s. Y= 1. 9 microns Drift: Look at fit residual plots (Vertical axes are in mm) October 29 -31, ~5 2007 microns in X Beam Position ~3 Monitors microns in Y 34 Ron Johnson ron_johnson@slac. stanford. edu

Stability Conclusions Stability results are almost good enough Probably need better calibration Maybe mechanical stability Calibration is from 2 days prior to stability run ? ? ? October 29 -31, 2007 Beam Position Monitors 35 Ron Johnson ron_johnson@slac. stanford. edu