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<TITLE>RE: [esa-t474] Draft 4.1</TITLE>
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<P><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">Hi Mark, some comments on the latest paper:</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">1. abstract. Need to state more clearly the following sentence: "We demonstrate sub micron resolution and micron level stability over 20 hours for a 1 m long BPM triplet and over an hour for a 40 m long baseline." Suggest something like "We demonstrate sub-micron BPM resolution and stability over 20 hours with a 1-meter long BPM triplet. We find micron-level stability over 1 hour for 3 BPM stations distributed over a 40-meter long baseline."</FONT></SPAN></P>
<P><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">2. introduction. Need a little more explanation on the LEP2 energy measurements. Note that their primary method used NMRs and resonant depolarization. The magnetic spectrometer had an accuracy (not resolution) of 170ppm, but required a calibration using resonant depolarization at lower energies. Note that most of the methods used at LEP2 can't be used at ILC. (can use information summary on this from slides 10 and 11 of </FONT></SPAN><A HREF="http://www.slac.stanford.edu/grp/rd/epac/Meeting/200612/woods.pdf"><SPAN LANG="en-us"><U><FONT COLOR="#0000FF" SIZE=2 FACE="Arial">http://www.slac.stanford.edu/grp/rd/epac/Meeting/200612/woods.pdf</FONT></U></SPAN></A><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">)</FONT></SPAN></P>
<P><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">3. introduction last paragraph. Rephrase and state better using active voice.</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">4. S2.1 line 108; "... To the electron North Damping Ring..."</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">5. S2.1, Fig. 4 caption "The beta functions and dispersion in the Aline and ESA..."</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">6. Figure 5 needs to be simplified. Use A28 etc. for correctors, C1 and C2 for collimators and WS1 and WS2 for wire scanners.</FONT></SPAN></P>
<P><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">7. Table 2; I'm still surprised the x jitter is that large, but perhaps it was. Do you have a plot of the jitter versus time for the 20-hour and 1-hour runs?</FONT></SPAN></P>
<P><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">8. S2.3 line 162-63; can you quantify how far from center of the BPM before get nonlinear effects?</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">9. S2.3 line 189: "...significant damage..."</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">10. S2.4 line 205: "...and phase adjustment is also possible."</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">11. S2.4 line 218: BPM32 signals are not split (SCP doesn't use these)</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">12. Figure 10 caption. Should note that sampling is at 119MHz.</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">13. S2.5 line 288: "occur"</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">14. S2.6 LVDT accuracy noted to be 6 microns on line 305. How well do LVDT and interferometer agree?</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">15. S2.6 line 312: "...with respect to interferometer heads on an aluminum table ..."</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">16. S2.6 line 315: "The interferometer heads are polarizing beam splitters that provide the ..."</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">17. Table 4: 2nd column should be for "total motion" not "rigid motion"</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">18. S2.6 line 329: "other"</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">19. S3.1 line 346 states that require 0.5mm offset to determine frequencies. This is an important point and would be good</FONT></SPAN></P>
<P><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial"> to elaborate a little. Would be good to quantify this more and perhaps distinguish what's needed for the lowQ versus</FONT></SPAN></P>
<P><SPAN LANG="en-us"> <FONT SIZE=2 FACE="Arial">highQ cavities. Would be nice if only 100-micron offsets or beam jitter could be used to get this.</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">20. Table 5, 3rd column should be w_y</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">21. Figure 12: vertical scale should be kHz?</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">22. S3.1 line 391: note of 100kHz change in BPM11x frequency. Was this corrected for the numbers used in Table 5?</FONT></SPAN>
<BR><SPAN LANG="en-us"> <FONT SIZE=2 FACE="Arial">Why wasn't it corrected for for later stability plots like Fig. 31?</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">23. Table 6 caption. Use resolution and drift rather than precision and accuracy.</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">24. S3.1 line 404: choosing sampling point where signal is decreased 10% is noted to ensure no monopole contamination; I need to be educated a little--how does this work? Different Q for monopole?</FONT></SPAN></P>
<P><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">25. S3.1 lines 413-414: "to minimize this effect by tuning both the reference and ..."</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">26. S3.2. I would start with the mover scan for BPM4 and then move to corrector scans, indicating that we use a scaling correction for corrector scans based on the BPM4 results for mover and corrector scale factors. </FONT></SPAN></P>
<P><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">27. Figure 13 should indicate which bpm is used. Also in caption and in a number of other places "negligible" is mis-spelled.</FONT></SPAN></P>
<P><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">28.</FONT><FONT SIZE=2 FACE="Arial"> S3.2.1 line 451 states that only use central 3 points of corrector or mover scans. I think we should be using all 5 points! Would be good somewhere in paper to </FONT></SPAN></P>
<P><SPAN LANG="en-us"> <FONT SIZE=2 FACE="Arial">note what we find for bpm linearity. I don't see any evidence of bpm saturation. And as you note later you're limited on scale factor uncertainties by the beam jitter;</FONT></SPAN></P>
<P><SPAN LANG="en-us"> <FONT SIZE=2 FACE="Arial">can improve that at least a factor 2 if use all 5 scan points.</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">29. S3.2; what are limitations to using beam jitter to get the IQ phase?</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">30. Figure 14, S3.2.2 and Eq. 19. Just go straight to using I and Q phases! We don't give any info on measuring beam slopes or tilts with the bpms so just avoid that here.</FONT></SPAN></P>
<P><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">31. S3.2.2 lines 494-497. Should note that this procedure effectively minimizes the bpm residuals.</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">32. SVD and minimization procedure. Since the procedure minimizes residuals it doesn't necessarily ensure no dependence of residuals on beam position in each of the</FONT></SPAN></P>
<P><SPAN LANG="en-us"> <FONT SIZE=2 FACE="Arial">cavities. What about a subsequent procedure that defines a chi**2 to minize that quantifies such a dependence??</FONT></SPAN></P>
<P><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">33. S3.2.2 last paragraph. This shouldn't be a cross-check it should (and I think you've implemented as such) be part of the standard procedure! You even note this is done</FONT></SPAN></P>
<P><SPAN LANG="en-us"> <FONT SIZE=2 FACE="Arial">in the 2006 results section.</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">34. S3.3 algorithm optimization. The necessary info should be put earlier in Section 3.1.</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">35. S3.4 should be described earlier, probably at end of Section 2 and then 2006 results noted in Section 4.</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">36. Table 9 should note this was for the 20-hour run? Is that true?</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">37. S4.1 Eq. 23 and line 566. Should note that sigma_i is the residual not the "combined resolution"</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">38. S4.1 lines 570-571: leave out (or even environmental data)</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">39. Table 10 is very useful. Suggest that column headings should be Measured Resolution, Electronics Noise, Vibration Noise (last column is added for bpm4 only). </FONT></SPAN></P>
<P><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">40. S4.1 lines 575-577. Why are 1x and 11x included in linked system if they have known problems? (though 11x can be corrected for)</FONT></SPAN></P>
<P><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">41. S4.2 Eq. 24: this should be put in Section 3 as part of the standard calibration procedure!</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">42. S4.2 lines 624-634 note problems with 1x and 11x. Why isn't 11x just corrected for and why are 1x, 11x included in the linked system?</FONT></SPAN></P>
<P><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">43. S4.2 line 640: "consistent"</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">44. S4.2 lines 642-647: tilt should be beam slope!</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">45. Fig. 18 notes limitations of using only central 3 points in calibration scans; why can't we use all 5?</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">46. For all plots that show changes in scales or IQ phase, should start them all at phase=0 and scale=1 at t=0 rather than forcing the averages to be 0 or 1!</FONT></SPAN></P>
<P><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">47. Figure 19: should note that these results are anti-correlated with Fig. 17. Strongly suggests there's a better calibration procedure!</FONT></SPAN></P>
<P><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">48. Figure 19a,c: would make much more sense if applied the frequency change correction.</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">49. Is Table 11 really needed? It's just the simple scaling noted in Eqs 25,26. Could summarize in text the results. Why is the x resolution for 1x in table 11 so large?</FONT></SPAN></P>
<P><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">50. S4.2 line 660: tilt should be beam slope.</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">51. Figure 21. Use BPMx1 rather than x41 (also Fig. 22). And in caption "between". Each point is for 1000-event block?</FONT></SPAN></P>
<P><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">52. Fig. 22. Why so few entries?? Why not for 1000-event blocks? Are all runs used? Only calibration runs??</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">53. S4.3. Relabel Section Heading to something like "Stability of BPM Offsets and Resolution</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">54. S4.3 line 675: "were significant". Does this indicate changes in scale or errors in scale determination??</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">55. Fig. 23. Horizontal scale should be mm, not microns? How is the plot generated and what do the error bars mean? Is this from 1000-event blocks?</FONT></SPAN></P>
<P><SPAN LANG="en-us"> <FONT SIZE=2 FACE="Arial">What happens if you make this plot over a short run where just have jitter and no drifts? Suggests that an improved calibration scheme to take out a correlation</FONT></SPAN></P>
<P><SPAN LANG="en-us"> <FONT SIZE=2 FACE="Arial">could work.</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">56. Figs. 23 and 24. Why does vertical scale go to -8 microns in Fig. 24 and only -6 microns in Fig. 23?</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">57. Fig. 25 caption: "between"</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">58. Figs 23, 28 and 33 are very useful. Would be good to elaborate on these and do more evaluation. Appear to be different regions in the plots, presumably corresponding</FONT></SPAN></P>
<P><SPAN LANG="en-us"> <FONT SIZE=2 FACE="Arial">to different time periods that have different scale calibration errors/changes.</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">59. Fig. 31; as stated before should just fix this frequency change for x.</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">60. S4.3 line 703: "…to remove the mechanical…"</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">61. S4.3 line 715: for linked system, should remove 1x and 11x (or fix 11x)…</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">62. Figure captions don't match figures for Figs 32-37</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">63. Figs 36-38 -- explanation or comment on different slopes??</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">64. no plot of linked residual over 20 hours is shown</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">65. Fig. 38 caption. First point is 100 MeV setpoint?</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">66. S5 conclusions line 743-744. Can we show a plot that demonstrates the cross coupling for BPM1?</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">67. S5 conclusions: need to note 1-meter and 40-meter baselines when discussing the results for each station and for linked statons.</FONT></SPAN></P>
<P><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">68. S5 concusions statements on upgrades. Note upgrades without stating "most major" or "most significant". Would be good to itemize them. Need to include also</FONT></SPAN></P>
<P><SPAN LANG="en-us"> <FONT SIZE=2 FACE="Arial">use of the Helmholtz coils for fast calibrations with correctors, so can avoid/reduce beam drift problems in corrector scan calibrations.</FONT></SPAN></P>
<P><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">mike</FONT></SPAN>
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<P><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">-----Original Message-----</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">From: Mark Slater [</FONT></SPAN><A HREF="mailto:slater@hep.phy.cam.ac.uk"><SPAN LANG="en-us"><U><FONT COLOR="#0000FF" SIZE=2 FACE="Arial">mailto:slater@hep.phy.cam.ac.uk</FONT></U></SPAN></A><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">]</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">Sent: Friday, November 02, 2007 3:41 PM</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">To: esa-t474@hep.ucl.ac.uk</FONT></SPAN>
<BR><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">Subject: [esa-t474] Draft 4.1</FONT></SPAN>
</P>
<P><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">Dear All,</FONT></SPAN>
</P>
<P><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">I've now finished going through the English and finalised the arguments for the last section on stability. As always, it can be found here:</FONT></SPAN></P>
<P><SPAN LANG="en-us"></SPAN><A HREF="http://cvs.hep.ucl.ac.uk/viewcvs/papers/esaBpmNote/built/?root=ILC+Accelerator+code"><SPAN LANG="en-us"><U><FONT COLOR="#0000FF" SIZE=2 FACE="Arial">http://cvs.hep.ucl.ac.uk/viewcvs/papers/esaBpmNote/built/?root=ILC+Accelerator+code</FONT></U></SPAN></A><SPAN LANG="en-us"></SPAN>
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<P><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">In order to try to get everyone to sign off on the last few plots, would it be possible to have a phone meeting after/instead of the ESA meeting on Monday? Mike/Yury, would you be able to sort the phone conference out if it's not already booked? Thanks! I'll also try to remember the UK clocks have gone back and phone in at the right time :)</FONT></SPAN></P>
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<P><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">Thanks,</FONT></SPAN>
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<P><SPAN LANG="en-us"><FONT SIZE=2 FACE="Arial">Mark</FONT></SPAN>
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