20130221 Shift

• NOTE for this shift - the new laser-wire plic monitor will be in the data as tekm1 and tekm2. m1 is the peak voltage from the pmt - negative. m2 is the width of the signal - approximately 150ns. Didn't get time to set up a gate or an adc so this will have to do. For the timing overlap scans of phase the scope settings were changed and so m1 and m2 in these files are the peak and width of the apd signal. The scope was set back for the plic.

• Start 20:00

• Set file set13feb21_2003
• Detector saturated with settings from last week, but orbit incredibly flat.
• Likely due to the resteering through the machine with B3X earlier in the week being vertically rolled.
• 100 pulse log with machine as is 20130221_2004_log.dat

• QF21X was changed to 84.468A on 20th Feb day shift. Last week value was 65.929A. Setting to 65 unsaturates background. Must be due to beta function change.

• Access at 21:00 to align laser. Laser aligned ok and approximately 100mJ measured downstairs. No damage, everything looks fine. Energy meter fixed.

• Beam resumed 22:05
• Tuning linac phases individually in turn to maximise energy. Compensate with modulator #8 to achieve correct energy in the end.

• 100 pulse log with measured orbit 20130222_0231_log.dat
• Emittanace measurement, dispersion measurement done using FS tools. Also, measured tune using damping ring exciter and put in FS.
• Reoptimise orbit near LWIP as angle around -200urad vertically and -100urad horizontally. Usually go for less than 100urad in both.

Flight Simulator Twiss Parameters for Final Focus

Phase Timing 1	Phase Timing 2

Vertical Alignment	Horiontal Alignment

• Repeated Nonlinear Scan:
  

• Laser and Charge Normalised:
  

• Fitting again:
  

• Sigma Comparison:
  

• Suspiciously Small...:
  

So scans are returning very small values and also these values vary from fit to fit. There are a few points to address here:

• There are too many points on peak that could be weighting the fitting badly - should really program negative log likelihood instead of reduced chi2
• The points on peak are all very close together - the nonlinear scan points method really isn't perfect.
• +- 200um range is unnecessarily large and hides the interesting bits on peak in the plots

• Adjusted nonlinear scan points to have minimum step size of 0.35um vs 0.2um before.
• reduced number of points in scan to 50 and then to 40.
• increased number of samples to 20 then to 30 at each point to reduced error bars through statistics
• Reduced overall range of nonlinear scan to 150um total

So last of the nonlinear scans in the same place for now. Seems to be good with 40 - 50 samples points with new settings - 0.35um minimum step size, 150um range.

• Horizontal Scan for accurate horizontal size -> need for vertical fitting

• Set file: set13feb22_0718.dat
• Damping ring tune: H: 0.1718 V: 0.5644

• Charge ramp - 1000 pulse log 20130222_0731_log.dat
• Laser energy ramp - 1000 pulse log 20130222_0739_log.dat

Energy meter insists on producing serial port error, but then continues to receive data when you click ok - a totally pointless message. Contaminated last laser energy scan.

• 500 pulse laser energy on collision log - 20130222_0745_log.dat
• Background charge ramp - 1000 pulse log 20130222_0749_log.dat - no laser

• optimise green output at full power - green not too bad.
• go from 100us delay to 90us delay to increase signal to noise
• Energy meter reads about 103mJ.

4 vertical scans for different charge settings

• Fitted with sigma ex = 204.4um, m2=1 fits used as a physical upper limit on the size.
• 30 pulses, centre 756.7, 40 steps.

4 vertical scans for different laser settings

• Increase number of points this time
• Gun laser intensity back to 15%
• 30 pulses, center 756.7, 50 steps
• Fitted with sigma ex = 204.4um, m2=1 fits used as a physical upper limit on the size.

• Back to 70us flash lamp delay.
• High resolution vertical scan
• Long range horizontal scan

• Switch to OTR to measure same beam size.

• Resume Laserwire - straight back on collisions

• Quad scan +- 15 amps in 3 amp steps about centre
• Centre -90A

• Vertical: 5 pulses, 30um range, 10 steps
• Horizontal: 20 pulses, 2mm range, 40 steps
• Nonlinear scan: 30 pulses, 150mm range, 50 steps

• Initial Fit Plot Looks good...:
  

• Sigma Comparison:
  

• comparison zoom:
  

• Horizontal Scan:
  

• 20130222_0818_lws_xy_fit_plot.png:
  

• 20130222_0828_lws_xy_fit_plot.png:
  

• perhaps a little small:
  291.96 +-