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Main Injector & Recycler DCCT. SHUTDOWN SUMMARY MI DCCT Pickup Modifications. Feedback loop NOW has 2 turns instead of 1. Calibration loop NOW has 2 turns instead of 1. A single turn calibration loop is available, but not connected. - PowerPoint PPT Presentation
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November 7, 2007 1
Main Injector & Recycler DCCT
November 7, 2007 2
SHUTDOWN SUMMARY MI DCCT Pickup Modifications
• Feedback loop NOW has 2 turns instead of 1. • Calibration loop NOW has 2 turns instead of 1.
A single turn calibration loop is available, but not connected.
• The dynamic range of the intensity reading is extended to 1.4A (9.8e13) with output readings remaining linear <4.5e13. – At 5e13, errors are <0.1%; at full-scale, errors
approach 0.5%.
November 7, 2007 3
4turn fdbk
2turn fdbk
2turn cal
DC Sense
AC Sense
Feedback2 (2turn)
Feedback 1 (2 turn)
Drive 1
Drive 2
November 7, 2007 4
November 7, 2007 5
November 7, 2007 6
November 7, 2007 7
MI PROBLEMS @STARTUP
WORK:• Tuned resistors
feedback loop to reduce slow oscillation
• Align pickup signal with demodulator clock signal
• Tuned DC_SENSE board 200Hz,600Hz notch filters
• Reduced gain at demodulator input by 1/2
November 7, 2007 8
10/24 vs. 10/25
0
0.1
0.2
0.3
0 60 120 180 240 300 360
Hz
e10
0
0.1
0.2
0.3
0 60 120 180 240 300 360
Hz
e10
200Hz noise reduced from 0.21e10rms (last year ~0.17e10rms) to 0.085e10rms.
November 7, 2007 9
CONDITION prior to access
November 7, 2007 10
11/6/2007 ACCESS SUMMARY MI DCCT Modifications
• Changed feedback burden resistor from 15Ω to 20Ω, decreasing dynamic range to1.05A (7.3e13).
• Moved front end input to a buffer amplifier channel with a 500Hz LPF & 200Hz notch filter. (500HzLPF only channel still available in buffer amplifier)– Reduces 200Hz noise; Increase rise time from
~500usec to ~3msec; Bench shows ~1% overshoot
• Calibration and frequency response tests
November 7, 2007 11
MI Wobble@ StartupWobble was not due to 200Hz noise as before. MI Ramp was affecting DCCT readout.
November 7, 2007 12
Also, Bad adapter to input filter
BEFORE
November 7, 2007 13
After removing bad adapter…
Effect of MI Ramp
Signal Frequency Content
November 7, 2007 14
20% difference in MI // RR transferVME front end got reset to previous value so did not take into account feedback resistor 15/20 change.
November 7, 2007 15
FINAL CONDITION
November 7, 2007 16
SHUTDOWN SUMMARYRR Bergoz NPCT Installation
November 7, 2007 17
SHUTDOWN SUMMARYRR Bergoz NPCT Installation (2)
November 7, 2007 18
November 7, 2007 19
Bergoz Performance During Bake
• Measured
-0.067 e10/degC • Expected
0.035 e10/degC (5uA/degK)
November 7, 2007 20
11/6/2007 ACCESS SUMMARY RR DCCT Modifications
• Moved front end input to a buffer amplifier channel with a 500Hz LPF & 200Hz notch filter. (500Hz+200&600Hz notch filtered channel still available in buffer amplifier)\
• Calibration and frequency response tests
November 7, 2007 21
Observed Effect of MI Ramp
November 7, 2007 22
RR Bunch Length Dependence
November 7, 2007 23
November 7, 2007 24
Linear Sweep Frequency at RR Calibration Port
November 7, 2007 25
R:BCBEAM to filter out 60Hz
November 7, 2007 26
Old Bergoz Unit Failing