main injector & recycler dcct

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

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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

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SHUTDOWN SUMMARYRR Bergoz NPCT Installation

November 7, 2007 17

SHUTDOWN SUMMARYRR Bergoz NPCT Installation (2)

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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