Update in longitudinal damper system in MI

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Update in longitudinal damper system in MI

• Hyejoo Kang
• Stanford University
• Status of transverse longitudinal damper
• New damper board

2
Beam measurements with transverse damper on show
oscillation of beam becomes smallerquickly
with a big injection error lifetime of very
high beam intensity (3.3e13) at 8 GeV are
improved ? before the shutdown in last October
After the shutdown, there was a test to check the
transverse damper operation -gt it was not
working (vertical or horizontal directions) -gt
now damper for the vertical direction (y) works
using spare amplifiers -gt the old board seems not
to work for the horizontal direction (x) -gt new
board will be installed in the near future -gt new
transverse amplifiers will arrive soon
3
Change in bunch phase with Long. Damping on
? Five bunches bunches 1,3,4 are damped
bunch 2 is left alone bunch 5 is
anti-damped
Mountainrange plot of RWM signal for 4 booster
turns for about 7000 turns after injection into
Main Injector.
Bunches Green, red, cyan, purple and yellow
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Effect of long. Damping on different Beam types
Data from damper system
Data from RWM at 150GeV
transition
Damper off
Damper on

• Bunch length is shorter and beam is more stable
  with damper on
• ? Also measured Long. e is smaller

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Anti-damped
Rest bunches are damped
The big lurches in phase at turns 6000-7000 are
at the start of acceleration. Transition is at
turn 13000 and the bunches come out of
transition with big oscillations.
Damper off
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Transition crossing on normal stacking cycle(29)
Transition crossing with damper
(Kiyomi Koba)
First five bunches of stacking cycle
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Transition crossing with damper
Transition crossing on normal stacking cycle(29)
Last five bunches of stacking cycle
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Bunch train before extraction with damper
(Kiyomi Koba)
Data from RWCM for all 84 bunches
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Reduced bunch length with the long. Damper on 29
Bunch length without damper
Bunch length with damper
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Bunch length of stacking cycle beam at extraction
0.8 1.8 ns without damper 0.8 ns (? 10) with
damper working -gt bunch length of stacking cycle
affects production on the anti-proton
target -gt the range of the bunch length is much
smaller with the damper on
Currently, longitudinal damper is operating on
coalescing cycle (beam goes to Tevatron)
stacking cycle
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Development of new damper boards (January)

• Trans. and long. Dampers can work simultaneously
• A lot more RAMs and a bigger chip to implement
  new features ? 10 times more RAMs than the old
  one more logic elements ? using
  approximately half of RAMs for damping
• The data-taking rates of ADC and DAC are twice as
  fast
• Firmware can be downloaded to boards through
  ethernet
• Can be used for other purpose (barrier stacking,
  Booster LLRF)

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Development of new damper boards (continued)
Status within a month new board will be
installed 1. Hardware noise measurement, input
output test of ADC DAC are
done
? 4 out of 5
boards are fine one of them
is used for pbar debunching operation 2.
Firmware all subcircuits are programmed and
tested except subcircuits for
damping process FIFO DAQ ? ? testing for
damping process will be done next 2 weeks 3.
Displays through ACNET are done but need to be
tested
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A new board is cabled up in MI 60 last Feb.

• Revolution marker, MDAT and TCLK input output
  signals are checked for general operation of the
  board
• Parameters for the new board are checked for the
  firmware codes -gt the manual is almost finalized
• Variables of ACNET are tested (still in progress)
  -gt all the ACNET
  variables exist for all 5 boards
• New ACNET pages are generated for the new damper
  boards
• Commission new boards without disconneting the
  old board
• Final transverse amplifies will arrive soon
  -gt first one this
  week the remaining three by the end of April

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New damper parameter pages on ACNET
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(No Transcript)
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The manual for new damper boards (still need to
be modified)
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Variables on ACNET
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JAVA display for the damper is partially working