Status of the PS TFB
J. Belleman, E. Benedetto, F. Caspers, D. Glenat, R. Louwerse,
M. Martini, E. Métral, V. Rossi, J. Sladen, J.M. Nonglaton
Acknowledgments:
R. Steerenberg, S. Gilardoni
1. Hardware Overview
2. Machine results
3. To be done
Alfred Blas
APC 30/1/2009
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PS TFB
Block diagram
Green boxes represent devices to be completed
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PS TFB
Clock distribution PS CB
Hardware
setup
Power + electronics 355-R-017
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Kickers + transformers PS SS 97
APC 30/1/2009
Water distribution 355-R-017
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PS TFB
Pick-up amplifiers
J. Belleman
BW: 20 kHz – 40 MHz
80 dB dynamic range (compatible with ions)
Remotely programmable gain
Located in the ring below concrete slab
Alfred Blas
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PS TFB
Alfred Blas
DSPU hardware
APC 30/1/2009
V. Rossi
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PS TFB
DSPU firmware
Green boxes represent functions to be completed
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PS TFB
Clock generation
1 GHz DDS
Receives the frequency program
from the PS central building and
outputs the 160*Frev (< 80 MHz).
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J. Sladen
Clock Generator
Transforms 10 MHz into 1 GHz
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PS TFB
Pre-Amplifier
Fast Clipping of the output signal
0 and 180o outputs
Programmable gain
TFM setup
Local / Remote control
Interface with the PLC control
Alfred Blas
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PS TFB
Power Amplifier
R. Louwerse
[2.5 kHz – 25 MHz],
3kW – 2ms, 800W – CW
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PS TFB
Impedance matching transformers
Input impedance: 50 Ω
Output impedance: 100 Ω
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R. Louwerse
[ 2kHz – 40 MHz]
APC 30/1/2009
3 kW
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PS TFB
Alfred Blas
Kicker
APC 30/1/2009
F. Caspers, V. Bretin
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PS TFB
Alfred Blas
Kicker
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PS TFB
Power loads
100Ω to 50Ω resistive transition
[ DC – 190 MHz] 1.6 kW CW
50 Ω / 30 dB Attenuator
[ DC – 1GHz] 1 kW CW
Alfred Blas
APC 30/1/2009
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PS TFB
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PLC Power Control
APC 30/1/2009
D. Glenat
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PS TFB
Operation
display
J. M. Nonglaton
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PS TFB
Results: Automatic delay
•Resolution=0.4ns
•Measurement time: 22 us
•Maximum jitter : 260 ps
•Precision requirement:
1.1 ns for 10o error at 25 MHz
Alfred Blas
APC 30/1/2009
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PS TFB
Machine Results
Auto Dly + Hilbert
The proper functioning of the automatic delay has been tested during
an MD on MDPS (22/09/08) with a copy of the SFTPRO beam.
The beam transfer function was measured on the 3.5 GeV plateau and
on the 14 GeV plateau.
BTF of a Q+q betatron line
Alfred Blas
If the phase response of all betatron lines can be superimposed, the
delay is correct.
The parameters of the automatic delay were set at 3.5 GeV for a
proper phase response and the measurements made again at 14 GeV
proved that the circuit behaved as expected.
The measurements made another day at 1.4 GeV gave the same
positive results.
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PS TFB
Alfred Blas
Results: Notch Filter
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PS TFB
Results: Hilbert Filter
M= 3 Hilbert
Without Notch Filter – set value = 45o
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With Notch Filter – set value = 45o
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PS TFB
Results: Hilbert Filter
M= 1 Hilbert
Without Notch Filter – set value = 45o
Alfred Blas
With Notch Filter – set value = 45o
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PS TFB
Sensitivity to Q measurement
With the PU in SS98 and the kicker in SS97, the ideal betatron phase lag within the TFB path can be expressed
as follow (qH,V Є [0 , 0.5]):
ΔφB-TFB = -111.6o + (536.4o * q) in the case of no delay for the dephasing (2 PUs!)
ΔφB-TFB = -111.6o + (896.4o * q) in the case of 1TREV delay for the dephasing (m=1 Hilbert)
ΔφB-TFB = -111.6o + (1616.4o * q) in the case of 3TREV delay for the dephasing (m=3 Hilbert)
 9o phase error for an error in q of 0.01 with the m=1 Hilbert
( <=> 4.5 kHz error in the FFT)
One measurement
made on LHC25.
11/11/08
The Q measurements
are supposed to have a
precision of 100ppm
Unfortunately during the
tests we had a jitter from
cycle to cycle
The rf clock of the Q
measurement doesn’t
take into account the
loop errors of the RFLL.
Is this the explanation?
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APC 30/1/2009
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PS TFB
30mm p-p initial H error
Results
MDPS 1.4 GeV flat cycle with no Chromaticity and no coupling
23/10/08
PSB MD1 beam 55.1010 p injected (3 turns in R3)
Injection error obtained by setting PI.KFA45 to 270 kV instead of 300 kV
Inj. error Damping: 20mm/ms @ 1.4 GeV (21mm/ms required for the most
demanding case: Pilot beam εn = 0.8μm)
500 μs/div
Power system used for controlled blow-up (slow extraction) and Q
measurement
From M. Martini
APC 26/5/2005
Alfred Blas
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PS TFB
Results
30mm p-p initial H error
500 μs/div
Zoom
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top = h position
APC 30/1/2009
bottom = kick
2μs/div
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PS TFB
Results MD 11/11/2008
With coupling – No TFB
E. Metral
Without coupling – No TFB
•LHC25 injection plateau at 1.4 GeV with linear H/V
coupling (Iskew =-0.3)
•Without coupling (Iskew = +0.3)
•See logbook for more details (11/11/08)
•Last plot taken from a good shot; not always the case
Without coupling – With TFB
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(The Betatron phase was set to an empirical fixed value!)
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PS TFB
Results
MD 11/12/2008
•Q measurement
Without coupling – No TFB
Only the H plane is excited
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PS TFB
Conclusion
The MDs on the machine show that the PSTFB fulfills the expected requirements:





Kick efficiency
Automatic delay
Hilbert filter
Remote control of the DSPU and of the Power system
Usage of the power system for the Q measurements and controlled blow-up
Improvements for 2009:
Hardware
 2 fully loaded DSPU modules instead of the single beta version.
 2nd input on the DSPU with a serial delay for the 2nd PU. ( -> lower sensitivity to Q value)
 3rd and 4th inputs on the DSPU for the PU SUM signals (normalization of the Delta signal)
 DSPU input impedance varies with the input attenuation (52 -> 72Ω)
 Install a driver for a better compatibility with the Q measurement excitation
Firmware
 Notch filter could be modified for a more suitable phase response
 Q-to-Hilbert-phase LUT should be adapted to take into account the phase errors of the Hilbert (with respect to the
command) together with the response of the Notch.
Software
 Q (h and V) measured along the cycle (0.01 precision) and value sent to a GFAS (PA.GSTFBH and PA.GSTFBV)
 PU control knob to be created (Automatic gain as a function of peak beam intensity ?)
Other
 Q measurement (rev clock used for the sampling of the beam signal precise enough ?)
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