Booster Cogging Upgrades ig Drennan, Kiyomi Seiya, Alex Wal
Jan 13, 2016
Booster Cogging Upgrades
Craig Drennan, Kiyomi Seiya, Alex Waller
RF cogging to momentum coggingcurrent cogging-RF cogging
momentum cogging
hardware requirements
Replace cogging board with new boardswitch to MFC board
status
Why do we need cogging?
Gap for the extraction kicker
Booster is going to extract 12 pulses every 15Hz for the Nova operation.Booster notch position supposes to synchronize to the MI injection.
MI 1 revolution
1st pulse2nd pulse
Time
Move notch creation earlier
Intensity
B field
1st pulse 2nd pulse
Notch @ 400msec @ 7msec
The notch was created at 7msec for the 2-12th pulse.Creating the notch at lower energy can reduce beam loss in the Booster.
35000000
40000000
45000000
50000000
55000000
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0 0.005 0.01 0.015 0.02 0.025 0.03 0.035
rf f
req
uen
cy[H
z]
B[T
]
time[sec]
0
500000
1000000
1500000
2000000
0 0.005 0.01 0.015 0.02 0.025 0.03 0.035
MIBooster
Inte
gra
ted
rf
bu
cket
[b
uck
ets
]
time [sec]
Bucket difference between Booster and MI
MI inj. freq. : 52811400Hz
The bending field in the Booster, injection energy, timing, rf feedback …..are changing from pulse to pulse and bucket position at extraction is not constant.
-80
-60
-40
-20
0
20
40
60
80
0 0.005 0.01 0.015 0.02 0.025 0.03 0.035
B=a0-a1*cos(2*pi*freq_cyc+del_t)
dt=+0.1msecdt=+0.2msecdt=+0.5msecdt=-0.1msecdt=-0.2msecdt=-0.5msec
[bu
cket
s]
time[sec]
-80
-60
-40
-20
0
20
40
60
80
0 0.005 0.01 0.015 0.02 0.025 0.03 0.035
B=a0-a1*cos(2*pi*freq_cyc*(1+del_f))
freq+0.01%freq+0.02%freq+0.05%freq-0.01%freq-0.02%freq-0.05%
[bu
cket
s]
time[sec]
Current cogging – RF cogging – (1)
Notch @ 7msec
Final bucket position
-Predicts final bucket position by measuring Gradient1, 2. -Sends RPOS offset which is required for the frequency changes.
The revolution frequency difference between reference cycle and cycle with B field error.
1
2
Current cogging – RF cogging – (2)
Transition energyRPOS offset
Final bucket position+/- 10 buckets
Fixed with RPOS feedback
Changed by dipole correctorDipole corrector: 0.009[T-m] @ 24.4[A]
B field error ~1% can be compensated.
Momentum cogging
B+dB
Keeps the orbit centered and saves aperture. Has two feedback loops for frequency and RPOS .
(Assuming 10[A] change )
Dfrev with RF cogging and Momentum cogging
-5
0
5
10
15
20
-5
0
5
10
15
20
0 0.005 0.01 0.015 0.02 0.025 0.03 0.035
RF cogging
Momentum cogging
[bu
cket
s/m
m/m
sec] [b
uck
ets/A/m
sec]
time[sec]
Counts:ΔC[turn]
diff_rev_ freq
ΔCn-1[turn], ΔCn[turn]
Calculates gain for RPOs offsets.
Calculates gain for corrector
current.
DSPFPGAB dot
MI rev marker
Booster rev m
DAC Radial offset
DAC
Dipole correctors RPOS feed back
Cogging board
Momentum cogging (before 7msec)
RF cogging (after 7msec)
Notch pulse
Control for the dipole corrector offseet
Current curve 1 short-H-1
H-short01ΣDAC
Need cable, amplifier and timing for all 48 corrector.
C473
PS
CoggingMFC
DAC
Amp/msec
Switching to new boardCurrent Cogging board MFC board
DSP
SHARC
FPGA
ALTERA
AD/LLRF group has been developing this board for the last 10 years.
It is similar to the current cogging board. (VXI based ALTERA FPGA)
Current cogging board has one spare. Some parts are no longer available.
Spec:32 * 12-bit, 65MS/S ADC input channels including 2 DC coupled channels 1 * 14-bit105MS/S ADC input channel 4 * 14-bit 260 MS/S DAC channels configurable as AC or DC coupled 1 * 8 output clock divider chip with a 1.6 GHz max external clock input 1 * External Aux clock input (LVCMOS) to FPGA and/or DAC 2 * Front panel TTL trigger inputs
Multi cavity Field Control (MFC) Module‐
Booster LLRF VXI crate
1 2 3 4 5 6
1: slot 0
2: beam power
3: Digital freq. reference
4: Para Phase
5: Cogging
6: pulse to Cogging
Resource Manager Booster LLRF VXI cratefrequency curve -Logical address (SC)Beam power (SC)Para phase (SC)RF Cogging (SC)new cogging with MFC board (DC)
FPGA and DSP codessetup environments on PC.
header, library, compiler…..
Slot 0 cardnew Motorola compiler
Communication between slot 0 card and DSPold: slot 0 shared memory DSPnew: slot 0 ------------------- DSP
Status of the new board
RF cogging on the new board. (before shutdown)
Setup offset control for dipole corrector. (during shutdown)
Add momentum cogging. (during shutdown)
Beam studies and simulations. (on going)
Future Plan