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PEP II Transverse Feedback SystemRon Akre
William Colocho
Anatoly Krasnykh
Vojtech Pacak
Dmitry Teytelman
Uli Wienands
MAC January 18, 2006
PEP II Transverse Feedback System
The PEP TFB system takes the vector sum of 2 BPMs, delays the signal by the remainder of 1 turn and delivers a kick to the beam the next time around. Two stripline kickers, one for X and one for Y, are used.
PEP II TFB Highlights for Run 5
New Moly Kicker Electrodes and larger, 7/16 DIN, connectors allow higher current running in LER – LER has run for 3 days at 3 Amps.
Added phase shifters to HER receivers to independently phase X and Y
Removal of orbit offset electronics increases gain in receiver chassis.
Replace HER BPM Attenuators with higher power units
The new data acquisition system and analysis software is running and collecting Gigabytes of data.
New LBNL 2 Tap Filter / Delay installed in LER Y since August and in HER for a few weeks in December
G-proto in LER Y for a week in September and LER X for a few weeks in December
PEP II Transverse Feedback SystemRun 5 Resolved Hardware Problems
• 18 Log Entries associated with hardware problems– 16 Power Amp Problems
• 14 transistors
• 5 regulator boards
– 1 High Power Filter Blown: LER Y-– 1 Failed BPM Attenuators: LER 2C
PEP II TFB Receiver
Orbit offset correction are done by changing beam orbit to minimize dX and dY signals. Receiver chassis have been modified to eliminate orbit offset adjustment and give more gain.
Manual phase shifters added to phase HER X and HER Y independently
PEP II TFB Digital Delays• Lawrence Berkeley Laboratory
Phase 1: 2 - 12 bit ADC to clock data into FPGA at 238MHzTwo tap filter with 1 turn delay plus variable delay238MHz DAC with differential outputProgrammable through COM port.Completed – Installed in LER Y August 2005
Phase 2: Record 16MS, 70mS, of data to external memoryThree trigger modes
Grow/ Damp MeasurementsFault File DataSoftware trigger to capture data during running
On board EPICS control with Ethernet for programmingFinal Software being completed
Principal Investigators: Walter Barry and John ByrdAlex Chin, Larry Doolittle, Alex Ratti, Jonah Weber
PEP II TFB Digital Delays
New Digital Delays – 2 tap filter and diagnostics are being developed by LBNL
ADC0
ADC1
DDRSDRAM
HybridSplitter DAC
PowerSplitter
Attenuator
FrequencyDoubler
TranformerCoupling
PECLGate
Tuning Cables
FPGA
Xilinx ML300 Power I/O Board
PowerConnector I/O Connectors
2 TTL Inputs
MonitorSignal
Clock Input119 MHz Sine
ControlSignal
Red = 119 MHz Clock
Blue = 238 MHz Clock
SLAC TFB CPU Board
Ethernet
Compact FlashCard
SystemACE
LocalNetwork
JTAG Configuration Port
2 NIM Inputs
Jonah Weber LBNL
PEP II TFB Power Amplifiers and Filters
Power Amplifiers
Reliability of the power amplifiers still remain a large concern. Each of the 8 amplifiers has 8 power transistors summed for the output. During this run 5 so far we have lost about 14 output power transistors.
Largest reliability concern
During the past down time all the amplifiers have been tested and repaired
The orbit offsets and phase transients cause the amplifiers to run close to saturation. The new digital delay two tap filters eliminate orbit offsets and greatly reduce power requirements in the amplifers.
Filters
So far only 1 filter failure – the new 7/16 DIN connector in LER Y- did not fail, but internal LC components did.
PEP II TFB Kickers Uli Wienands, Anatoly Krasnykh, Artem Kulikov, Jay Langton, Many Others
New kickers with moly electrodes, redesigned coax to stripline transition, and 7/16 DIN connectors have been installed in LER.
PEP II TFB Data Acquisition System
GAGE 82G PCI 8bit 2GHz 2 Channel Digitizer 16Mb Memory
2 Cards 4 Channels – HER X and Y and LER X and Y
3rd card is on order to monitor other signals
GAGE card is clocked at 238MHz bunch frequency
Inputs are from vector sum out of Analog Signal Processor for X and Y
Programmable triggers: Inputs from HER / LER Fault, HER / LER Injection, HER / LER Software. Output trigger for grow/damp measurements. PEP TFB TRIGGER CHASSIS
PEP II TFB Data Acquisition System
Files are stored in central NFS space
Compiled MatLab routines for analysis of data sets are run from a GUI
ANALOG SIGNAL PROCESSOR
dXdY
dXdY
Network Connection
238MHzClock
Trigger
GAGEPCI Scope Card2GSPS 8bitMS Windows XP
476MHz CLKTurns CLKSCP TrigFault TrigInjection Trig
X+X-
Y+Y-
DIGITALDELAY1 TURNY
dY
dX
MonitorCalibrated Cable Lengths
dX2dY2
D
dX1dY1
BPM1
BPM2 #2
ABCDB
C
B
ABCD
ARECEIVER
#1C
D
RECEIVERA
LO
AD
S
X+X-
Y+Y-
PREAMPS
X K
ICK
ER
POWER AMPS
BEA
M
To Y KICKER
FILTERS
80pS Step10nS Delays
dX1dY1
dX2dY2
DIGITALDELAY1 TURNX
Trigger Chassis
PEP II TFB Data Acquisition SystemAnalysis Software
Display All Data
Display Selected Data
Plot RMS FFT
Plot Modes
Plot Mode Phase
Plot Mode Growth Fit
High Resolution FFT
High Resolution FFT 2
Plot Spectrogram
W. Colocho, V. Pacak
Compiled MatLab Software Run from GUI
12-08-05 21:17 ~2200mA LER
LER CURRENT
X
Y
X Y
Grow Damp Measurements August 16, 2005Mode -1
Grow Damp Measurements August 16, 2005
0.74 1/mS 0.96 1/mS
0.69 1/mS 0.63 1/mS
Grow Damp Measurements August 16, 2005
Growth Rates vs. Beam CurrentsMode -1
0
0.2
0.4
0.6
0.8
1
1.2
0 1000 2000 3000
Beam Current mA
Gro
wth
Rat
e 1/
mS
Grow Damp Measurements August 16, 2005
PEP II TFB Concerns for Higher Current Running
Feedback Gain and Output Power
Plan to do grow / damp measurements in both HER and LER.
LBNL two tap filters have shown large increases in system gain, postponing the need for larger power amplifiers. The new delays require less rack space if larger power amps are required.
Filters are currently working well – 1 failures with new connector
Only 1 filter, LER Y-, has 7/16DIN connector – the rest use N connectors
(This same filter is the only one which failed during this run)
Kickers
New Moly electrodes in LER, they have handled up to 3 amps and are expected to work to 4.5 amps.
7/16DIN Feed-through connectors replaced SC, and eliminate SC to N adapters.
As the bunch length shortens higher frequencies of beam induced power will need to be directed to proper loads.
Measurements of beam induced power from kicker to amplifiers need to be done.
PEP II TFB Near Term Run 5 Tasks
• Set up collaboration with LBNL to assist with measurements
• Measure power reflected to amplifier from kicker – Especially LER Y-
• Grow / damp measurements both planes of both rings• Transfer function measurements in both rings• Install 2 tap filters in both planes of both rings• Install 3rd GaGe card to monitor 2 additional channels