Transcript New RF System Commissioning Experience

Linac Coherent Light Source (LCLS)
Low Level RF System
New RF System Commissioning
Experience
April 16, 2007
April 16, 2007
LCLS LLRF FAC
Ron Akre, Dayle Kotturi
[email protected], [email protected]
Safety
Hazards in the LLRF system
RF 1kW at 120Hz at 5uS = 0.6 Watts average,
2 Watt average amps at 2856MHz,
60W average amps at 476MHz
Hazards – RF Burns
Mitigation – Avoid contact with center conductor of energized
connectors. All employees working with LLRF systems are
required to have the proper training.
110VAC Connector
Hazards - Shock
Mitigation - Don’t touch conductors when plugging into outlet.
All chassis are inspected by UL trained inspector (EEIP).
April 16, 2007
LCLS LLRF FAC
Ron Akre, Dayle Kotturi
[email protected], [email protected]
LCLS Layout
P. Emma
April 16, 2007
LCLS LLRF FAC
Ron Akre, Dayle Kotturi
[email protected], [email protected]
Scope of Work for Injector Turn-on 1
Linac Sector 0 RF Upgrade
All 3 RF Chassis completed and Installed
Control Module (IQPAU) needs modifications
Sector 20 RF distribution system Phase and Amplitude Controllers (PAC) - Operational
Phase and Amplitude Detectors (PAD) - Operational
Phased Locked Oscillator – Use SPPS unit for Turn On
LO Generator - Operational
Multiplier – 476MHz to 2856MHz - Operational
4 distribution chassis - Operational
Laser Phase Measurement – Needs some signal processing
X-Band Reference – Chassis built, require testing and installation
LLRF Control and Monitor System
1 kW Solid State S-Band Amplifiers – 5 units
PADs – 6 Klystron units in Fabrication
PADs – Gun, L0A, L0B, L1S – Operational : Tcav, L1X in test
PACs – Gun, L0A, L0B, L1S –Operational : TCav, L1X in test
Beam Phase Cavity
PAD in test
Pill box cavity with 2 probes and 4 tuners – Complete
April 16, 2007
LCLS LLRF FAC
Ron Akre, Dayle Kotturi
[email protected], [email protected]
Scope of Work for Injector Turn-on 2
LLRF VME control system
Local feedback loops on RF phase and amplitude
RF Gun Cell loop tested in lab at 360 Hz and in operation at 10 Hz
L1-S loop tested in lab at 360 Hz and in operation at 30 Hz
L0-A and L0-B loops tested in lab at 100 Hz
Gun Tune temperature loop testing in progress
Event system and timing triggers configured for accelerate and
standby
External interfaces
Beam-synchronous acquisition
LEM, SCP Correlation plots
Channel Archiver – active for all installed channels
Alarm Handler – initial layout done by J. Rock. Alarm limits TBD
Global beam-based longitudinal feedback on L0-B and L1-S untested
April 16, 2007
LCLS LLRF FAC
Ron Akre, Dayle Kotturi
[email protected], [email protected]
SLAC Linac RF – New Control
MDL 476MHz
Next Sector
1mW
1W
6X
2856MHz
Existing
Phase
Reference
Line
3
SubBooster
Sub Drive Line
The new control system will tie in
to the IPA Chassis with 1kW of
drive power available. Reference
will be from the existing phase
reference line or the injector new
RF reference
To Next
Klystron
I
3kW
1
Phase &
Amplitude
Detector
Klystron
SLED
200MW
April 16, 2007
LCLS LLRF FAC
-45dB
Accelerator
1kW Amp
2856MHz
Q
4
IPA
High Power
Phase Shifter
Attenuator
20mW
Existing
System
LO
2 RF
IQ Modulator
I and Q will be controlled with a
16bit DAC running at 102MHz.
Waveforms to the DAC will be set
in an FPGA through a
microcontroller running EPICS on
RTEMS.
Ron Akre, Dayle Kotturi
[email protected], [email protected]
Processing RF Stations
Gun – About 1 Week to Full Power
L0A – About 2 Weeks to Full Power
Most stations were and still are gassy by the klystron.
April 16, 2007
LCLS LLRF FAC
Ron Akre, Dayle Kotturi
[email protected], [email protected]
Processing RF Stations
L0B – About 2 weeks to Full Power
April 16, 2007
LCLS LLRF FAC
L1S – Easy 1 Week to Full Power
Ron Akre, Dayle Kotturi
[email protected], [email protected]
Gun High Power RF Pulse Shaped by PAC
L0A and L0B look similar
Amplitude Waveform flat to +-2%
Phase Waveform flat to +-2 Degrees
Pulse width of 1.2uS and >600nS of waveguide eliminates klystron power change due to
reflected power and need for circulator.
April 16, 2007
LCLS LLRF FAC
Ron Akre, Dayle Kotturi
[email protected], [email protected]
L1S High Power RF SLED Pulse Shaped by PAC
SLED Amplitude Waveform
April 16, 2007
LCLS LLRF FAC
Phase Waveform flat to +-2 Degrees
Over fill time of structure
Ron Akre, Dayle Kotturi
[email protected], [email protected]
Operational Units
S-Band
Reference
System
Laser SPAC
Gun PAC
L0-A PAC
L0-B PAC
L1-S PAC
April 16, 2007
LCLS LLRF FAC
Ron Akre, Dayle Kotturi
[email protected], [email protected]
PADs – Ready for Commissioning
April 16, 2007
LCLS LLRF FAC
Ron Akre, Dayle Kotturi
[email protected], [email protected]
Injector/L1 Units Remaining to Commission
TCav PAC
Gun (done 4/12/07), L0-A, L0-B, L1-S, TCav
PADs
Klystron PADs
Sector 0 IQPAU
X-Band System
VME based Feedbacks (Gun Cell Done)
Diagnostic data analysis
April 16, 2007
LCLS LLRF FAC
Ron Akre, Dayle Kotturi
[email protected], [email protected]
To Follow
PAC software – more analysis in FPGA
PAD software – evaluate speed
Second network – to send waveforms out while
running
Switch to final network configuration putting
embedded IOCs on private network
Switch access to waveforms to use CA gateway
VME – quantify CPU usage as each station is
added
April 16, 2007
LCLS LLRF FAC
Ron Akre, Dayle Kotturi
[email protected], [email protected]