Undulator K-Parameter Measurements at LCLS J. Welch, SLAC National Accelerator Laboratory
[email protected] Josh Stein 10.31.07 Beam Loss Monitor Control LCLS Undulator Systems Beam Loss...
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[email protected] v Josh Stein 10.31. 07 Beam Loss Monitor Control LCLS Undulator Systems Beam Loss Monitor Control Interface Josh Stein LCLS Undulator Controls CAM/TL Bill Berg ANL/APS Diagnostics Group Arturo Alarcon SLAC Controls
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Transcript of [email protected] Josh Stein 10.31.07 Beam Loss Monitor Control LCLS Undulator Systems Beam Loss...
Josh Stein10.31.07
Beam Loss Monitor Control
LCLS Undulator SystemsBeam Loss Monitor Control Interface
Josh Stein LCLS Undulator Controls CAM/TL
Bill Berg ANL/APS Diagnostics Group
Arturo Alarcon SLAC Controls
Josh Stein10.31.07
Beam Loss Monitor Control
Undulator Protection Requirements
Inputs to inhibit the e-beamPrimary protection from a number of Beam Loss Monitors (BLMs) along the undulatorSecondary protection from control system monitoring of
BPM orbitMagnet power supply statusMagnet mover status
Long-term monitoring of the radiation doseDosimeters attached to the magnets
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Beam Loss Monitor Control
BLM Specification
A single BLM will be placed in each of the gaps between undulator modules.
Design is to maximize the sensitivity of the monitorLocated as close as possible to the beam axis as the vacuum chamber allows
Choose a sensitive Cerenkov medium coupled to a high gain photomultiplier tube
The detector will not be segmented to provide transverse position information of the losses
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Beam Loss Monitor Control
BLM Rolls Out with Undulator Magnet
The BLM is mounted to tightly surround the vacuum pipe near the beam finder wire
It is on a linear slide so that it can be moved off the beam when the undulator magnet is rolled out
An detachable arm makes the BLM and magnet roll out together
The BLM will automatically be less sensitive to beam loss when the undulator is in the out position
The BLM can be manually inserted on the beam pipe for special calibration procedures
Josh Stein10.31.07
Beam Loss Monitor Control
BLM reliability and self test
Each loss monitor is equipped with a LED that flashes between beam pulses.
Provides a pre-beam test of the BLM system before beam is sent through the undulator
Provides a stay-alive signal for the control system to monitor the BLM system during operation
Josh Stein10.31.07
Beam Loss Monitor Control
BLM dynamic range
For simplicity and cost the BLM will be optimized for maximum sensitivity And allowed to saturate the signal if a large loss occurs
The trip threshold is still exceeded if the device saturates so the MPS will still trip and protect the undulatorMonitoring of the loss signal to integrate the dose received by the undulator will not be valid if the device saturatesHowever, if large losses are anticipated such as when the beam finder wires are inserted, the gain of the PMT will be reduced to prevent saturation.
Josh Stein10.31.07
Beam Loss Monitor Control
BLM Signal Monitoring
The BLM has a fast, dedicated link to the MPS to shutoff the beam within 1 pulseThe local MPS link node chassis also has a ‘slow’ network connection to the control system via channel access
Allows monitoring of the BLM level at any timeReads back and controls the PMT voltageControls the LED test pulseControls the threshold set point for MPS trips
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Beam Loss Monitor Control
BLM Controls Architecture pk
The BLM PMT interfaces to the MPS link node chassis.
The IO board of the MPS link node chassis provides the ADC & DAC for the PMT.
A cable interface box is the treaty point between the MPS and the undulator BLM.
There are 5 link node chasses serving up to 8 BLMs along the undulator. (expandable to 16 channels)
Josh Stein10.31.07
Beam Loss Monitor Control
Beam Loss Monitors with Link Nodes
Use Link Node tosupport analog I/O IndustryPack modules
provide analog readouts to control system
set threshold levels
control HV power supplies
control LED Pulser
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Beam Loss Monitor Control
Undulator Hardware
LINKNODE
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35
LINKNODE
LINKNODE
LINKNODE
LINKNODE
SparesSpares
Josh Stein10.31.07
Beam Loss Monitor Control
Beam Loss Monitor - Undulator Hardware (m. brown)
In Undulator Hall
Long Haul Cables
Power
ControlSystem
MPSNetwork
HVPS CONTROL
LED PULSER AMPL.
( IP DAC )
HVPS READ BACK
( IP ADC )
CUSTOM
GATED INTEGRATOR
( IP )
LED PULSER BOARD
HV POWER SUPPLY
PMT&
BASE
LED
FIBER
ColdFire
FPGA
I/O
TRIGGER
119 MHz + FIDUCIAL
*
LINK NODE CHASSIS
AC POWER
UndulatorBeam Loss
Detector(8)
888
Timing Fanout
Timing Distribution
*
MPSLINK
*Fiber
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Beam Loss Monitor Control
Future expansion
The link node chassis can handle more than the present number of installed BLMs
During commissioning a long fiber BLM will also be tested
It is compatible with the link node chassis controls
Josh Stein10.31.07
Beam Loss Monitor Control
BLM System Support Focus Topics1. Assignment of Eric Norum to controls design oversight and testing.
2. Funding of beam based prototyping and test program.
3. Group Leaders to significantly step up direct involvement in system oversight, program implementation, and schedule tracking (controls: n. arnold, diag: g. decker, lcls: g. pile, ops/analysis: m. borland).
4. Active participation in simulations and simulation priority from slac.
5. Implementation of upstream profile monitor (halo or at min. cal foil).
6. Adequate analysis and shielding of upstream beam dump.
7. Develop long term collaboration plan for the pursuit of determining magnet damage mechanisms and thresholds via empirical methods.
8. Determine need and priority of BLM signal integration (diagnostic).
Josh Stein10.31.07
Beam Loss Monitor Control
Summary
Undulator magnets protection is critical for machine commissioning period.
Schedule for development of the blm program is very aggressive and Funding is limited.
System design and fabrication must go in parallel with simulation and testing program.
Consider Minimum requirements for first level implementation. Taking advantage of existing mps infrastructure.
BLM system is now defined as a component of the mps with an upgrade path to a diagnostic (low gain detection).
36 distributed channels (2 static devices) capable of single pulse detection and rate limiting reaction.
Detectors track with undulator position with detach option for manual operation.
Calibration plan and hardware is vital to proper system operation (Threshold detection with empirically derived levels).
Josh Stein10.31.07
Beam Loss Monitor Control
Proposed PIC / BLM Timing
PIC TIMINGFIDUCIAL
or Trigger near Fiducial time
INTEGRATIONWINDOW = 2.5 mSec
2.5 mSec
BLM TIMING
FIDUCIAL FIDUCIAL
INTEGRATIONWINDOW = 20uSec
1020 uSecDELAY = 1020 uSec
DELAY = 0
The proposed trigger timing for the BLM and PIC Systems will be derived from 119MHz with Fiducial ( i .e.nomial Fido signal )
FIDUCIAL119 MHz
The MPS Link chassis will receive this signal on a trigger input and will output a trigger for the BLM or PIC IP Modules .
FIDUCIALor Trigger near Fiducial time
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Beam Loss Monitor Control
Link Node Block Diagram
ColdfireComputer
( RTEMS /EPICS )
FPGAVitrex -4
XC4VFX20
Interface Transceivers
MPS Fiber Link
SFP
Gereral-Purpose TTL I /O
Output Ifc Bd(Opto -Isolators )
MPS Link Node – Functional Block Diagram
Ethernet
MPS Devices
Fault
Inputs(96)
Mitigation Device Outputs
(8)
Industry PackInterface
Industry PackModule 1
SignalCond Board
Industry PackModule 2
SignalCond Board
GPIO for status , ctrl , etc .( Unused Trigger I /O signals)
Industry PackModule 3
SignalCond Board
Industry PackModule 4
SignalCond Board
Input Ifc Bd 6(Opto -Isolators )
Input Ifc Bd 1(Opto -Isolators )
Trigger I /O
USB Ifc
4
4
Trigger I /O can be configured as
needed
From EVR
To other devices
PC Laptop
Local Debug Port
Node Address Switches
Josh Stein10.31.07
Beam Loss Monitor Control
( )( )1
1122
cos
sinsin
βω
φφγ
−×
×−×=
A
rr
System Roll
Josh Stein10.31.07
Beam Loss Monitor Control
Introduction• Physics Requirements Document: Heinz-Dieter Nuhn 9-28-07
(prd: 1.4-005-r0 undulator beam loss monitor).
• Scope Reduction: diagnostic to mps detector. • Purpose and Requirements.
• Budget: M&S 500k (325 detector ctls/mps 175).
• Schedule: (design: n-m, test: f-m, fab: m-j, inst: july).
• Organization: 4 groups.
• Group Definition: controls, detector, simulation, test & calibration.
• Design Highlights and System overview (detectors: dynamic 33, static: 2, r&d fiber:1).
• Detector design details and focus topics.
• Funds are limited and efforts need to be focused to minimize costs (h-dn).
• Simulation of losses and damage in the undulator will proceed in parallel with the present effort (pk).
Josh Stein10.31.07
Beam Loss Monitor Control
BLM Purpose h-dn
The BLM will be used for two purposes:
A: Inhibit bunches following an “above-threshold” radiation event.
B: Keep track of the accumulated exposure of the magnets in each undulator.
Purpose A is of highest priority. It will be integrated into the Machine Protection System (MPS) and requires only limited dynamic range from the detectors.
Purpose B is also desirable for understanding long-term magnet damage in combination with the undulator exchange program but requires a large dynamic range for the radiation detector (order 106 ) and much more sophisticated diagnostics hard and software.
The BLM will be used for two purposes:
A: Inhibit bunches following an “above-threshold” radiation event.
B: Keep track of the accumulated exposure of the magnets in each undulator.
Purpose A is of highest priority. It will be integrated into the Machine Protection System (MPS) and requires only limited dynamic range from the detectors.
Purpose B is also desirable for understanding long-term magnet damage in combination with the undulator exchange program but requires a large dynamic range for the radiation detector (order 106 ) and much more sophisticated diagnostics hard and software.
Josh Stein10.31.07
Beam Loss Monitor Control
BLM requirements pk
Primary function of the BLM is to indicate to the MPS if losses exceed preset thresholds.
MPS processor will rate limit the beam according to which threshold was exceeded and what the current beam rate is.
The thresholds will be empirically determined by inserting a thin obstruction upstream of the undulator.
Simulation of losses and damage in the undulator will proceed in parallel with the present effort.
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Beam Loss Monitor Control
Draft Budget Breakdown
500k M&S Total325k Detector Development25k Interface Box150k Control and MPS integration
25k link node chassis 25k long haul cables 50k davis bacon labor 15k ctl modules and signal conditioning electronics 25k clean power distribution 10k racks
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Beam Loss Monitor Control
Draft scheduledetector nov dec jan feb march april may june july aug septdetector design prototype x xprototype fabrication x x xprototype testing (beam) x xdetector design lock xdetector fabrication x xdetector assembly xship to slac xinstallation x x
interface boxprototype xtesting x xdesign lock x
custom control/sc boardsckt brd prototype design x xckt brd prototype fabrication x xcontrol/sc prototype test xcontrol/sc proto test (beam) x xdesign lock xfabrication x xsystem build xinstallation x x
mps and infrastructurecable plant (utility bldg) xcable plant (tunnel) xrack power xtunnel racks xmps system x x
calibration planstart xfinish x
simulation (ongoing effort)
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Beam Loss Monitor Control
LCLS MPS Beam Loss Monitor
System Engineer: W. Berg
Cost Account Manager: G. Pile Technical Manager: D. Walters
Scientific advisor: P. Krejcik* FEL Physics: H. Nuhn* Scientific advisor: B. Yang FEL Physics: P. Emma*
Controls/MPS Group Lead (ctls) : J. Stein Lead (mps): A. Alacron*
Detector Group
Lead: W. Berg
Simulations and analysis Group
Lead: M. White
Testing and Calibration Group
Lead: B. Yang
M. Brown *R. Diviero E. NorumS. Norum *B. LairdJ. Dusatko*
A. BrillL. ErwinR. KeithleyJ. Morgan
J. DoolingB. Yang
W. BergJ. Bailey J. DoolingL. MoogE. NorumM. White
* Slac employee
Josh Stein10.31.07
Beam Loss Monitor Control
MPS Beam Loss Monitor Group Functions
Controls Group: J stein, A. Alacron
Develop BLM control and mps system:Interface Box and Control
PMT Signal conditioning
Control and user displays
Detector Group: W. Berg
Develop Detector and Interface.
Simulations and Analysis Group: M. White
Provide collaborative blm simulation support and test analysis.
Test and Calibration Group: B. Yang
Provide beam based hardware testing programs and calibration plan.
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Beam Loss Monitor Control
Design Highlights33 distributed detectors (one preceding each undulator segment), two static units (up and downstream of undulator hall).
One additional channel reserved for r&d fiber based system.
Dynamic detector, 100mm stroke (tracks undulator) with undulator position detection (in/out) for adjusting mps threshold levels.
Large area sensor (full horizontal width of top and bottom magnet blocks).
Manual insertion option via detachable arm for special calibration and monitoring.
Fiber out for low gain upgrade (full integration and dyn range diagnostic) system expandable to 80 channels.
Calibrated using upstream reference foil (initial use of simulation based levels).
MPS threshold detection and beam rate limiting.
Heart beat led pulser for system validation before each pulse up to full rep rate (pseudo calibration).
Remote sensitivity adjust (dynamic range) by epics controlled pmt dc power supply (600-1200Vdc out).
Single pulse detection, level measurement, and mps action at max rep rate via dedicated mps link.
Radiation hard detector (materials and electronics).
Monitoring live single shot signal levels (dedicated) and recording of integrated values to one second.
