William Berg1.24.08
Beam Loss Monitor
LCLS Undulator SystemsBeam Loss Monitor
William Berg ANL/APS Diagnostics Group
William Berg1.24.08
Beam Loss Monitor
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.
• ANL Budget: M&S (325k detector, ctls interface box 100k).
• Detector Schedule: (design: nov-dec,drawings: dec-feb,pro/fab/assy: feb-jun,del: july, inst: aug-sep).
• 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).
William Berg1.24.08
Beam Loss Monitor
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. BLM 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 of 106 ) and much more sophisticated diagnostics hard and software.
William Berg1.24.08
Beam Loss Monitor
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.*Beam Current threshold determination?
• 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.
William Berg1.24.08
Beam Loss Monitor
ANL Draft BLM Budget
• 425k M&S Total:
• 325k Detector Development
• detectors
• mounting and slide systems
• cables and fiber
• 100k Controls Interface Box
William Berg1.24.08
Beam Loss Monitor
Draft schedule
Detector nov dec jan feb march april may june july aug sept
design x x
component drawings x x
assembly drawing x x
procurements x x
design lock x
fabrication x x x
assembly x x
ship to slac x
installation x x
William Berg1.24.08
Beam Loss Monitor
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: J. Dooling
Testing and Calibration Group
Lead: B. Yang
M. Brown *R. Diviero J. Dusatko *S. Norum *A. Pietryla
A. BrillL. ErwinR. KeithleyJ. Morgan
L. EmeryM. Santana *J. Vollaire *B. Yang
W. BergJ. Bailey J. DoolingL. Moog
* Slac employee
William Berg1.24.08
Beam Loss Monitor
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 MPS Integration and User Displays.
• Detector Group: W. Berg• Develop Detector and Machine Integration.
• Simulations and Analysis Group: J. Dooling• Provide collaborative blm simulation support and test analysis.
• Test and Calibration Group: B. Yang• Provide beam based hardware testing programs and calibration plan.
William Berg1.24.08
Beam Loss Monitor
System Design Highlights
• 33 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.
• MPS threshold detection and beam rate limiting.
• Single pulse detection and mps action up to max 120Hz beam rep rate via dedicated mps link.
• Monitoring of real time shot to shot signal levels and record integrated values up to one second.
• 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 (600-1200V).
• Calibrated using upstream reference foil (initial use cal will be determined from simulation studies).
William Berg1.24.08
Beam Loss Monitor
Detector Design Highlights
• Cerenkov Radiation Based (x-ray beam noise immunity).
• Employs PMT for high sensitivity to beam losses.
• Dynamic detector (tracks with undulator) 100mm stroke. Undulator position (in/out) detection will be used to set the corresponding mps threshold levels.
• Manual static insertion option via detachable arm for special calibration and monitoring.
• Large area sensor (coverage of the full horizontal width of the top and bottom magnet blocks).
• Fiber Out for low gain upgrade (full integration and dyn range diagnostic), control system expandable to 80 channels.
• Radiation hard components (materials and electronics).
William Berg1.24.08
Beam Loss Monitor
Vendor List
Radiator Substrate water jet and final polish (lap and flame) (quartz)- VA Optical
Radiator AlSi coating – Eddy Company
Radiator Material - Corning
PMT and Magnetic Shield - Hamamatsu
Connectors: SMA Fiber Feed through) -Thor Labs
High Voltage Feed through - Kings
SMB Signal Fed through - AMP
Fiber Optic Cable (heartbeat) Fiber (fused silica) - Stocker Yale
Fiber Optics Cable, UV Grade – Coastal Connections
Signal Cable – Belden
Body Fabrication- M1, High Tech, AJR Industries
Miscellaneous Hardware (fasteners, o-rings, flex coupling, spanner wrench) – McMaster-Carr
Linear Bearing Assembly – IKO International
Spherical Bearing – Aurora Bearing
William Berg1.24.08
Beam Loss Monitor
BLM System Support Focus Topics
• Funding of beam based prototyping and test program.
• Implementation of upstream calibration foil (alt. profile monitor/halo).
• BFW prototype tolerance verification (system tolerance in LTT)
William Berg1.24.08
Beam Loss Monitor
BLM Summary• Undulator magnets protection is critical for machine commissioning period.
• BLM system is now defined as a component of the mps (descope) with an upgrade path to a diagnostic (low gain detector).
• Calibration plan and hardware is vital to proper system operation (threshold detection will use empirically derived levels).
• Schedule for development of the blm program is very aggressive and funding is limited.
William Berg1.24.08
Beam Loss Monitor
Detector Summary• Building a detector based on cerenkov radiation and PMT detection.
• 36 distributed channels (2 static devices) capable of single pulse detection (up to full rep rate) with rate limiting reaction.
• Detectors dynamically track with undulator position with manual detach option to remain in a fully inserted static position.
• Adjustable PMT sensitivity with remotely controlled high voltage power supply.
• Keep alive system test (led pulser) before each beam pulse.
• All Vendors have been identified, Quotes in progress, Drawing set being reviewed.
• Installation does not require access into the vacuum system or removal of other components.
William Berg1.24.08
Beam Loss Monitor
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).9. BFW prototype verification (system tolerance LTT)
William Berg1.24.08
Beam Loss Monitor
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 detector). 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 will
use empirically derived levels). Quotes in progress Drawing set being reviewed
William Berg1.24.08
Beam Loss Monitor
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 detector interface box (pmt, led pulser, sig con?) 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 from 8 to16 channels).
William Berg1.24.08
Beam Loss Monitor
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
William Berg1.24.08
Beam Loss Monitor
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
William Berg1.24.08
Beam Loss Monitor
Segment Design Layout m. brown
MPS Link
Node
William Berg1.24.08
Beam Loss Monitor
Locking Pin Detail (moves with undulator)
Spherical Bearing
Flex Joint
William Berg1.24.08
Beam Loss Monitor
Beam Loss Monitor - Undulator Hardware (m. brown)
In Undulator Hall
Long Haul Cables
Power
ControlSystem
MPSNetwork
HV
PS
CO
NT
RO
LLE
D P
ULS
ER
AM
PL.
( IP
DA
C )
HV
PS
RE
AD
BA
CK
( IP
AD
C )
CU
ST
OM
GA
TE
D IN
TE
GR
AT
OR
( IP
)
LED PULSER BOARD
HV POWER SUPPLY
PMT&
BASE
LE
D
FIBER
ColdFire
FPGA
I/O
TRIGGER
119MHz + FIDUCIAL
*
LINK NODE CHASSIS
AC POWER
UndulatorBeam Loss
Detector(8)
888
Timing Fanout
Timing Distribution
*
MPSLINK
*Fiber
William Berg1.24.08
Beam Loss Monitor
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
William Berg1.24.08
Beam Loss Monitor
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
William Berg1.24.08
Beam Loss Monitor
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
William Berg1.24.08
Beam Loss Monitor
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
William Berg1.24.08
Beam Loss Monitor
BLM Specification
A single BLM will be placed in each of the gaps between undulator modules.Design is to maximize the sensitivity of the monitor
Located as close as possible to the beam axis as the vacuum chamber allowsChoose a sensitive Cerenkov medium coupled to a high gain photomultiplier tubeThe detector will not be segmented to provide transverse position information of the losses
William Berg1.24.08
Beam Loss Monitor
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
William Berg1.24.08
Beam Loss Monitor
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.
William Berg1.24.08
Beam Loss Monitor
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
William Berg1.24.08
Beam Loss Monitor
BLM Controls Architecture
The BLM PMT interfaces to the MPS link node chassisThe IO board of the MPS link node chassis provides the ADC & DAC for the PMTA cable interface box is the treaty point between the MPS and the undulator BLMThere are 5 (? verify this number) link node chasses serving up to 8 BLMs along the undulator (a diagram would help here)
William Berg1.24.08
Beam Loss Monitor
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