LCLS Undulator Systems
Beam Loss Monitor Control Interface
Josh Stein
Bill Berg
Arturo Alarcon
10.31.07
Beam Loss Monitor Control
LCLS Undulator Controls CAM/TL
ANL/APS Diagnostics Group
SLAC Controls
Josh Stein
Stein@aps.anl.gov
Undulator Protection Requirements
Inputs to inhibit the e-beam
Primary protection from a number of Beam Loss
Monitors (BLMs) along the undulator
Secondary protection from control system
monitoring of
BPM orbit
Magnet power supply status
Magnet mover status
Long-term monitoring of the radiation dose
Dosimeters attached to the magnets
10.31.07
Beam Loss Monitor Control
Josh Stein
Stein@aps.anl.gov
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 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
10.31.07
Beam Loss Monitor Control
Josh Stein
Stein@aps.anl.gov
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
10.31.07
Beam Loss Monitor Control
Josh Stein
Stein@aps.anl.gov
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
10.31.07
Beam Loss Monitor Control
Josh Stein
Stein@aps.anl.gov
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 undulator
Monitoring of the loss signal to integrate the dose
received by the undulator will not be valid if the device
saturates
However, 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.
10.31.07
Beam Loss Monitor Control
Josh Stein
Stein@aps.anl.gov
BLM Signal Monitoring
The BLM has a fast, dedicated link to the
MPS to shutoff the beam within 1 pulse
The 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 time
Reads back and controls the PMT voltage
Controls the LED test pulse
Controls the threshold set point for MPS trips
10.31.07
Beam Loss Monitor Control
Josh Stein
Stein@aps.anl.gov
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)
10.31.07
Beam Loss Monitor Control
Josh Stein
Stein@aps.anl.gov
Beam Loss Monitors with Link Nodes
Use Link Node to
support analog I/O IndustryPack modules
provide analog readouts to control system
set threshold levels
control HV power supplies
control LED Pulser
10.31.07
Beam Loss Monitor Control
Josh Stein
Stein@aps.anl.gov
Undulator Hardware
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
Spares
Spares
LINK
NODE
10.31.07
Beam Loss Monitor Control
LINK
NODE
LINK
NODE
LINK
NODE
LINK
NODE
Josh Stein
Stein@aps.anl.gov
Beam Loss Monitors using Link Nodes
10.31.07
Beam Loss Monitor Control
Josh Stein
Stein@aps.anl.gov
Beam Loss Monitor - Undulator Hardware
Undulator
Beam Loss
Detector
(8)
FIBER
LED
PMT
&
BASE
HV POWER
SUPPLY
(m. brown)
8
8
8
LED PULSER BOARD
TRIGGER
CUSTOM
GATED INTEGRATOR
( IP )
HVPS CONTROL
LED PULSER AMPL.
( IP DAC )
HVPS READ BACK
( IP ADC )
LINK NODE
CHASSIS
FPGA
Power
ColdFire
I/O
*
In Undulator Hall
MPS
LINK
119MHz +
FIDUCIAL
Timing
Fanout
*
Long Haul Cables
AC POWER
Control
System
MPS
Network
Timing
Distribution
*Fiber
10.31.07
Beam Loss Monitor Control
Josh Stein
Stein@aps.anl.gov
BLM Interconnect Diagram
10.31.07
Beam Loss Monitor Control
m. brown
Josh Stein
Stein@aps.anl.gov
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
10.31.07
Beam Loss Monitor Control
Josh Stein
Stein@aps.anl.gov
BLM System Support Focus Topics
1.
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).
10.31.07
Beam Loss Monitor Control
Josh Stein
Stein@aps.anl.gov
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).
10.31.07
Beam Loss Monitor Control
Josh Stein
Stein@aps.anl.gov
End of Presentation
10.31.07
Beam Loss Monitor Control
Josh Stein
Stein@aps.anl.gov
Supporting slides
10.31.07
Beam Loss Monitor Control
Josh Stein
Stein@aps.anl.gov
Segment Design Layout
10.31.07
Beam Loss Monitor Control
m. brown
Josh Stein
Stein@aps.anl.gov
Interface Box Location
10.31.07
Beam Loss Monitor Control
Josh Stein
Stein@aps.anl.gov
Plan View of Short Drift
10.31.07
Beam Loss Monitor Control
Josh Stein
Stein@aps.anl.gov
BFW Pump Out Port Relocation
10.31.07
Beam Loss Monitor Control
Josh Stein
Stein@aps.anl.gov
Removable Pin for Manual Insertion
10.31.07
Beam Loss Monitor Control
Josh Stein
Stein@aps.anl.gov
Undulator Retracted Position
10.31.07
Beam Loss Monitor Control
Josh Stein
Stein@aps.anl.gov
Undulator Inserted Position
10.31.07
Beam Loss Monitor Control
Josh Stein
Stein@aps.anl.gov
Rendering of Detector
10.31.07
Beam Loss Monitor Control
Josh Stein
Stein@aps.anl.gov
Cross Section of BLM Detector
10.31.07
Beam Loss Monitor Control
Josh Stein
Stein@aps.anl.gov
Proposed PMT Device (420nm)
10.31.07
Beam Loss Monitor Control
Josh Stein
Stein@aps.anl.gov
Proposed PIC / BLM Timing
The proposed trigger timing for the BLM and PIC Systems will be derived from 119MHz with
Fiducial ( i.e.nomial Fido signal )
119 MHz
FIDUCIAL
The MPS Link chassis will receive this signal on a trigger input and will output a trigger for the
BLM or PIC IP Modules.
PIC TIMING
FIDUCIAL
or Trigger near
Fiducial time
FIDUCIAL
or Trigger near
Fiducial time
INTEGRATION
WINDOW = 2.5 mSec
DELAY = 0
2.5 mSec
BLM TIMING
FIDUCIAL
FIDUCIAL
INTEGRATION
WINDOW = 20uSec
DELAY = 1020 uSec
10.31.07
Beam Loss Monitor Control
1020 uSec
Josh Stein
Stein@aps.anl.gov
Link Node Block Diagram
MPS Fiber Link
Input Ifc Bd 1
PC
Laptop
USB Ifc
SFP
(Opto-Isolators)
Fault
Inputs
(96)
Local Debug Port
Interface
Transceivers
FPGA
Vitrex-4
XC4VFX20
Coldfire
Computer
Ethernet
(RTEMS/EPICS)
Input Ifc Bd 6
Output Ifc Bd
(Opto-Isolators)
Node
Address
Switches
From
EVR
Gereral-Purpose
TTL I/O
Mitigation
Device
Outputs
(8)
GPIO for status, ctrl, etc.
(Unused Trigger I/O signals)
4
Trigger I/O
To other
devices
MPS
Devices
(Opto-Isolators)
Industry Pack
Module 1
Signal
Cond Board
Industry Pack
Module 2
Signal
Cond Board
Industry Pack
Module 3
Signal
Cond Board
Industry Pack
Module 4
Signal
Cond Board
4
Trigger I/O can be
configured as
needed
Industry Pack
Interface
MPS Link Node – Functional Block Diagram
10.31.07
Beam Loss Monitor Control
Josh Stein
Stein@aps.anl.gov
MPS Overview
10.31.07
Beam Loss Monitor Control
(m. brown)
Josh Stein
Stein@aps.anl.gov
System Roll

10.31.07
Beam Loss Monitor Control
r2  sin 2  r1  sin 1 
A  cos  1 
Josh Stein
Stein@aps.anl.gov
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).
10.31.07
Beam Loss Monitor Control
Josh Stein
Stein@aps.anl.gov
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.
10.31.07
Beam Loss Monitor Control
Josh Stein
Stein@aps.anl.gov
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.
10.31.07
Beam Loss Monitor Control
Josh Stein
Stein@aps.anl.gov
Draft Budget Breakdown
500k M&S Total
325k Detector Development
25k Interface Box
150k 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
10.31.07
Beam Loss Monitor Control
Josh Stein
Stein@aps.anl.gov
Draft schedule
detector
detector design prototype
prototype fabrication
prototype testing (beam)
detector design lock
detector fabrication
detector assembly
ship to slac
installation
nov
x
dec
x
x
x
x
x
march
april
may
x
x
june
july
aug
sept
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
mps and infrastructure
cable plant (utility bldg)
cable plant (tunnel)
rack power
tunnel racks
mps system
calibration plan
start
finish
feb
x
interface box
prototype
testing
design lock
custom control/sc boards
ckt brd prototype design
ckt brd prototype fabrication
control/sc prototype test
control/sc proto test (beam)
design lock
fabrication
system build
installation
jan
x
x
x
x
x
x
simulation (ongoing effort)
10.31.07
Beam Loss Monitor Control
Josh Stein
Stein@aps.anl.gov
LCLS MPS Beam Loss Monitor
System Engineer: W. Berg
Cost Account Manager: G. Pile
Scientific advisor: P. Krejcik*
Scientific advisor: B. Yang
Controls/MPS Group
Lead (ctls) : J. Stein
Lead (mps): A. Alacron*
M. Brown *
R. Diviero
E. Norum
S. Norum *
B. Laird
J. Dusatko*
Detector Group
Technical Manager: D. Walters
FEL Physics: H. Nuhn*
FEL Physics: P. Emma*
Simulations and
analysis Group
Testing and Calibration
Group
Lead: W. Berg
Lead: M. White
A. Brill
L. Erwin
R. Keithley
J. Morgan
J. Dooling
B. Yang
Lead: B. Yang
W. Berg
J. Bailey
J. Dooling
L. Moog
E. Norum
M. White
* Slac employee
10.31.07
Beam Loss Monitor Control
Josh Stein
Stein@aps.anl.gov
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.
10.31.07
Beam Loss Monitor Control
Josh Stein
Stein@aps.anl.gov
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.
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.
10.31.07
Beam Loss Monitor Control
Josh Stein
Stein@aps.anl.gov