Topup Operation on Diamond
Mark Heron
16/10/2008
Topup Operation on Diamond to
EPICS Meeting 2008
1
Decay Mode Operation
• Electrons are injected on periodic basis
– Determined by Life Time
– During injection Shutters are Closed
• Part of PSS SR Operate
– IDs may be opened, but are put under Control Room control
Mark Heron
16/10/2008
Topup Operation on Diamond to
EPICS Meeting 2008
2
Thermal Induced Disturbances
Mark Heron
16/10/2008
Topup Operation on Diamond to
EPICS Meeting 2008
3
What is Topup?
• Electrons are injected into the Storage on a periodic
basis
– Injection period determined by stability requirement of
stored beam and photon beam
• 2mins for Diamond
– During initial injection Shutters are Closed but once a
stored beam is established Topup injection can proceed
with Shutters open
• Part of PSS in Topup mode
– IDs are closed and under beamline control
Mark Heron
16/10/2008
Topup Operation on Diamond to
EPICS Meeting 2008
4
Advantages of Topup
• Higher average brightness
– Higher average current
– Constant flux on sample
• Improved stability
– Constant heat load
• Machine components
• Beamline optics
– Beam current dependence of BPMs
• Flexible operation
– Lifetime less important
• Smaller ID gaps
• Lower coupling
– Hybrid mode with different life times in MB and SB
Mark Heron
16/10/2008
Topup Operation on Diamond to
EPICS Meeting 2008
5
What does it mean for beamlines ?
• Safety
– Concern that the injection process could fail and the
injected electrons would end up in the beamline
– Beamline shielding is designed to contain Photons, not
electrons or by-products ( Neutrons ) produced by
electron interactions
• Influence of injection process during topup on
photon beam stability.
– Imperfections in the injection process disturb the stored
beam
– Injected beam has to damp down on to the orbit of the
stored beam
Mark Heron
16/10/2008
Topup Operation on Diamond to
EPICS Meeting 2008
6
Safety Tracking Studies
• Carried out tracking studies to
establish that each Beam-line is
safe for top-up.
• This analysis:
1. Electrons travelling forwards
from straight section cannot
pass down beam-line
2. Electrons travelling backwards
from beam-line cannot pass
through to straight section
3. Electrons travelling in either
direction do not have same
trajectory at any intermediate
point
Mark Heron
16/10/2008
Topup Operation on Diamond to
EPICS Meeting 2008
7
Safety tracking failing Dipole
•Dipole bending magnets
steer electrons away from
beam-line opening
•If bending magnets fail,
electrons go straight forward
(following path of x-rays)
Phase-space borders overlap if B<23%
Stored beam lost if B<~99%
Beam-line I02 safe for this type of error
ESLS-XV 22nd Nov 2007
Plans for Top-Up at Diamond
Ian Martin
B = 100%
75%
50%
25%
0%
Safety Interlocks Implemented
•
To exclude the possibility of transmission of
injected electrons into an optics hutch, allowing all
possible magnet errors (lattice independence),
requires
1. Stored beam interlock, to exclude single dipole failure
upstream of a beamline
2. Energy interlock, to exclude difference in energy of >
5% between injected and stored beams
Mark Heron
16/10/2008
Topup Operation on Diamond to
EPICS Meeting 2008
9
Health Physics Interlock
• BL Radiation Monitors are being upgraded
to include sensitivity to Neutrons. (
Produced when electrons collide with
matter)
• Currently interlock is on Dose Rate greater
4uSv/hr
• Add a new Interlock on the the Integrated
Dose over 4hours at a level of 2uSv.
– Gives sensitivity to lower ongoing losses
• The 4 hour integrator is integral to monitor
– Will be resent by a 4 Reset signal
produced every 4 hours by the Timing
system.
– Resets will be synchronised to start of shift.
• HP Interlocks are part of the PSS
– On M/C prevent interjection
– On BL close Shutter
Mark Heron
16/10/2008
Topup Operation on Diamond to
EPICS Meeting 2008
10
Fill Pattern Measurement
• Actual fill pattern measured using PicoHarp time-correlated
single photon counting system.
• Average fill pattern over period between top-up cycles.
• Fill pattern is used to determine the buckets to be filled, but
number of buckets is determined from overall beam current,
measured by DCCT
Mark Heron
16/10/2008
Topup Operation on Diamond to
EPICS Meeting 2008
11
Topup Process
Establish stored beam (shutters closed)
Close IDs / open shutters
Switch to top-up mode
Test injector (single bunch into BTS stop)
Gun off / switch on BTS dipole
Warm up storage ring pulsed magnets
Identify low-charge bunches from fill pattern
Inject until above stored current threshold
Turn off injector / BTS dipole
2 min delay between injections
Mark Heron
16/10/2008
Topup Operation on Diamond to
EPICS Meeting 2008
12
Topup application
• Application written in Python
– uses the Qt GUI
– matplotlib for graphs.
• Allows parameters of top-up to be
varied.
• Provides interface for failure
diagnosis.
• Allows display of top-up statistics.
Mark Heron
16/10/2008
Topup Operation on Diamond to
EPICS Meeting 2008
13
Topup application: Interlocks
• Not part of Safety
• Intention is:
– to prevent top-up from being started in
inappropriate circumstances,
– to stop top-up before a PSS trip
occurs so that the machine falls back
to decay mode operation and beam is
not lost.
• When an error is detected, top-up
process stops as cleanly as
possible and sets top-up state to
“Failed”.
• Interlocks includes:
– Transfer efficiency B to BTS, Transfer
efficiency BTS to SR Stored Beam
current, Beam lifetime, Charges in
individual SR buckets, shots to correct
buck, valves open, and BST correct
optics
Mark Heron
16/10/2008
Topup Operation on Diamond to
EPICS Meeting 2008
14
Topup Application: Statistics Generated
• Statistics are generated to
detect any drift in top-up
performance.
• Generate averages for:
–
–
–
–
Last 10 cycles
Last hour
Last 6 hours
Last 24 hours
• For
– Overall, LTB, BTS, and SR
Mark Heron
16/10/2008
Topup Operation on Diamond to
EPICS Meeting 2008
15
Topup Test
• Total current stable at 128.4mA to 0.1%
Pk-pk ~ 0.2mA
σ ~ 0.06mA
Mark Heron
16/10/2008
Topup Operation on Diamond to
EPICS Meeting 2008
16
Imperfections in the Injection Process
V
coll
K1
K2
16 (nominal)
Septum
8.5°
850 mm
K4
K3
13.7 (nominal)
850 mm
H
coll
8.3
22 (nominal)
850 mm
850 mm
160
1870mm
190
160
190
2560
900
740
233.60
(min 206.84, max
260.37)
456.40
(max 483.16, min
429.63)
8300
• At injection the Stored Beam is bumped toward the Septum
magnet by a half sine wave pulse lasting ~ 6usec.
• Realised use kickers (K1, K2, K3 and K4 )
– If perfectly, matched then there is no disturbance to Stored Beam.
Mark Heron
16/10/2008
Topup Operation on Diamond to
EPICS Meeting 2008
17
Real Kicker Waveforms
• Kicker Pulse are ~6usec and 3900A
• There are differences in the PSUs and magnets (asymmetries) and in the
coating of the vessels.
Mark Heron
16/10/2008
Topup Operation on Diamond to
EPICS Meeting 2008
18
Real Injection Disturbance
• Stored beam is disturbed
– ± 250 um horizontally,
– ± 150 um vertically
– Lasts 10 to 12 msec
Mark Heron
16/10/2008
Topup Operation on Diamond to
EPICS Meeting 2008
19
100 ms
SR Inj
SR Inj
SR Inj
Gating Signals
100 ms
NO INJECTION !!!
100 ms
TOP-UP-ON
10 ms
TOP-UP-OFF
T-delay
T-width
CH-0
Short
GATE
CH-1
CH-2
Short
GATE
Long
Short
GATE
GATE
Storage Ring Clock
TOP-UP Mode (for 3 injecting cycles)
•
Top up every 2mins
– Top-up requires around 10 shots into the SR
– 200msec between each shot
– Each shot disturbing the stored beam for around 10 to 12 msec. Overall injection
period for a top-up cycle would last for around 2 seconds every 2 mins.
•
•
At present we are not able to prevent the beam disturbance
Gating signals will be available to stop motion and or the detector, when the
beam is disturbed.
– Short Gate shot by shot
– Long Gate over the whole injection period.
•
Software and hardware gating signals are provided
Mark Heron
16/10/2008
Topup Operation on Diamond to
EPICS Meeting 2008
20
Thanks
• C. Bailey, R. Bartolini, P. Bonner, C. Christou, Y.
Chernousko, T. Dobbing, A. Gonias, N. Hammond, I. Martin,
C. Ide, V. Kempson, E. Longhi, G. Rehm, B. Singh, S.
Singleton, R. P. Walker, M Wilson
• H. Nishimura, D. Robin, A. Terebilo
• And many more…
Mark Heron
16/10/2008
Topup Operation on Diamond to
EPICS Meeting 2008
21
Decoded Gate Signals
Name of
Signal
TOP-UPON (event)
TOP-UPOFF (event)
SHORT
GATE
LONG
GATE
Reference
event
TOP-UP-ON
SR CLK
TOP-UP-ON
and
TOP-UP-OFF
no
RF CLK
no
Mark Heron
16/10/2008
Type of
EVR output
PULSE
DELAY
>>>
GATE
>>>
DISTR.
BUS
Restored RF
Delay
range
0 – 100ms
=0
Width range
8ns - 200ms
200ms x (N-1)
+ 110ms
=0
=0
fixed 936 ns
=0
fixed 1ns
Topup Operation on Diamond to
EPICS Meeting 2008
Comments
Fixed Event, 100ms before
each SR Injection cycle
Fixed Event, 10ms after the
last SR Injection cycle
User defined pulse
delay/width
Fixed position of the signal,
defined on system level
22
Gating Signal Interface
TTL
TTL
TTL
PECL PECL
+ RF Out -
+ Out 1 -
+ Out 0 -
IN
OUT4
VMEEVR
RF
ENET
OUT3 OUT2
OUT1 OUT0
CRATE
PECL
0
1
Channel 0
SHORT GATE
Channel 1
LONG GATE
Channel 2
SR CLK
Channel 3
Channel 4
Channel 5
7
7
6
6
5
4
3
2
5
1
0
2
3
4
Channel 7
RF CLK
Channel 6
Timing
Interface Panel
+3.3V
TTL
Mark Heron
16/10/2008
TTL
TTL
TTL
TTL
TTL
PECL
LVDS
TTL
PECL
LVDS
TTL
Topup Operation on Diamond to
EPICS Meeting 2008
PECL
23
Possible Beamline EVR Application
VME-EVR Control Panel
Pulse / Gate / Data
Event
Type of Data
Delay / Width (us)
Enable - Disable
CHANNEL 0
PULSE
TOP-UP-ON
80000 / 30000
Enable
Disable
CHANNEL 1
GATE
TOP-UP-ON
TOP-UP-OFF
0/0
Enable
Disable
CHANNEL 2
DATA
SR-CLK
0/0
Enable
Disable
CHANNEL 3
PULSE
TOP-UP-ON
xxxxxx / xxxxxx
Enable
Disable
CHANNEL 4
GATE
TOP-UP-ON
TOP-UP-OFF
0/0
Enable
Disable
CHANNEL 5
DATA
SR-CLK
0/0
Enable
Disable
CHANNEL 6
PULSE
TOP-UP-ON
xxxxxx / xxxxxx
Enable
Disable
Mark Heron
16/10/2008
Topup Operation on Diamond to
EPICS Meeting 2008
24
Gating Signal Levels
• Ch.0 – Ch.4.
– TTL signals on BNC
• Ch.5 and Ch.6
– TTL levels (coax LEMO)
– PECL levels (2-pin LEMO)
– LVDS levels (2-pin LEMO).
• Ch. 7
– Restored RF-CLK PECL ( 2-pin LEMO)
• Some channels have fixed names (Short Gate, Long gate,
SR CLK and RF CLK)
Mark Heron
16/10/2008
Topup Operation on Diamond to
EPICS Meeting 2008
25
References
• TDI-CTRL-REQ-009 Beamline Top-up gating requirements
summarise requirement for beamlines, I02,I03,I04, I06, I15,
I16, I18, I22, I24 and B16.
– Now out of date.
• TDI-CTRL-TI-SPEC-BL-001 Details the interface for gating
signal on beamlines.
Mark Heron
16/10/2008
Topup Operation on Diamond to
EPICS Meeting 2008
26
Topup Super Cycle
Realization of Bucket List
ON: Linac,
OFF: Gun, BR-Inj/Extr, SR-Inj, BTS Dipole
ON-OFF Transit: BTS Dipole
Pause
BTS Dipole Current
BR-Extr Test (B cycles)
Pre-heating (A cycles)
BTS Dipole “ON transition” (C cycles)
Top-Up Operation (D cycles)
Pause (~ 5 min)
Preparation time (A+B+C cycles)
up to A = 10 - 20
up to B = 5-10 (?)
up to 5 min
up to D = 10 - 20
up to C = 5-10 (?)
T-ZERO
0
1
2
3
4
5
6
7
8
0
1
2
3
4
5
6
0
1
2
3
4
5
6
1
2
3
4
5
6
7
8
0
1
2
3
4
T-ZERO
T-ZERO
T-ZERO
T-ZERO
T-ZERO
BR-HWTRG
BR-HWTRG
BR-HWTRG
BR-HWTRG
BR-HWTRG
LINACHBT
LINACHBT
LINACHBT
LINACHBT
LINACHBT
BR-HBT
BR-HBT
BR-HBT
BR-HBT
BR-PREEXTR
LINACPRE
BR-PREEXTR
BR-PREEXTR
5
6
7
8
9
10
11
LINACPRE
BR-PREEXTR
SR-PREINJ
~ 50000 us
~ 50000 us
~ 50000 us
~ 50000 us
~ 58160 us
~ 58160 us
~ 58160 us
~ 58160 us
~ 149000 us
~ 149000 us
~ 149000 us
~ 149000 us
DELAY SET ZONES FOR:
- Gun Triggering Pulses
- BR-PRE-EXTR event
~ 50000 us
~ 58160 us
(in correspondence with Bucket List)
Mark Heron
16/10/2008
Topup Operation on Diamond to
EPICS Meeting 2008
27
TOP-UP-PRE
>
Gun, Linac, BR-Inj/Extr,
SR-Inj, BTS Dipole
BTS-DPL-OFF
IF OK
ON:
TOP-UP-OFF
Checking “chargeefficiency” factor
BR-Inj/Extr Pre-heating
ON: Linac, BR-Inj/Extr
OFF: Gun, SR-Inj
OFF-ON Transit: BTS Dipole
BTS Dipole transition
to ON state
TOP-UP-ON
TOP-UP-PRE
ON: Gun, Linac, BR-Inj/Extr
OFF: BTS Dipole, SR-Inj
BTS-DPL-ON
Top-Up Supercycle (Ver. 1)
ON: Linac, BR-Inj/Extr
OFF: Gun, BTS Dipole, SR-Inj