Beam Loss Monitors
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Transcript Beam Loss Monitors
Beam Loss Monitors
B. Dehning
29.11.2005
LHC Radiation Day, B. Dehning
1
Some remarks
Capacitors test with high dose
Damage threshold on collimator
Transient losses: Alfredo,
Steady state losses: xxx
SC link transient losses value?
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LHC Radiation Fields
Radiation spectra are very similar
Radiation levels in [cm-2 Gy-1]
beampipe with cryostat
6 x 1010 n > 100 keV
4 x 109 h > 20 MeV
2 x 109 h > 100 MeV
beampipe
4 x 109 n > 100 keV
8 x 108 h > 20 MeV
5 x 108 h > 100 MeV
Annual dose
C. Fynbo, LHC seminar 22/11/01
1-2 Gy alongside magnets, 10-20 Gy in inter magnet gaps
35-150 Gy in dispersion suppressors, 9 kGy in cleaning sections
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Radiation in the LHC
J. Vollaire et al. "Calculation of Water
Activation for the LHC, Proc. AccApp05
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Parameterisation of a complex radiation
field
h > 20 MeV
Single Events
h > 100 KeV
EM cascade
nuclear cascade
Displacement
SEU counter
Dose
radiation damage
semiconductors
PIN Diodes
Radfet
Radiation Monitor
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Radiation Sensors per monitor
Dose, dose rate
Hadron flux, hadron fluence
Tyndall Radfets – 2 different types at a maximum of 1 rad/bit
TC554001AF-70 SRAM – 4 x 4 Mbit gives 1 SEU per 1 106 n > 20 MeV
1 MeV eq. neutron fluence
SIEMENS BPW34FS – 3 diodes at maximum of 5 109 neutrons/bit (1 MeV)
Inaccuracy
Resolution
Range
Dose [Gy]
±10 %
0.01
200
Dose Rate [Gy/hr]
±10 %
0.01
50
Neutron fluence
[n/cm2]
±15 %
5 109
1 1013
Hadron fluence [h/cm2]
±15 %
1 106
1 1012
Hadron flux [h/cm2.s]
±15 %
1 106
2.3 1011
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SEU counter design specifics
Comparison per “byte”, reference pattern “0”
3 V or 5 V operation (3 V most sensitive)
Cycle time variable (to deal with frequency effects in SRAM)
read, write, compare
215 nsec – 1 ms
total scan (16 Mbit SRAM)
450 ms – 2100 ms
2 x Triple redundant counting registers
Readout speed 3 counters via fieldbus over 2.5 km
(6 actions : LSB1 FREEZE - MSB1 – LSB2 - MSB2– LSB3 - MSB3)
4 kHz
- 1 monitor
100 Hz - 32 monitors
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Induced Activity Monitors
Example of dose rate decrease monitoring
Beam on
Typical graph used to plan interventions
(Work and dose planning)
Beam off
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Induced Activity Monitors
Main characteristics
PE hull (4mm) /
inside graphite
coated
Measure the ambient dose equivalent and ambient dose equivalent rate
in photon fields (beam off);
Plastic ionisation chamber (3 litres, 1 atm. Air-filled);
Manufactured by PTW Freiburg;
Performances :
15.8
cm
Measuring range : 5 µSv/h to 500 mSv/h
Energy range : 50 keV to 7 MeV
Measuring time : from 1 to 3600 s
Typical value 60 s
HV = -1 kV
Active volume
Anode: PE /
graphite coated
21.5
cm
28.5
cm
Connector to
cathode
Connector to
anode
Connector plug for power
supply and signal outlet
[2] Reference H. Vincke et al.
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Induced Activity Monitors
Very low current over long distances
HIGH RADIATION FIELDS during BEAM ON REMOTE ELECTRONICS
Measure current ranging from 100 fA up to 10 nA at a distance up to 750 m
Tunnel or
Experimental
areas
Protected
Area
Average length = 200 m (min =50 m, max = 750 m)
Remote
readout
Electronics
Detector
CERN *SPA6 cable (CERN design)
*SPA6 cable registered by CERN Technology Transfer Group
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Measurement of dose at a copper target intercepting beam (120 GeV/c)
The fluence spectra close to the beam loss points in the LHC will be similar to
those present at the CERF experiment
RPL1
1
0.1
0.01
RPL2
1
0.1
0.01
2
1E-3
1E-4
1E-5
charged hadrons
neutrons
photons
- +
e e
1E-6
1E-7
1E-8
1E-6
1E-5
1E-4
1E-3
0.01
0.1
1
10
1E-3
1E-4
1E-5
1E-6
1E-7
1E-8
1E-6
100
Energy (GeV)
1E-5
1E-4
Al1
1
0.1
0.01
0.1
1
10
100
Al2
1
0.1
0.01
2
2
0.01
1E-3
Energy (GeV)
10
d/dln(E) (particles/(cm *prim. particle))
10
d/dln(E) (particles/(cm *prim. particle))
d/dln(E) (particles/(cm *prim. particle))
10
2
d/dln(E) (particles/(cm *prim. particle))
10
1E-3
1E-4
1E-5
1E-6
1E-7
1E-8
1E-6
1E-5
1E-4
1E-3
0.01
0.1
Energy (GeV)
1
10
100
1E-3
1E-4
1E-5
1E-6
1E-7
1E-8
1E-6
1E-5
1E-4
1E-3
0.01
0.1
1
10
100
Energy (GeV)
Comparison between simulation and measurement presented last year. Agreement
very good. Dose close to beam loss point can be measured in a reliable way.
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CERN irradiation facilities
Location
Country
Facility
Particles
Energy
CERN
CH
PS-IRRAD1
p
23 GeV
CERN
CH
PS-IRRAD1
mixed
Secondary particles
used for SEU
tests
CERN
CH
PS-IRRAD2
n
~ 1 MeV (23 GeV p+C)
CERN
CH
GIF
γ
137Cs
740 GBq (1997)
CERN
CH
Building 27
γ
60Co
0.15 Gy/hour
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Flux
13
3x10
Contact at PH
p/hour/cm
50 mGy/hour
13
10
n/hour/cm
2
M.Glaser
M.Glaser
2
M.Glaser
M. Clayton
E. Auffray
Hillemans
12
External Facilities pi, p, n, ion
Location
Country
Facility
Particles
Energy
PSI
CH
piE1
pi
191 MeV
Flux
10
14
Contact at PH
π/day/cm
2
M.Glaser
up to 250 MeV
PSI
CH
PIF
p
(up to 5x5 cm2)
3x108 p/cm2/s
12
Ljubljana
SI
JSI
n
~ 1 MeV (reactor)
5x10
Louvain
BE
UCL-T2
n
<20.4 MeV> (d+Be)
7x10
Louvain
BE
UCL-Q
n
25 to 70 MeV (p+Li)
10 n/s
Louvain
BE
UCL-LIF
p
10 to 75 MeV
10 p/s/cm
Louvain
BE
UCL-LIF
ions
10 to 75 MeV
10 p/s/cm
Uppsala
SE
TSL
n
157
12
F.Faccio
2
n/cm /s
-1
n sr s
-1
6
9
2
9
2
7
F. Faccio
F. Faccio
2
FR
PROSPERO
n
~ 1 MeV (reactor)
Karlsruhe
DE
KAZ
p
20 to 42 MeV
1014 p/hour/cm2
-
Jyvaskyla
FI
RADEF
p
10 to 50 MeV
1010 p/s/cm2
-
LHC Radiation Day, B. Dehning
n/hour/cm
F.Faccio
2
Valduc
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10
K.Gill
F. Faccio
6x10 p/s/cm
14
M.Glaser
-
13
External facilities, gamma
Location
Country
Facility
Particle
s
Energy
Flux
Contact at PH
BNL
US
SSIF
γ
60Co
5x103 Gy/hour
-
Mol
BE
SCK-CEN BRIGITTE
γ
60Co
2x103 Gy/hour
K. Gill
Mol
BE
SCK-CEN RITA
γ
60Co
20x103 Gy/hour
K. Gill
Louvain
BE
UCL
γ
60Co
2x103 Gy/hour
Dagneux
FR
Ionisos
γ
60Co
1x103 Gy/hour
Geneve
CH
HUG hospital
γ
60Co
320 Gy/hour
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LHC Radiation Day, B. Dehning
E. Auffray
Hillemans
14
Robustness of IR3/IR7 Collimators
Acceptable beam loss to regular machine equipment and metallic
absorbers:
1e12 p at injection:
5e9 p at 7 TeV:
2e-5 of beam
Acceptable beam loss to C-C collimators/absorbers:
100 times better
3e13 p at injection:
10% of beam
robustness!
4e-3 of beam
8e11 p at 7 TeV:
3e-3 of beam
Maximum allowed loss rates at collimators (goal):
100 kW continuously.
500 kW for 10 s (1% of beam lost in 10s).
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Shielding and Radiation to Electronics
Gy/y
K. Tsoulou et al, LHC Project Note 372
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Location of Loss Detectors at IP8
N.
Location
IC
SEM
left
N.
Location
IC
SEM
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
BPMSW .1R8
1
1
MQXA.1R8
6
MQXB.A2R8
MQXA.3R8
6
6
TCDD.4R8
3
3
TCTV.4R8.B2
1
1
TDI.4R8
3
3
TCTH.4R8.B2
1
1
MBRC.4R8
1
1
MQY.A4R8
6
MQY.A5R8
6
MSIA.A6R8
3
3
MSIB.A6R8.
3
3
MQM.6R8
6
MQM.A7R8
6
MBA.8R8
6
right
1
2
3
4
5
6
7
8
9
10
11
12
13
14
BPMSW .1L8
1
MQXA.1L8
6
MQXB.A2L8
MQXA.3L8
6
6
TCTV.4L8.B1
1
TCLIA.4L8.B2
TCTH.4L8.B1
1
1
MBRC.4L8
1
MQY.A4L8
6
MQM.A5L8
6
TCLIB.6L8.B2
1
MQML.6L8
6
MQM.A7L8
6
MBA.8L8
MQML.8L8
6
MQML.10L8
6
20
21
22
23
24
MQ.11L8
1
1
1
6
MBA.8R8
6
MBA.11L8
19
1
6
MQM.9L8
MBA.11L8
1
6
MBA.8L8
15
16
17
18
1
6
6
17
18
19
20
6
MQ.13L8
6
MQ.14L8
6
MQ.15L8
6
MQ.16L8
6
29.11.2005
At every element
several detectors
mounted on:
cryostat
support
Detectors:
Ionisation chambers
Secondary emission
6
MQML.8R8
6
MQM.9R8
6
MQML.10R8
6
MBA.11R8
6
MBA.11R8
MQ.12L8
6
21
MQ.11R8
6
22
23
24
25
26
MQ.12R8
6
MQ.13R8
6
MQ.14R8
6
MQ.15R8
6
MQ.16R8
6
LHC Radiation Day, B. Dehning
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LHC Radiation Day, B. Dehning
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BACKGROUND SOURCES
SOURCES CONSIDERED [LPN258]
The “DISTANT” sources
Elastic beam-gas
Collimation “inefficiency”
Out-scattered halo not intercepted
by the collimators of the CS insertion
Elastic scattering in the cold sectors
between IR and CS insertion
Cleaning
[LPR500]
ONLY “elastic” products will be transported
downstream by the optics!
Interactions with residual gas in the IR
both elastic and inelastic
[LPR500]
Collisions in the neighbouring IP
P1IR8 probability distribution
Vadim Talanov CERN November 29 2005
21
NO QUENCH - NO BACKGROUND ?
TERTIARY BACKGROUND
The source is the halo out scattered from the IR7 and cleaned in the IR8 by the TCTs
Two tertiary collimators in each part of LSS8
Vertical TCT at D1, horizontal at D2
D2-D1 is the longest drift in SS
IR7
TCTH
Scoring plane
Heavy (tungsten) collimators
TCTV
FORMULATION OF THE PROBLEM
TCTs are here to protect D1-Q1 from quench
an aperture limitation in the IR
The “cleaned” protons will be converted to
a “tertiary” background towards the IP
LPN371: for elastic beam-gas losses TCTs in
[LPN371]
IR1 are the dominant background source
Vadim Talanov CERN November 29 2005
22
TERTIARY BACKGROUND (1)
SECONDARY PARTICLE FLUX AT THE IP8
TOTAL PARTICLE FLUX
Source: loss maps generated within Collimation Project
Vertical halo in TCTV and horizontal in TCTH
Charged hadrons Muons
VH@TCTV 3,66x106 1,05x106
Re-normalised for the 30 hours beam lifetime
LPN273: “1,03x106 muons/s … under the “3rd year
HH@TCTH 1,26x105 5,15x104
+90days” LHC running conditions…”
TOTAL
RADIAL DISTRIBUTION
TOTAL
Particle flux density f(r)
[particles/cm2/s]
For charged hadrons/muons
TCTH
TCTV
TCTH
Compared with LPN307
beam-gas estimates for
LPN307
TCTV
NO SHIELDING case
LPN307
Vadim Talanov CERN November 29 2005
23
BACKGROUND SHIELDING
SHIELDING PLUGS IN THE IR2/8
Detector protection from the background as inner/forward shielding at the P1/5
Proposed in 2002 [LPN307]
The closer to IP/beam line – the better Several installation constraints!
Specific design for left/right parts of SS
The possibility of a “staging” approach
Q1
P8
SS8L
Shielding
Shielding
Vadim Talanov CERN November 29 2005
24
TERTIARY BACKGROUND (2)
BACKGROUND IN THE PRESENCE OF THE SHIELDING
Combined model of simulations
BACKGROUND SHIELDING
Charged hadrons Muons
Same maps of the losses in the TCTs
Shielding introduced in the left part of the LSS8
Results compared to the previous TOTAL numbers
VH@TCTV 3,66x106 1,05x106
4.51x104 2.71x105
HH@TCTH 1,26x105 5,15x104
3.21x103 2.72x104
No shielding
No shielding
EFFECT OF THE SHIELDING
Charged hadrons flux
removed at large radii
Reduction factors
With shielding
charged hadrons: ~ 100
muons: 2÷4
With shielding
(depending on halo type)
…minor effect around
vacuum chamber…
Vadim Talanov CERN November 29 2005
25
LHC MIB WORKING GROUP
MACHINE INDUCED BACKGROUND WG
Forum on Detector Protection and Background Shielding
Established in 2005 by TS/LEA
Complex study of MIB problem
Analysis of the background formation
Minutes
Prediction of the dynamics
at different stages of machine operation
Reduction and rejection from the signal
COLLABORATION WITH OTHER GROUPS
The study of the machine background is cooperative
Collimation project
Vacuum group
Experimental collaborations
Reports
More information on WG pages at: cern.ch/lhc-background
Vadim Talanov CERN November 29 2005
26
European Space Components
Information Exchange System
See:
https://escies.org
Radiation
ESTEC - Radiation Effects and Analysis Techniques Section
Ref. : CERN, November 29, 2005.
ESTEC - Radiation Effects and Analysis Techniques Section
Ref. : CERN, November 29, 2005.
ESTEC - Radiation Effects and Analysis Techniques Section
Ref. : CERN, November 29, 2005.
ESTEC - Radiation Effects and Analysis Techniques Section
Ref. : CERN, November 29, 2005.
Radiation levels
•
Radiation levels in detectors and cavern simulated
with Fluka and Mars (crosschecked)
Total dose inside experiment
– Simulation safety factor: 2 (rather low)
•
•
•
Total Ionizing Dose,
1Mev neutrons
Hadrons above 20MeV (SEU, SEL, SEB)
– Clearly defined radiation hardness requirements for
10 years operation for all locations with electronics
web page: http://lhcb-background.web.cern.ch/lhcb-background/Radiation/SUMtable2.htm
•
•
•
•
•
•
•
•
Location
Velo & Pileup
IT & Muon
RICH1 front-end.
Muon crates
Cal crates
Bunker
Balcony
TID/rad
10M
1M
25k
10k
4k
1k
650
Neu/cm2
1014
1013
3*1012
1012
1012
1012
3*1011
Hadrons/cm2
1014
1013
3*1011
5*1010
3*1010
3*1010
6*109
Z
X
Gray/year
TID
Neutrons
Ecal detector
Racks
Radiation workshop
LHC Radiation Day,
31
Radiation hardness policy
•
Radiation hardness policy defined and agreed upon with all subsystems from the beginning
(at same time as defining front-end architecture)
– This took some time and we all had to educate our selves in this field that
was new to many (1999 – 2001)
•
Multiple meetings and workshops
– Ratified by LHCb technical board (2001)
– Radiation level simulations made
•
•
MARS: 1999 – 2000
FLUKA: 2001 – 2003 (still ongoing for locations with changes, e.g. LHC machine equipment)
– Safety factors
•
•
•
Simulation: 2
Components: ~10 (In certain cases we have had to accept lower values for this)
Testing: 2 (lower if justified)
– Failure types and rates:
•
•
Different risk factors in different locations (SEL, SEB) (accessible or not)
Different types of data (SEU):
–
–
–
–
–
•
Event data itself does not need SEU protection (like a bit of extra noise)
Event headers should be protected (system synchronization)
Control state machines must be protected
Configuration must be protected
Control interfaces must be very reliable (used to recover system when problems)
Reset procedures
– Qualification procedure (profiting from work done by ATLAS/CMS)
– All circuits used in detector and cavern MUST be radiation tested
– Verified during reviews
Radiation workshop
LHC Radiation Day,
32
Radiation hard/tolerant electronics
•
In detectors: ASIC’s
– ~12 LHCb specific ASIC’s
– Most implemented in 0.25um CMOS with radiation hard layout (enclosed
transistors) and triple redundant storage elements in critical parts (configuration
and control logic)
•
•
A few chips in 0.8 um BiCMOS
Radiation tests performed
– Use of LHC generic radiation hard circuits: TTCrx, GOL, QPLL, Delay25, linear
power regulator
•
In cavern or on periphery of detectors: Use of Commercial Of The Shelves
(COTS) components in many cases possible.
– Circuits must be tested or find reliable radiation test elsewhere (HEP, SPACE)
•
•
•
•
•
•
Total dose in most cases not problematic (modern CMOS)
Single event latchup problematic and must be avoided (with one exception in LHCb)
Neutrons does not affect modern CMOS circuits
Neutrons could be problematic for optoelectronics
SEU rates must be estimated to predict system reliability (not so easy)
Triple redundant logic in central functions (control, ECS) and when ever possible.
– Problem of traceability between tested circuits and final circuits mounted on
boards.
•
•
Significant time delay ( 1 - 2 years) between purchasing test samples and final quantities
Difficult to verify that circuits are made with identical processing
–
–
•
Change of Fab. ?
Internal/external second sourcing
We have been forced to take this risk
–
Radiation workshop
Doing our best to verify that technology and fabrication line have not changed.
LHC Radiation Day,
33
Commercial electronics (COTS)
•
Two types of FPGA’s have been found appropriate for use at limited (~10krad)
radiation levels in cavern
–
Antifuse FPGA:
•
No problem with corruption of configuration
(general reliability of antifuse have been problematic in the past)
•
•
No SEL seen in radiation tests of new antifuse series
Triple redundant registers needed for critical parts
–
–
Flash based FPGA
•
•
•
–
•
•
•
Small part of chip and therefore very small cross-section
We do not want to use SRAM configuration based FPGA’s (e.g. Xilinx)
Calorimeter board
It has been seen that chips in same technology and
same chip family has had different behavior (SEL)
In one case an ADC with a potential SEL problem (seen with ions) has dedicated
external protection circuit with self recovery.
12 way optical transmitter seen to have small cross section of short link errors
from “SEU”
–
–
•
Flash configuration does not get corrupted
No SEL seen in latest series (proASIC+)
Triple redundant registers needed for critical registers
General infrastructure logic may though be problematic
(startup, JTAG)
•
–
But can not be reconfigured either (nearly like an ASIC)
This could de-synchronize our readout/trigger and be problematic as 7000 optical links
used in LHCb
Enforced use of link idles to resync links on the fly.
We do not want to use microcontrollers , PLC’s and CPU’s in experimental
cavern.
–
One exception with ELMB having a dual checking processor and software with
watchdogs (ATLAS development and qualification)
•
I personally have some small worry on this, but mainly used for environment monitoring
Radiation workshop
LHC Radiation Day,
34
Optical links
•
•
•
•
•
~7000 optical links: L0 trigger and Readout links
GOL radiation hard serializer from CERN-MIC at 1.6Gbits/s
Single link transmitters with VCSEL directly modulated by GOL
12 way link transmitters using fiber ribbon optical modules
12way fiber ribbon receivers
–
–
•
•
~ 100 m fiber
2 inter-connections
~ 100 m fiber
2 inter-connections
Extensive qualification of links by individual groups
Standardized (and simplified) LHCb qualification procedure
–
–
–
•
Deserializers: TLK2501, Stratix GX FPGA, Xilinx Vertex 4 FPGA.
All receivers in counting house
GOL built in test pattern generator (counter, not pseudo random)
Bit error rate below 10-12 with additional 6db optical attenuation (1/2 hour test)
BER to be measured for 9db and 12db attenuation
Average power ~ 453 µW (-3.4 dBm)
Extinction ratio = 7.3 dB
BER ~ 10-16 @ eye opening > 60%
Total jitter ~ 215 ps @ BER 10-12
Link errors (bit, word and desync) could be problematic in final system
–
–
–
One 32 bit idle word enough to resynchronize link.
All L0 trigger links resynchronized in the large LHC bunch gap
All readout links have sufficient idles between each event fragment to allow link to
resync (not if PLL lost lock)
0.5 m
30 m
60 m
10 m
Wall
12 links
ribbon cables
MPO-MPO
transmitter
8 ribbon cables
MPO-SC
Cassette
Breakout cable
12 way fiber
ribbon receiver
Radiation workshop
LHC Radiation Day,
35
Radiation damages to cryogenic equipment (I)
From the radiation simulation results and irradiation tests
•Automates and Remote I/Os
1 functional interrupt per day,
‘Hard’ Single Events in modular power supplies ,
‘Soft’ Single Events in PLC and “intelligent” I/Os.
•Electro-pneumatic valve positioners (ref. tests of W. Hees- AT/ACR):
- in QURC (top and beam level platforms):
1 critical erratic valve position every 11 days (beam dump).
- in QUI (ground level):
1 critical erratic valve position every 77 days (beam dump).
29.11.2005A.-L. Perrot
TS/LEA
5th LHC Radiation Day
29/11/2005
Total Ionizing Dose
Horizontal cross-section @ beam level (y=0m)
Cryo equip.
1300
TID [Gy]
X [cm]
transversal axis
radial axis
Top-view
TID [Gy]
platform
beam axis
IP
Z [cm]
beam axis
magnet
radial axis
(radial distance from the beam axis)
ECAL-HCAL
29.11.2005A.-L. Perrot
TS/LEA
muons chambers
5th LHC Radiation Day
TID @ cryo equip. : 1-10 Gy for 10 LHC years
29/11/2005
1 MeV n. equiv. fluence- Displacement damage
Horizontal cross-section @ beam level (y=0m)
1300
Cryo. Equip.
1 MeV n. equiv [cm -2]
1 MeV n. equiv [cm -2]
axis
radial
X [cm]
Top-view
platform
beam axis
IP
Z [cm]
magnet
beam axis
(radial distance from the beam axis)
ECAL-HCAL
muons chambers
29.11.2005A.-L. Perrot
TS/LEA
5th LHC Radiation Day
1 MeV n. equiv. @ cryo equip.: 10
11
radial axis
– 10 12 /cm2 for 10 LHC years
29/11/2005
Hadrons (E>20MeV) fluence- Single events
Horizontal cross-section @ beam level (y=0m)
1300
Cryo. Equip.
hadrons (E>20 MeV) [cm -2]
hadrons (E>20 MeV) [cm -2]
X [cm]
axis
radial
Top-view
platform
beam axis
IP
Z [cm]
beam axis
magnet
radial axis
(radial distance from the beam axis)
ECAL-HCAL
29.11.2005A.-L. Perrot
TS/LEA
muons chambers
5th LHC Radiation Day
29/11/2005
Hadrons (E >20 MeV). @ cryo equip.: 10 9 – 10 10 /cm2 for 10 LHC years
TOTAL IONISING DOSE TESTS
Gamma (60Co) facility, CIS-BIO International CEA Saclay
PAGURE irradiator: (activity ~14 kCi)
POSEIDON irradiator: (activity ~1 MCi)
Dose rates:
• 30 Gy/hr to 1 kGy/hr (large volumes)
• 30 Gy/hr to 20 kGy/hr (small volumes)
Dose rates:
• ~ 2 kGy/hr
29.11.2005
LHC Radiation Day,
40