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Single shot test beam at PS!
Simulation of a beam loss!
Joint ad
venture
Joint
ventureofof
CMS and ATLAS
General Tracker Meeting 07/2002
Frank Hartmann
1
Some LHC numbers
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Proton energy
7 TeV
Particles per bunch
1011
Number of bunches
2835
Stored beam energy
336 MJ
Beam current
0.5 A
Failure: magnet quench; power converter fail, etc.
dipole or quadrupol failure decaying B-field
 need to dump
• Revolution time: 90µs
• Abort gap:
3,17µs
• Kicker rise time: 3µs
Canwewe
imagine
Can
even
imaginea adump
beam failure?
„lost“ in IP1 or IP5?
General Tracker Meeting 07/2002
Frank Hartmann
LHC layout and hint for
beamloss reason
Mika Huhtinen:
• Single module prefire:very unlikely
Assumption only one of the
14 abort kicker fires
 4*10^13 protons lost in IP 5
• Unsynchronized abort: very likely
Assumption one of the dump
kickers does not hit the abort gab
 bunch swept out for ~3µs;
some deviated bunches
continue in the machine
1*10^12 protons lost in IP 5
MC: STRUCT;MARS;FLUKA
IP5
IP6
!!DUMP near to IP5 (CMS)!!
General Tracker Meeting 07/2002
Frank Hartmann
Improbable things are not
impossible!
• Both prefire and unsynchronized accidents
happend at the TEVATRON!
• BUT: Less critical at the TEVATRON!
• They are improbable at LHC!!??!!
!
RA EPAC02
General Tracker Meeting 07/2002
Frank Hartmann
Beam conditions at the PS
cut
Fast extraction => spill ~ 100 ns duration
Up to 1011 protons per spill (109 to 1010/ cm²)
24 GeV protons
Beam spot: Starting 2-3cm diameter beam spot,
but we expect to be able to tweak the last
quadrapole to have cigar shaped beam spot.
– We are currently investigating if a 10cm diameter spot possible?
• Dosimetry to be handled by T7 group
(secondary emission counter, gold or nickel foils).
• beam available for 8 hour shift, installation 1.5 days
• beam conditions fixed: 26.7.02
General Tracker Meeting 07/2002
Frank Hartmann
8cm
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T7 Area
General Tracker Meeting 07/2002
Frank Hartmann
THE WHY!?!
• No integral effect expected (worst case = 10 days)
• But large instantaneous ionization! 1011 MIPS
1. Will our modules survive a beamloss?
–
–
Is our design robust?
Simple YES/NO test!
2. What is the dynamic behaviour?
–
Possible failure analysis!
ALL PARAMETERS will be dynamically checked
slow (10µs) and fast (50ns) (Scopes/FADCs)
General Tracker Meeting 07/2002
Frank Hartmann
Specific Questions
1. Will the hybrid survive?
2. ..............sensor survive?
3. ..........complete module survive?
 Disentanglement of components!!
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How many beam losses are digestable?
Check for bias voltage dependencies?
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Which component of the components breaks, if any?
General Tracker Meeting 07/2002
Frank Hartmann
Setup



cooling box available (-10°C)
(thanks to ATLAS)
2 devices per carrier
devices premounted in
carrier incl. patch panel
General Tracker Meeting 07/2002
Frank Hartmann
Carrier
3 ready in KA
General Tracker Meeting 07/2002
Frank Hartmann
Scenario
1.
2.
3.
4.
5.
Place carrier (DUT) in cold box
Full characterization in situ
SINGLE 100ns beam spill
Full characterization in situ
2.-4. with different conditions
6. Place new carrier (DUT) ...(3 boxes=times).....etc.
•
Full characterization in home lab;
hopefully NO failure analysis 
General Tracker Meeting 07/2002
Frank Hartmann
3 carriers / tests
1st carrier: HPK-sensor + hybrid (flex)
Vbias ramp : one shot per ramp point
(0..100V in steps of 20V and 100..400V in 50V-steps)
2nd carrier: ST-sensor + good TEC module
3rd carrier: HPK-sensor + KA prototype TEC module
(some pinholes, current..)
after ~30 consecutive beam dumps:
detect if the module is still alive!
General Tracker Meeting 07/2002
Frank Hartmann
Parameters on sensors
1.
2.
3.
4.
Ionisation: completely destroy field configuration/depletion!
Sensor is short circuited!  worst case 400V on CC!!
Furtunately the power supplies will not react on that time scale!
Still: Dynamics are complicated and we will try to measure them!
0V
Readoutstrips
+400V
HV: voltage&current!
HV: voltage&current!
Single strip
strip current!
current!
Single
(also check
check for
for Rpoly)
Rpoly)
(also
Voltage over CC: Pinholes?
CCbreak>120V
(also check for potential on
APV)
General Tracker Meeting 07/2002
Frank Hartmann
Sensor parameter
• HV:
bias voltage
• Ileak: global leakage current
• VAC_DC: Voltage between AC and DC-pads of several
groups of strips. 2 or 3 groups are planned!
• IDC_biasresistor: also done for 2 or 3 groups of strips
• Iguard: current possibly induced in the guard ring
= 9 parameters (3 groups)
sensors on PCB (circuit discussed with RH)
 all parameters measured with scopes or FADCs
General Tracker Meeting 07/2002
Frank Hartmann
Strip parameters
Single strip current
measurement
Scope (measure I)
Scope (measure V)
Voltage over SiO2
to estimate pinhole
development
General Tracker Meeting 07/2002
Frank Hartmann
Test on hybrid (bare and on module)
Parameters:
•V250: 2.5V hybrid supply voltage
I•250
•V125: 1.25 supply voltage
I•125
= 4 parameters (measured with scopes)
(voltages refer to hybrid ground level)
Readout
•Standard: APV: Noise, ped, calib
General Tracker Meeting 07/2002
Frank Hartmann
Readout in situ (APV,module)
Use own Karlsruhe CMS-like readout system
(good knowledge of the software)
1.
Prequalification with normal procedures: pedestal,
noise, common mode, calibration, LED, laser?
2.
TRIGGER: increase of sensor leakage current
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send APV reset
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when APV tickmarks are found:
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send software triggers and search for header
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monitor baseline behaviour if header is found
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Laser response?
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LED response
3.
Later: full qualification (noise,ped,calib,LED)!
General Tracker Meeting 07/2002
Frank Hartmann
Module parameters
all hybrid parameters
• HV + Ileak
• Full readout
• LED and perhaps laser response
•
= 6 parameters (measured with scopes)
Reminder: one SINGLE shot  full qualification!
Carrier 2&3: Sensor+module will sum up to 30 scope channels!
General Tracker Meeting 07/2002
Frank Hartmann
Readout adventure
Readout over 30m of cables!
1. Optical readout:
Most promising and probably the only reasonable
– Still parts missing
– So far NO experience in KA
2. Cat. 7 network cable (needed anyhow for control)
(backup 1)
3. PC in the „hot“ area, controlled via LAN (backup2)
Cables have to be installed!
Power supply combined effort with ATLAS
General Tracker Meeting 07/2002
Frank Hartmann
One shot schedule
Set up of One-shot beam
Time required =1.5 days
Conditional on successful replacement of
PS power supply and re-establishment of
slow extraction beam line
FIRST 100ns beamGeneral
extraction
ever done at
Tracker Meeting 07/2002
the PS (standardFrank
~ms)
Hartmann
Possible time slots
Duration =8 hours (max)
Summary
• Our electronics plus detectors should be prepared
to survive fast pulses with several orders of
magnitude higher particle rates than in nominal
conditions.
• We „SHOOT“ a hybrid, 2 modules, 3 sensors with
1011 protons several times varying the bias voltage!
• We are aware that the existing program is very
ambitious and the available time is tight, therefore
help is welcome!
• Additional ideas/devices like a CCU is feasible,
if additional groups join the venture!
• Scopes still needed!
• The project is a joint adventure of CMS & ATLAS
• The LHCC referee welcomes the project
General Tracker Meeting 07/2002
Frank Hartmann