Assembling
Assembling modules
modules into
into complete
complete VELO
VELO detector
detector
halves
halves
Tested parts shipped to CERN
Need to be assembled in complete detector halves
What final verifications ?
electrical tests
3D survey
cooling functional test
High voltage check out ?
In what details do we go ?
What precautions for handling ?
Schedule
FOR DISCUSSION WITHIN CERN/VELO GROUP
05-feb-2005
CERN – Geneva
Massimiliano Ferro-Luzzi
1
Expected
Expected parts
parts
42 modules from
Liverpool (4 from
NIKHEF)
Fully validated
(electronics,
mechanics,
alignment,
thermal,
vacuum, HV)
Mechanics and
interconnects
from Amsterdam
Fully validated
(cooling, vacuum,
electrical)
Instrumented RPT
crates from
Lausanne
Fully validated
Work
Work at
at CERN
CERN (overview):
(overview):
Check
Check single
single module:
module:
functional
functional
fast
fast cooling,
cooling, hi
hi volt
volt ??
Sample
Sample metrological
metrological check
check ??
Full
Full half:
half:
Full
Full metrology
metrology
Test
Test cooling,
cooling, HV,
HV, in
in vacuum
vacuum
o
Measure
Measure TTo effects
effects on
on 3D
3D (test(testbeam,
cosmics
or
other
?)
beam, cosmics or other ?)
FOR DISCUSSION WITHIN CERN/VELO GROUP
05-feb-2005
CERN – Geneva
Massimiliano Ferro-Luzzi
2
Who
Who are
are we?
we?
@ CERN:
Doris, Jan, Lars, Massi, Muriel (part of year), Paula, Raphael, Tomas
2 summer students, one stagiere (?) Kazu
Aldo (?)
Plus
Technical support from institutes, CERN metrology, DSF,
Russian Technician
Plus
Assembly shifters from Liverpool, Glasgow (under discussion)
FOR DISCUSSION WITHIN CERN/VELO GROUP
05-feb-2005
CERN – Geneva
Massimiliano Ferro-Luzzi
3
Evolution
Evolution towards
towards final
final assembly
assembly
cooling
Tests of preproduction modules
not necessary
“debugging”
ECS+safety
location
none
lab
partial
lab+DSF
manpower
flexible
Tests of single production modules
Homemade
system
Operation of >1 modules together on
base plate
“system test”
shift crews
Operation of full half
close to final
FOR DISCUSSION WITHIN CERN/VELO GROUP
05-feb-2005
essential: real
system
CERN – Geneva
DSF
in pairs with
strict rules
Massimiliano Ferro-Luzzi
4
Check single module
Discuss
Discuss with
with Liverpool,
Liverpool, customize,
customize, get
get drawings!
drawings!
1.
2.
3.
4.
a.
b.
c.
d.
e.
f.
g.
5.
Access
Access to
to its
its QA
QA data
data from
from Liverpool,
Liverpool,
Micron,
Heidelberg
Micron, Heidelberg
Module arrives in its transport box
Identify module and get info
Basic metrology check – cf database
Check electrical functionality:
possibility to input our results
and jointly analyse data
Chip digital functionality x 16 x 2
Chip currents and voltages
Pipeline map x 16 x 2
Ileak vs Bias scan
noise map of strips before and after cm
To sensors
Channel signal response x 2048 x 2 (?)
DAQ
DAQ &
& controls
controls for
for 16-Beetle
16-Beetle
read-out
read-out mode
mode (*)
(*)
Appropriate
Appropriate HV
HV and
and LV
LV PS
PS
Dark
Dark box
box
Cooling
Cooling
Radioactive
Radioactive source
source
Trigger
Trigger scintillator
scintillator ++ electronics
electronics
Store in transport box at DSF
(*) DAQ:
We do not probe anything directly on the module
(unless something is wrong)
We do not intend to rework module in terms of bonding
(hence cleanliness requirement can be relaxed –
proposal to be made to Liverpool)
FOR DISCUSSION WITHIN CERN/VELO GROUP
05-feb-2005
CERN – Geneva
at 40MHz, 4-output mode, 1 MHz
trigger rate ?
start with Jan’s setup (for single
sensor tests)
In parallel, develop TELL1 DAQ
then move to TELL1-based setup
(for multi-station tests)
Massimiliano Ferro-Luzzi
5
Single module setup (1)
For boosting my poor understanding of Jan’s DAQ… probably wrong
PC
Cable
Cable up
up both
both R
R and
and Phi,
Phi, such
such that
that
no
access
is
needed
to
study
the
no access is needed to study the
full
full module
module
Study
Study either
either R
R or
or Phi,
Phi, not
not both
both
simultaneously
?
simultaneously ?
Real
Real module
module looks
looks like
like that
that =>
=>
mechanics
mechanics needed
needed !!
What
What cooling
cooling ??
SSPCI
SSPCI
I2C + JTAG
PCI
CAT6 I2C
Dark box
CAT6 JTAG
crate
Scint
Phi side
8x
ADC card
For 2
Beetles
CAT 6 JTAG
8x
“Adapter”
CAT6 x 2
signals
8x
CAT6 x 2
signals
R side
CAT6 x 16
signals
CAT6
TFC
CAT6
I2C
Src
CAT6 TFC
CCB
board
CAT6 TFC
HV, LV, To
“Adapter”
“Adapter” == ??
1.
1.
2.
2.
FOR DISCUSSION WITHIN CERN/VELO GROUP
05-feb-2005
CERN – Geneva
RPT
RPT board
board with
with current
current PCB
PCB adapters
adapters ??
Passive,
custom-made
PCB
adapter
Passive, custom-made PCB adapter ??
Massimiliano Ferro-Luzzi
6
Single module setup (2)
WHAT
WHAT DO
DO WE
WE HAVE
HAVE ??
⇒
⇒ INVENTORY
INVENTORY
⇒
⇒ CAN
CAN // SHOULD
SHOULD WE
WE MAKE
MAKE MORE
MORE ??
⇒
⇒ BETTER
BETTER MOVE
MOVE TO
TO TELL1
TELL1 ASAP
ASAP !!
Electronics:
Electronics: the
the minimum
minimum config
config
22 Beetles/ADC
Beetles/ADC =>
=> 88 ADC
ADC cards
cards
44 ADC
ADC cards/SSPCI
cards/SSPCI =>
=> 22 SSPCI
SSPCI cards
cards
11 I2C+JTAG
I2C+JTAG PCI
PCI card
card
11 PC-linux
PC-linux for
for SSPCIs
SSPCIs
11 CCB
CCB board
board
22 “adapters”
“adapters” to
to connect
connect to
to the
the Kapton
Kapton
cables,
cables, which
which could
could be
be either
either one
one of
of
RPT
RPT board
board with
with current
current PCB
PCB adapters
adapters
Passive,
Passive, custom-made
custom-made PCB
PCB adapter
adapter
Trigger
Trigger electronics
electronics
TELL1
TELL1 –– BASED
BASED DAQ:
DAQ:
What
What do
do we
we need
need ??
Tell1
Tell1 crate
crate
Start
Start with
with one
one Tell1
Tell1 equipped
equipped with
with 11 to
to
44 digitizers,
digitizers, then
then expand
expand to
to about
about 10
10
Tell1s
Tell1s
Gigabit
Gigabit network
network and
and PC
PC
ECS
ECS ?? Via
Via what
what ??
Fast
Fast signals
signals ?? How
How ??
what
what cables?
cables? What
What length?
length?
Visit
Visit ED/online
ED/online lab(s)
lab(s) =>
=> Manfred,
Manfred, Niko
Niko ??
Visit
Visit EPFL
EPFL =>
=> Raymond,
Raymond, Guido
Guido
Work
Work out
out realistic
realistic delivery
delivery schedule
schedule =>
=>
Aurelio
Aurelio
Liverpool
Liverpool would
would like
like to
to have
have 33 such
such DAQs
DAQs !!!!
FOR DISCUSSION WITHIN CERN/VELO GROUP
05-feb-2005
CERN – Geneva
Massimiliano Ferro-Luzzi
7
Cooling for single module
Option 1:
Make a cooling block that matches with Liverpool module cooling interface
Use any standard liquid coolant with refrigerator
Connection must be flexible enough not to induce stresses on the module
Option 1a: cooling temperature should stay above dew point
Option 1b: provide also (pre-cooled) dry air into the dark box
Option 1c: put it in vacuum
Option 2:
Use fans
Must ventilate the whole box
Chip temperature will never be below room temperature…
FOR DISCUSSION WITHIN CERN/VELO GROUP
05-feb-2005
CERN – Geneva
Massimiliano Ferro-Luzzi
8
Checking one module (S, N): how much time ?
also probably all wrong…
Check electrical functionality:
a.
b.
c.
d.
e.
f.
Chip digital functionality x 16 x 2
Chip currents and voltages
Pipeline map x 16 x 2
Ileak vs Bias scan
noise map of strips before and after cm
To sensors
Pipeline
Pipeline map:
map:
Experience
Experience with
with test
test beam:
beam:
16
16 Time
Time Samples
Samples (TS)
(TS) gave
gave 33
kB/ADC
kB/ADC card
card
44 ADC
ADC cards
cards (( =1
=1 SSPCI
SSPCI card)
card)
⇒
⇒ 12
12 kB/16TS
kB/16TS ⇒
⇒ say
say ~1kB/TS
~1kB/TS
Expect
Expect SSPCI
SSPCI card
card can
can take
take at
at
least
least 11 MB/s
MB/s
Signal
Signal studies:
studies:
use
use TP
TP to
to do
do full
full pulse
pulse shape
shape study
study
limited
limited by
by DAQ
DAQ rate
rate (few
(few KHz)
KHz)
⇒
⇒ event
event rate
rate >> 11 kHz
kHz (1
(1 TS)
TS)
Everything:
Everything: << 2h
2h per
per hybrid
hybrid
pulse
pulse 22NN channels/chip,
channels/chip, at
at N
N << 44 ??
Require
Require ~~ 10kEvts/ch/TS
10kEvts/ch/TS in
in 44 TS
TS
Test more ?
Everything:
Everything: << 2h
2h for
for 44 TS
TS in
in 11 hyb
hyb
Linearity ?
Lower trigger rate ?
use
use Src
Src just
just to
to check
check strip
strip is
is OK
OK
…
Illuminate
Illuminate sensor
sensor (large
(large Scint)
Scint)
Define better:
Rate
Rate >> 11 Hz/strip
Hz/strip ??
require
require ~~ 11 kEvts/strip
kEvts/strip in
in 11 TS
TS
maximum DAQ rate
Maximum strip rate with source
Fast
Fast (few
(few minutes)
minutes)
FOR DISCUSSION WITHIN CERN/VELO GROUP
05-feb-2005
CERN – Geneva
Massimiliano Ferro-Luzzi
9
Checking one module (cool, HV): how much time ?
Fast cooling check: Time = order of 4 hours
cool down just a bit (in air) and measure temperatures on available sensors
Cross plot temperatures, look at gradients to assess thermal integrity without having to
cool down below zero
Final cooling check will be done in vacuum with a complete detector half => then repair
only faulty modules
Check high voltage: Time = order of days (if stability check)
Can only be checked in vacuum
Make a vacuum chamber for single module testing ? Investigate
Would allow also check of thermal integrity at nominal temperature
FOR DISCUSSION WITHIN CERN/VELO GROUP
05-feb-2005
CERN – Geneva
Massimiliano Ferro-Luzzi
10
Mount
Mount module
module on
on base
base plate
plate
Make a buffer of modules ( ~20 ?) before starting to populate a detector half
allows choosing positions of modules more pertinently
Requires a storage cabinet at DSF => define specs, buy
FOR DISCUSSION WITHIN CERN/VELO GROUP
05-feb-2005
CERN – Geneva
Massimiliano Ferro-Luzzi
11
Dept Silicon Facility
Dept Silicon Facility LINK
VELO
VELO has ~ 5mx5m
Class 100’000
Humidity 45+/-5%
Empty space now!
Equip VELO area with what ?
Cabinets for storage of modules (special or
standard low-cost ?)
Two (large, heavy) lab tables (~ 1m x 2m)
1.
2.
DAQ (console + cards + a few cables) for testing
individual module in a small dark box
For laying down a detector half and working on it
(may not be a table, but more like a custom-made
frame)
Two chairs
Nothing more !
(little space!)
FOR DISCUSSION WITHIN CERN/VELO GROUP
05-feb-2005
CERN – Geneva
Massimiliano Ferro-Luzzi
12
Dept Silicon Facility
Bringing a detector half in (weighs about 200 kg)
Car transport
Need small mobile crane with soft wheels to avoid damaging the
conductive floor (available at CERN ? Rent ?)
Air lock:
clean the device!
Cleaning procedure in air lock
Non-clean room
Clean room
Put on table
FOR DISCUSSION WITHIN CERN/VELO GROUP
05-feb-2005
CERN – Geneva
Massimiliano Ferro-Luzzi
13
VELO
VELO work
work
Main items for 2005:
VELO assembly tooling
Support structures (x2)
Base
Lifting devices
Cap
Protecting frames (cooling pipes, protection during
mounting, protection during survey)
Tooling for mounting modules, connecting kaptons
Mechanical supports for lab tests, individiual module
metrology, radioactive source test, individual module
handling etc.
Protection frame
for 3D survey
Lifting
devices
Cap
instrument space in Dept Si Facility
Base
Support
structure
In addition, continuous technical support
FOR DISCUSSION WITHIN CERN/VELO GROUP
05-feb-2005
~ 1.4 m
Towards 2006 and further:
Cosmics tests with det½ vertical, in vacuum, cooled
Test beam, idem
Installation at IP8
CERN – Geneva
Massimiliano Ferro-Luzzi
14
VELO
VELO Assembly
Assembly Tooling:
Tooling: Support
Support Structure
Structure (vert.)
(vert.)
Protection frame
for 3D survey
Support structure (vertical):
Holds det½ vertical
For working around modules:
Lifting
devices
Allows dis/mounting electronics crates
Possibility to fix the structure on a frame
Det½ laid down / taken off by crane
Leave some space under the det½:
for rotating the whole det½ around gravity
axis
possible hand access all around the detector
Cap
~ 1.4 m
Remember: cooling connection sticks out
on one side of det½
Base
Support
structure
FOR DISCUSSION WITHIN CERN/VELO GROUP
05-feb-2005
CERN – Geneva
Massimiliano Ferro-Luzzi
15
VELO
VELO Assembly
Assembly Tooling:
Tooling: Base
Base
Protection frame
for 3D survey
Frame:
Lifting
devices
Holds support structure
For working around modules
Allows dis/mounting electronics
crates
Allow for overall height adjustment
+/- 5 cm ?
Cap
Det½ laid down / taken off by crane
Leave some space under the det½:
~ 1.4 m
for rotating the whole det½ around
gravity axis
possible hand access all around the
detector
Base
NB take care for cable routing to
racks
Support
structure
FOR DISCUSSION WITHIN CERN/VELO GROUP
05-feb-2005
CERN – Geneva
Massimiliano Ferro-Luzzi
16
VELO
VELO Assembly
Assembly Tooling:
Tooling: Lifting
Lifting Devices
Devices
Lifting devices:
Protection frame
for 3D survey
Det½ laid down / taken off by crane
Allow rotating det½ around gravity axis
Compatible with craning in VELO lab, Dept Si
Facility and metrology
Lifting
devices
Must mount det½ from and into “vacuum cart”
Load up to ~ 300 kg
Cap
?
~ 1.4 m
Base
Cooling sticks
out from this
side !
“unremovable”
FOR DISCUSSION WITHIN CERN/VELO GROUP
05-feb-2005
CERN – Geneva
Support
structure
Massimiliano Ferro-Luzzi
17
VELO
VELO Assembly
Assembly Tooling:
Tooling: Lifting
Lifting In
In Horizontal
Horizontal Position
Position
FOR DISCUSSION WITHIN CERN/VELO GROUP
05-feb-2005
CERN – Geneva
Massimiliano Ferro-Luzzi
18
VELO
VELO Assembly
Assembly Tooling:
Tooling: Cap
Cap
Protection frame
for 3D survey
Cap:
Dark box for tests
Protects when no work ongoing
Lifting
devices
Possible to flush with N2 or dry air:
In/outlet connections at the top
Grossly sealable to hood O-ring
Side handles for easy dis/mounting
Cap
Dismountable guiding rods foreseen on
hood for dis/mounting cap without
interferences
~ 1.4 m
NB The cap must be mountable SAFELY in
the horizontal position (or any rotation)
Base
Support
structure
FOR DISCUSSION WITHIN CERN/VELO GROUP
05-feb-2005
CERN – Geneva
Massimiliano Ferro-Luzzi
19
VELO
VELO Assembly
Assembly Tooling:
Tooling: Frames
Frames
Frames:
Protect bare cooling pipes during transport and module mounting
Protect already mounted modules during module mounting
Protect modules during survey
Avoid destroying modules by mounting and dismounting too many protections
Cooling pipe frame proposal:
FOR DISCUSSION WITHIN CERN/VELO GROUP
05-feb-2005
CERN – Geneva
Massimiliano Ferro-Luzzi
20
VELO
VELO Assembly
Assembly Tooling:
Tooling: Frames
Frames
Mounting frame proposal (must fit over cooling frame protection?)
“clickable” access window
Cover top or sides also? How dangerous is mounting/dismounting?
Room to “stick out” (especially for metrology)
FOR DISCUSSION WITHIN CERN/VELO GROUP
05-feb-2005
CERN – Geneva
Massimiliano Ferro-Luzzi
21
VELO Assembly Tooling for Mounting Modules
Tooling for mounting modules:
Structure that holds cooling blocks when
not attached to modules
Protection frame
for 3D survey
Lifting
devices
Structure that guides module frame when
inserting module
Structure that prevents parts to fall into the
hood
Cap
Tools that allow un/locking modules,
cooling connections and interconnects
Etc.
~ 1.4 m
Frame
Support
structure
FOR DISCUSSION WITHIN CERN/VELO GROUP
05-feb-2005
CERN – Geneva
Massimiliano Ferro-Luzzi
22
CERN
CERN metrology:
metrology: survey
survey of
of complete
complete half
half
CERN Metrology Lab (EST/MF)
Olivetti CNC (600x900x1600 mm3)
on air-cushion with granite base, ±
3um precision
~ 750
~ 1100
Optical and touching head
Measure first downstream sides of
all modules, then turn head and
measure upstream sides.
Detector half will be laid down in
same poistion as in the VELO
Real measuring precision and
technique under investigation
FOR DISCUSSION WITHIN CERN/VELO GROUP
05-feb-2005
CERN – Geneva
Massimiliano Ferro-Luzzi
23
CERN
CERN metrology:
metrology: survey
survey of
of individual
individual module
module
Can be done
at CERN metrology lab
or in DSF, with new machine (but
what is the technical support)
Idea is to make just a few
measurements in order to
Have a point of reference to
compare with Liverpool database
Make sure the module will fit inside
the foil (!)
fiducials
(well defined
wrt to sensor edge)
FOR DISCUSSION WITHIN CERN/VELO GROUP
05-feb-2005
Base?
Where to measure?
CERN – Geneva
Massimiliano Ferro-Luzzi
24
Tooling
Tooling for
for 3D
3D Survey:
Survey: Support
Support Structure
Structure
Measuring head
Support structure 2:
Holds det½ horizontal
Det½ laid down / taken off by crane
For working on a CERN’s metrology CNC
Should fit in CERN’s CNC !
Stable, stiff !
No electronics crates
Protection frame
Adjustable height/level ?
Support structure
Questions to NIKHEF:
Should we hold fixed the detector base plate or is it stiff enough
w.r.t. hood ?
Are there attachment points foreseen on the hood ?
Where is the center of gravity of det½ ?
Can the screw in the round flanges be sunk into the flange ? (or
dismount flange? Cleanliness issue?)
FOR DISCUSSION WITHIN CERN/VELO GROUP
05-feb-2005
CERN – Geneva
Massimiliano Ferro-Luzzi
25
Tooling
Tooling for
for 3D
3D Survey:
Survey: Protection
Protection Frame
Frame
Protection frame
Protection frame:
For protecting modules from CERN’s
3D optical head
y
z
Allows head to enter between
modules, but not physically touch
modules (constrained in z and x!)
modules
Must allow access to survey
references on modules (positions yet
to be defined)
Approximate “forbidden” area in light
yellow:
Should fit into the “vacuum cart” ?
holes? trap doors?
What reference points should be
measured on the base plate (if any?)
FOR DISCUSSION WITHIN CERN/VELO GROUP
05-feb-2005
CERN – Geneva
Massimiliano Ferro-Luzzi
26
How
How to
to support
support detector?
detector?
FOR DISCUSSION WITHIN CERN/VELO GROUP
05-feb-2005
CERN – Geneva
Massimiliano Ferro-Luzzi
27
How
How to
to support
support detector?
detector?
FOR DISCUSSION WITHIN CERN/VELO GROUP
05-feb-2005
CERN – Geneva
Massimiliano Ferro-Luzzi
28
When detector half is supported from hood there are significant
deflections. Is it possible to support the half from the grooves in the
same way as in the experiment?
FOR DISCUSSION WITHIN CERN/VELO GROUP
05-feb-2005
CERN – Geneva
Massimiliano Ferro-Luzzi
29
Vacuum
Vacuum Chamber
Chamber (Amsterdam)
(Amsterdam)
Functionality:
Test det½ in vacuum (with CO2 cooling ON)
Store detector half
Transport detector half
Test beam
Vacuum chamber should be detachable from
transport cart
It should be possible to orient the vacuum
chamber (with det½) vertically for cosmics
measurements
High vacuum compatibility is enough (~1e-5
mbar)
Use guides for inserting/removing the det½
Need to define:
Lifting and attachment points
lifting devices
ports: entrance and exit holes (diam ~10 cm),
centered on sensor centers, to allow putting thin
entrance windows
Can the vacuum vessel be modified to also
provide the proper support? Need extra flange,
lifting mechanics etc. -> Q to NIkHEF
FOR DISCUSSION WITHIN CERN/VELO GROUP
05-feb-2005
CERN – Geneva
Massimiliano Ferro-Luzzi
30
Cosmics (1)
Main purpose: check internal alignment while cooling down
Approx rate for vertical detector half:
Flux per unit area
θ
cosθmax
= ∫0
Iv x3 dx dφ (with x = cosθ)
= π/2 . Iv . (cos4θmax - 1)
= ~ π Iv tg2θmax
θmax is an “average” or “typical” max polar angle for going through a
given N-station telescope
Say, roughly: tgθmax = R/2L = smallish
“Hard” vertical flux: Iv = 8 mHz cm-2 sr-1
(3 for “soft” comp)
L
R=4.2 cm
= 25 mHz cm-2 . (R/2L)2 . π R2/2
= 0.6 Hz . (R/2L)2
4 central stations: L = 9 cm
For L = 10 cm: ~ 25 mHz or 90 evts/hr
3 downstream stations: L = 10 cm
Flux thru Telescope
How many of these are useful ?
FOR DISCUSSION WITHIN CERN/VELO GROUP
05-feb-2005
CERN – Geneva
Massimiliano Ferro-Luzzi
31
Cosmics (2)
Multiple scattering
Average “hard” component: muons with p=~4 GeV
Small pitch region (only 600 um Si), perpendicular tracks
This gives an angular width: θ0 = 220 urad
Or, 3 cm downstream, a random displacement by ~7 um
This may be OK for seeing relevant thermal displacements
But θ0 scales linearly with 1/p
How do we trigger efficiently once we have a full detector half
in vacuum ?
FOR DISCUSSION WITHIN CERN/VELO GROUP
05-feb-2005
CERN – Geneva
Massimiliano Ferro-Luzzi
32
Safe work on modules
Define a set of rules for working on the VELO:
Not more, not less than two persons in the VELO area/room
THIS ALSO APPLIES TO SURVEY
One person works on VELO, the other one watches
Do not wear “loose” items (pens in pockets, necklaces, hair decoration,
baggy clothes, mobile phone on your belt, etc.)
Never work more than X hours per day in the VELO area/room
Stay calm ☺
Keep the area clean and ordered (no items, cables, etc. lying on the floor
across the pathways, XXX)
Do not approach module unless for working on it
Avoid passing items, arms, etc. over the modules
Always know exactly what you are going to do on the module before going
for it!
…
Write this on a leaflet and circulate, post at entrance door, etc.
Note: for maniacs, there are training courses at CERN for clean rooms
FOR DISCUSSION WITHIN CERN/VELO GROUP
05-feb-2005
CERN – Geneva
Massimiliano Ferro-Luzzi
33
Next
Next Steps?
Steps?
Set up web page with information, in cases with proposals
Obtain missing information from NIKHEF, Liverpool, Lausanne
In next weeks, define mini milestones for
DAQ requirements
ECS requirements
mechanics
metrology (including software requirements)
Ready to be part of module PRR
Integration with testbeam planning
FOR DISCUSSION WITHIN CERN/VELO GROUP
05-feb-2005
CERN – Geneva
Massimiliano Ferro-Luzzi
34