Transcript transparencies - Indico

m1
Ivan Belyaev
LHCb, CERN & ITEP/Moscow
m-1
• Could we use it?
• “in addition” to Spd
• How to use it?
• Non-trivial !
• Large L
• ‘Pads’ do not match
• Last LHCb-light +
computing meetings
• “Base-line” for m1
•
18% X0
cells
• No ‘pads’ at all
• Vital for veto ??
17 June'2k+2 Computing
Ivan Belyaev LHCb CERN & ITEP/Moscow
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Muon Station
Layout
The Muon System has a
projective layout. (The
dimensions shown are for M2)
The chambers indicated in
“gray” are in front of the
support structure, and those
in “white” are behind the
support structure, leaving
free rows for cables etc.
FE-boards are mounted on
the chambers and the cables
run on top of the chambers
in the empty rows.
17 June'2k+2 Computing
Ivan Belyaev LHCb CERN & ITEP/Moscow
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Chamber Layout
Chamber description
in SICB MC
17 June'2k+2 Computing
Chamber design as in TDR
Ivan Belyaev LHCb CERN & ITEP/Moscow
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Material Budget
(slide from last week meeting)
Present SICMC:
(all numbers given are averaged over the full surface)
• 8.2% X0 FR4 sheets (1.6mm thick -> should be 0.8mm)
• 3.5% X0 Copper on the cathodes (50mm/layer)
• 0.6% X0 Honeycomb structure
• 2.3% X0 Support structure (2mm Al)
-> 14.4% X0
Drawbacks:
•
•
•
•
•
•
No overlap of the chambers is in, which brings the numbers up by 40%
No chamber border is in, which adds about 4% X0
The baseline panel material is polyurethanic foam, which adds 6% X0
No cables and connectors are in, which adds about 2.5% X0
No FE-boards and connectors are in, which adds about 5.5% X0
The Al support is 3mm instead of 2mm (+1.1% X0)
Comments:
• Starting point for muon group is to use design as similar as possible
to the design M2-M5
-> Adjustments are certainly required!
• No work on specific M1 design has been done up to now, besides
first studies on number of gaps (4 vs. 2 gaps)
17 June'2k+2 Computing
Ivan Belyaev LHCb CERN & ITEP/Moscow
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Material Budget
16.5 % X0 for 2 gaps Comparison 4 gaps versus 2 gaps:
•
•
•
•
Chambers
FE-boards
Cables
Total
4 gaps
25.5
5.5
2.5
33.5% X0
2 gaps
16.5
5.3
2.2
23% X0
Where could we gain:
• The use of Honeycomb panels should be considered (at some cost due
to more difficult construction), which would reduce the material
budget by 6% X0 (4 gaps), respectively 4% X0 (2 gaps)
• In case the particle flux went down significantly, the number of
FE-boards could go down by 43% or 2.4 % X0
-> The optimal possible would be ~24 % X0 for 4 gaps and
17 June'2k+2 Computing
Ivan Belyaev LHCb CERN & ITEP/Moscow
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Proposal
What could be done next:
The present muon software allows to add easily some material in the
chamber border, which is the place where most of the material sits.
We suggest to do it this week, to allow a quick performance study with
a more up to date layout.
Maybe two small datasets could be generated, one for the 4 gap and
one for the 2 gap configuration, to compare the performance for
electron trigger and photons.
-> Muon group needs feedback from calo group to know where we are
-> This would be important input for a layout optimization
17 June'2k+2 Computing
Ivan Belyaev LHCb CERN & ITEP/Moscow
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