Wednesday Summary of Working Group IInitial questions I:

LHC LUMI 2005; 1.9.2005; Arcidosso Oliver Brüning 1

1) General boundary conditions:

Topic for presentations during the WG Goal of presentation Potential speaker

boundary conditions related to radiation present angular divergence of debris leaving the IP Tanaji Sen

present energy distribution of debris leaving the IP

present charge and mass distribution of debris

present estimates for total power contained in debris

present estimates for required absorber materials and thicknesswhat additional radiation shielding is required in the IR for a factor 10

higher luminosity?

present questions still to be addressed in future studies

magnetic TAS Assuming a TAS loaction between 19m and 23m from the IP what is the

required diple field for deflecting 90% of the charged debris to

amplitudes outside the nominal riplet aperture (63mm)? Does this

value scale with the total heat ;load and luminosity?

Tanaji Sen

Assuming a TAS loaction between 19m and 23m from the IP what is the required diple field for deflecting 90% of the charged debris to amplitudes outside a large triplet aperture (85mm)? Does this value scale with the total heat load and luminosity?

boundary conditions related to vacuum do we need beam screens in the triplet magnets

if yes, how much aperture do we need to allocate for them

Related questions given to the WG by the Work Shop Organizers

required triplet aperture and crossing angle

what are the minimum requried apertures of the experimental vacuum chamber for future detector upgrades?

Wednesday Summary of Working Group IInitial questions II:

LHC LUMI 2005; 1.9.2005; Arcidosso Oliver Brüning 2

2) Upgrade issues f or the detectors:

Question / Topic goal of presentation Potential speaker

radiation issues what are the upgrades to the ATLAS and CMS detectors needed to

withstand a factor 10 higher luminosity Fabrizio Palla

data taking issues what bunch spacing scenarios are acceptible for a luminosity upgrade

and how does they depend on the bunch luminosity?what changes are needed for the experimental beam pipes (aperture

and material choice)?

space requirements and L* how much can we reduce L* for a future detector upgrade Michael Bieler & can quadrupole magnets be integrated into the detector design in order to reduce L*?can quadrupole magnets be integrated into the detector design in order

to reduce L*? Can we learn something from the experience in other

machines (e.g. HERA)?

Peter McIntyre on

ironless quads with

integrated cooling

Related questions given to the WG by the Work Shop Organizers

what are the minimum requried apertures of the experimental vacuum chamber for future detector upgrades?

Wednesday Summary of Working Group Imain points from Tanaji Sen’s presentation I:

LHC LUMI 2005; 1.9.2005; Arcidosso Oliver Brüning 3

-peak power deposition inside the triplet magnets leaves a safety factor 4 for the quench limit (including 3mm orbit errors) for nominal operation how does the peak power deposition inside the triplet magnets scale with the orbit tolerances and how much can we increase the safety factor for the peak power deposition wih reduced tolerances on the closed orbit errors?

-peak power deposition inside the triplet magnets is a factor 3 to 4 above the quench limit of the triplet magnets any IR upgrade scenario requires an upgrade of the TAS absorber TAS length and material?

Wednesday Summary of Working Group Imain points from Tanaji Sen’s presentation II:

LHC LUMI 2005; 1.9.2005; Arcidosso Oliver Brüning 4

-two options for dealing with the increased heat load inside the triplet magnets:

1) construct more robust triplet magnets that can tolerate the increased peak heat load:

how does the quench limit of different super conducting materials vary and are there SC materials that provide higher tolerances on the peak power deposition inside the magnets?

Wednesday Summary of Working Group Imain points from Tanaji Sen’s presentation III:

LHC LUMI 2005; 1.9.2005; Arcidosso Oliver Brüning 5

-two options for dealing with the increased heat load inside the triplet magnets:

2) reduce the peak heat load with an upgrade of the TAS absorber:

how does the peak power deposition scale with the magnetic field strength and aperture of the magnets?

magnetic TAS: requires integrated field of 10 Tm <-> 20 Tm

Wednesday Summary of Working Group Imain points from Tanaji Sen’s presentation IV:

LHC LUMI 2005; 1.9.2005; Arcidosso Oliver Brüning 6

-peak power deposition inside the triplet magnets depends on the material of the vacuum chamber

-peak power deposition inside the triplet magnets depends on the orbit tolerances scaling?

Inner Triplet - baseline

Azimuthally averaged power density isocontours (mW/g) in the inner triplet of IR5

Peak power density - baseline

Peak power density in the first 2 radial bins for the baseline beam tube in Q1 and an alternative thinner tube.

Wednesday Summary of Working Group I

main points from Peter McIntyres’s presentation I:

LHC LUMI 2005; 1.9.2005; Arcidosso Oliver Brüning 9

-power deposition inside the triplet magnets increases with L* with one assumes the magnet diameter is proportional to L* move the triplet magnets further away from the IP

-discussion showed that it is still a good idea to reduce L* but assumption of constant aperture must be revised

-power density deposited inside the triplet magnets reduces with L* if the triplet aperture is kept constant move triplet magnets closer to the IP (scaling of losses with magnet field?)

Wednesday Summary of Working Group I

main points from Fabrizio Palla’s presentation I:

LHC LUMI 2005; 1.9.2005; Arcidosso Oliver Brüning 10

-CMS detector might offer potential magnet locations for L* = 14 m with radial space of +/- 0.5 m (currently occupied by TOTEM and CASTOR)

-ECAL installation is region of high radiation (L* = 3 m)

-evaluate pro & con of a fixed installation (compatibility with access and vacuum bake out) and a movable installation (tolerances for magnet and detector movements)

Muon chambers

Need better shielding of YE/4 (likely to be done before SLHC proper)

Need better shielding for ME/1

Wednesday Summary of Working Group I

main points from Fabrizio Palla’s presentation II:

LHC LUMI 2005; 1.9.2005; Arcidosso Oliver Brüning 12

-the situation for ATLAS is not as obvious (active area of the detector extends beyond TAS absorber) we might have to look for different IR layout solutions for the two main experiments

-the time required for an upgrade shut down must be balanced against a gain in integrated luminotisy see the talk by Michael Bieler

Wednesday Summary of Working Group Imain points from Michael Bieler’s presentation I:

LHC LUMI 2005; 1.9.2005; Arcidosso Oliver Brüning 13

-HERA luminosity upgrade features 6 new superconducting magnets inside the detectors (2m and 3.7m long)

-main problems related to the new installation:• water condenses on the cold magnets and drips into the detector• magnets are supported by steel cables and move by up to 1mm during the ramp• BPMs in the IR regions were initially exposed to synchtoron radiation

Wednesday Summary of Working Group Imain points from Michael Bieler’s presentation II:

LHC LUMI 2005; 1.9.2005; Arcidosso Oliver Brüning 14

-commissioning time for the HERA luminosity upgrade of 1.5 years to 2 years

the LHC IR upgrade must be robust in order to allowa fast commissioning time!

ZEUS Detektor

p

e

Vorwärts-Kalorimeter

Rückwärts-Kalorimeter

Zentrales-Kalorimeter

Solenoid Magnet

Zentrale DriftkammerCTDMikrovertex-Detektor

Wednesday Summary of Working Group Isummary:

LHC LUMI 2005; 1.9.2005; Arcidosso Oliver Brüning 16

-not all questions could be answered but interests and worries have been communicated to all parties involved

-many new questions

-interest in scaling laws and concrete layout models for comparative studies

-reduced L* is not excluded from the experiment (CMS) point of view

-complicated IR designs that might imply a long commissioning time!