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13-Feb-2014 Phase 2 upgrade “ME0 stack options” J. Hauser, UCLA In Shashlik and CFCAL HE designs, space of z~30 cm exists behind 10 lambda for muons 30 cm typically allows 2 overlapping chambers, each of thickness 10 cm plus 4+4 cm on each side for borated polyethylene and Pb shielding for neutrons On the other hand, in HGCAL, a tail catcher of hadron showers is currently implemented as potentially dual purpose with ME0 muon detection In fact this design is not being used for muon reconstruction yet Some thoughts following conversations with Valeri Andreev, Roger R, Marcello M, Archana, Karl Gill, Alain Herve, Pawel… 1
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13-Feb-2014 Phase 2 upgrade “ME0 stack options” J. Hauser, UCLA Proposed at ECFA workshop
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13-Feb-2014 Phase 2 upgrade “ME0 stack options” J. Hauser, UCLA Support of HE mechanical load and moment: Bolts at outer radius Sliding joint to strong back at inner radius
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13-Feb-2014 Phase 2 upgrade “ME0 stack options” J. Hauser, UCLA Version A) Shashlik and CFCAL sims: 1x6 layer chambers, HE support from sliding joint to fixed-r conn. to strong back: requires ME0 inner, outer sections Version B) HGCAL sim: 4x1 layer chambers, 0.47 and 5.1 X 0 between measurements ~36 cm ~4 cm ~8 cm muon HE strong back - stainless ~10 cm ~8 cm ~4 cm 6-layer chambers 6-layer chambers 2.5 borated polyethylene 1.2 Pb for n shielding 0.90 cm 3.45 cm 0.90 cm … 34.8 cm Brass absorber Brass spacer 3.45 cm Brass absorber Brass spacer
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13-Feb-2014 Phase 2 upgrade “ME0 stack options” J. Hauser, UCLA From Virdee Euroschool 2003… tail catching
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13-Feb-2014 Phase 2 upgrade “ME0 stack options” J. Hauser, UCLA A (6-layer chambers): Pros “Traditional” muon chamber design like CSC, DT 6 muon layers versus 4 layers Internal alignment is precise Cost savings Lots of space to bring ME0 services, cables Cons Likely not a good HE calorimeter tail catcher Mechanical support is more complicated B (single layer chambers) Pros Good HE calorimeter tail catcher Simple mechanical support Cons 4 muon layers versus 6 layers Alignment concerns Increased cost Almost no space for ME0 services except at outer periphery, extremely thin packages required
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13-Feb-2014 Phase 2 upgrade “ME0 stack options” J. Hauser, UCLA Version C) 3x2 layer chambers, 0.54 and 6.0 X 0 between chamber measurements Version D) 2x 3 layer chambers, 0.77 and 8.6 X 0 between chamber measurements 2.3 cm 3.4 cm 2.3 cm … 34 cm 3.4 cmBrass absorber Brass spacer Brass absorber Brass spacer 2-layer 4.0 cm 4.5 cm 4.0 cm … 4.5 cm 34.2 cm 3-layer Brass spacer Brass absorber 3-layer Brass spacer Brass absorber 3-layer Brass spacer Brass absorber 3-layer Brass spacer Brass absorber
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13-Feb-2014 Phase 2 upgrade “ME0 stack options” J. Hauser, UCLA C (3 x 2layer chambers) Pros Familiarity with 2-layer packages from GE1/1 etc Pretty good HE tail catcher Cons Thicker brass spacers – is it a mechanical problem? D (2 x 3layer chambers) Pros Muon radiation isolation between successive chambers (more X 0 in brass, is it enough?) Fair HE tail catcher Cons Unfamiliar package Even thicker brass spacers – is it a mechanical problem? 8
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13-Feb-2014 Phase 2 upgrade “ME0 stack options” J. Hauser, UCLA 2-layer Version E) 2-layer units increases lever arm/pointing by a factor 2 2-layer units also convenient for construction (similar to GE1/1) In Shashlik and CFCAL sims: 1x6 layer chambers HE strong back - stainless ~4 cm ~10 cm 2-3.2 cm ~4 cm 2-layer ~7 cm ~36 cm ~4 cm ~8 cm HE strong back - stainless ~10 cm ~8 cm ~4 cm 6-layer chambers 6-layer chambers 2.5 borated polyethylene 1.2 Pb for n shielding ~36 cm 2.5 borated polyethylene 1.2 Pb for n shielding ~17 cm
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13-Feb-2014 Phase 2 upgrade “ME0 stack options” J. Hauser, UCLA ME0 is used for muons to link to inner Tracker tracks Especially at highest eta, Tracker uses endcap pixel disks Error ellipse is therefore likely to be rather round Pads, therefore, are better for matching than narrow strips This also favors use as a tail catcher in a projective calorimeter But ignores the possibility of modest rejection of low-Pt muon candidates Skinny radial strips best for this Studies are needed to identify the dominant effect?
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13-Feb-2014 Phase 2 upgrade “ME0 stack options” J. Hauser, UCLA Verify the numbers, at least approximately Try to install version A stack in HGCAL sim for now HE: tail catcher capability doesn’t see to be high priority for studies, HGCAL group has expressed their flexibility “Give” or at least “lend” the 34.8 cm space in z (and the cost) to the muon community for optimization Z= 5193 – 5541 mm in present HGCAL (V.Andreev xml layout) Later on, versions C (3 x 2layer HE-like) and E (staggered 3 x 2-layer muon units) look to be attractive alternatives for all HE choices
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13-Feb-2014 Phase 2 upgrade “ME0 stack options” J. Hauser, UCLA
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Brass density 8.4-8.73 (casting, rolling variations) Composition 63% Cu and 37% Zn by weight At 8.4, density of Cu=5.292 g/cm 3, density of Zn 3.108 g/cm 3 At 8.73, reduce interaction and rad lengths by 3.93% Interaction lengths, radiation lengths Cu =137.3 g/cm 2, X 0 =12.86 g/cm 2 Zn =138.5 g/cm 2, X 0 =12.43 g/cm 2 Interactions add up weighted average of the / and /X 0 For 63/37 brass, calculate =16.4 cm, X 0 =1.511 cm
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13-Feb-2014 Phase 2 upgrade “ME0 stack options” J. Hauser, UCLA Valeri 1.0 for EE 0.3 for EE stainless back 4.0 for Si-brass 4.15 for Scint-brass 9.45 in front of GEM 1.85 for GEM-brass Me: 1.0 for EE (take as a given) 0.3 for EE stainless back 3.9-4.07 for Si-brass 4.28-4.45 for Scint-brass 9.48-9.82 in front of GEM (or 0.03-0.37 higher) 1.90-1.98 for GEM-brass
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13-Feb-2014 Phase 2 upgrade “ME0 stack options” J. Hauser, UCLA
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(0, 5, 10, … cm)
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