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Hcal Geometry and Assembly Videoconference January 2008, 24th
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24/01/2008VideoconferenceNicolas GEFFROY 2 Study of a new Hcal geometry… …motivation: « cracks » in the calorimeter Classical geometry ( muons are lost, hadrons ? )
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24/01/2008VideoconferenceNicolas GEFFROY 3 Study of a new Hcal geometry… In order to avoid cracks, the edges should not point to the center of the barrel Proposal of a first tilted geometry First version : The edges are tangent to a circle, centered on the beam axis. The circle radius is the parameter which determinates the tilt level - 1 st version -
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24/01/2008VideoconferenceNicolas GEFFROY 4 Study of a new Hcal geometry… Examples of tilt level as a function of the tangent circle radius R circle Є [ 0; 1420mm] with R int _barrel = 1420mm Classical geometry R circle = 0 ( R min ) R circle = 600 R circle = 1000 R circle = 1420 ( R max ) - 1 st version -
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24/01/2008VideoconferenceNicolas GEFFROY 5 Study of a new Hcal geometry… In order to avoid cracks, the edges should not point to the center of the barrel Proposal of a second tilted geometry Second version : The 2 edges of a module are tangent to a circle, in an opposite way The circle radius is the parameter which determinates the tilt level - 2 nd version - Symmetric geometry
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24/01/2008VideoconferenceNicolas GEFFROY 6 Study of a new Hcal geometry… Examples of tilt level as a function of the tangent circle radius Classical geometry R circle = 0 ( R min ) R circle = 150 R circle ≈ 380 (= module’s width / 2) R circle = 500 Specific configuration - 2 nd version -
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24/01/2008VideoconferenceNicolas GEFFROY 7 Study of a new Hcal geometry… 2 types of modules: 6 rectangles 6 trapezoids Space for fixation devices - 2 nd version - Specific configuration : R circle = module’s width / 2 4.λ i Overall dimensions given by the fixation of whole system !
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24/01/2008VideoconferenceNicolas GEFFROY 8 Study of a new Hcal geometry… 12 Modules’ bottom : same dimensions Easy integration of Ecal (see Marco Oriunno’s presentations) No cracks crossing (neither in EMcal nor in Hcal) - 2 nd version -
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24/01/2008VideoconferenceNicolas GEFFROY 9 Study of a new Hcal/EMcal assembly… Assembly of a module: use of stringers Assembly of a module with the others Assembly of EMcal wedges with Hcal: use of rails (see Marco’s presentation) - 2 nd version - Fixation of the whole structure (3h & 9h)
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24/01/2008VideoconferenceNicolas GEFFROY 10 Proposal of Hcal assembly Detail of 2 modules Detection layer Steel interaction plate Stairs shape Objective : to fix the steel plates together to obtain a structure in which the detection layers can be inserted (like drawers).
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24/01/2008VideoconferenceNicolas GEFFROY 11 Proposal of Hcal assembly Detail of a detection layer Steel interaction plate A detection layer (“sandwich part”) consists in a chamber rigidified with two thin steel plates. Thin steel plates Chamber Detection layer Protection and stiffness !
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24/01/2008VideoconferenceNicolas GEFFROY 12 Proposal of Hcal assembly Detail of a module assembly Using of several stringers along the modules to fix the steel interaction plates together Complementary shapes
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24/01/2008VideoconferenceNicolas GEFFROY 13 Proposal of Hcal assembly Detail of a module assembly Stringers are welded on the both sides, all along the length, on interaction plates (to screw is possible as well ! ) In red : welding localization
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24/01/2008VideoconferenceNicolas GEFFROY 14 Proposal of Hcal assembly Each module is thus a stiff structure in which chambers can be inserted Several stringers are welded along the module left-shifted stringer right-shifted stringer
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24/01/2008VideoconferenceNicolas GEFFROY 15 Proposal of Hcal assembly The space between 2 consecutive stringers is for the stringer of the following module (quincunx assembly) NB : Radial mounting… All the volume between two consecutive modules is filled with steel stringers No “air” gaps !
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24/01/2008VideoconferenceNicolas GEFFROY 16 Proposal of Hcal assembly Inter-modules fixation: 2 small plates are screwed on blue and red stringers.
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24/01/2008VideoconferenceNicolas GEFFROY 17 Ecal fixation Proposal of Hcal assembly Ecal = 12 independent modules (in green) every Ecal module slides in Hcal thanks to rails (in orange)
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24/01/2008VideoconferenceNicolas GEFFROY 18 Proposal of Hcal assembly The whole system (Hcal & Ecal) slides inside the magnet thanks to rails. Part fixed on the cryogenic structure 3h & 9h fixation
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24/01/2008VideoconferenceNicolas GEFFROY 19 Proposal of Hcal assembly Global view of the structure
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24/01/2008VideoconferenceNicolas GEFFROY 20 Prospectives Perform Finite Element Analyses (FEA) : Computations of displacements/stresses of the structure check stresses near the fixation locations: Fixation of the Ecal modules on the base of Hcal modules. Fixation of the whole structure on the cryogenic magnet. check displacements of the structure : displacements of the modules with respect to the beam axis. displacements of the interaction plates (sufficient margin between 2 consecutives interaction plates to insert chamber). Optimization of the stringers thickness (= maximization of the size of the chambers)
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24/01/2008VideoconferenceNicolas GEFFROY 21 Prospectives Hcal & Ecal divided into 16 modules Other configuration :
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24/01/2008VideoconferenceNicolas GEFFROY 22 Prospectives 16 modules configuration : Hcal structure still symmetric Drawback : 16 spaces without detection (+4) Advantages : Smaller modules = smaller interaction plates & chambers Stiffer modules (less problem of flexion) Thinner stringers (smaller spaces without detection) Lighter modules (manoeuvrability) Reduction of loads (force & torque) on each Hcal module (due to Ecal modules)
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24/01/2008VideoconferenceNicolas GEFFROY 23 Conclusions Physic simulation is necessary to optimize the mechanics Several designs of Hcal are possible to avoid cracks Finite Element Analyses will be performed to confirm the feasibility of such designs
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