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Hcal Geometry and Assembly

Hcal Geometry and Assembly. CLIC Meeting - LAPP December 2008, 15th. Study of a new Hcal geometry…. …motivation: « cracks » in the calorimeter. ( muons are lost, hadrons ? ). Classical geometry. Study of a new Hcal geometry…. Projective configuration. Tilted configuration.

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Hcal Geometry and Assembly

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  1. Hcal Geometry and Assembly CLIC Meeting - LAPP December 2008, 15th

  2. Study of a new Hcal geometry… …motivation: « cracks » in the calorimeter ( muons are lost, hadrons ? ) Classical geometry

  3. Study of a new Hcal geometry… Projective configuration Tilted configuration Same internal & external boundaries (2 regular dodecagons)

  4. Proposal of Hcal assembly Detail of 2 modules Detection layer Stairs shape Steel interaction plate Objective : to fix the steel plates together to obtain a structure in which the detection layers can be inserted (like drawers).

  5. Proposal of Hcal assembly Complementary shapes Detail of a module assembly Using of several stringers along the modules to fix the steel interaction plates together

  6. Study of a new Hcal assembly… Left-shifted stringers Right-shifted stringers

  7. Proposal of Hcal assembly Shifted stringersGain of volume / No “air” gap

  8. Study of a new Hcal assembly… To realize a belt to fix the modules together thanks to screws Belt Possibility of multiple belts along the length of the barrel ! NB: Belt maybe out of scale… Drawback : increase of the overall dimension

  9. Study of a new Hcal assembly… Cf. DELPHI Possibility of several belts along the barrel, whose shapes could be full rectangular, or I profile, etc… Cf. Atlas experiment

  10. Study of a new Hcal assembly… Integration with ECAL No crack in the 2 detectors

  11. Study of a new Hcal assembly… 3D view

  12. Study of the Hcal forward Face view Top view

  13. Study of the Hcal forward Top view Beam axis Only absorbers are represented Minimize the space betwwen the 2 absorbers of the same plane

  14. Study of the Hcal forward Assembly procedure The first 2 absorbers are fixed on the muon detector Muons detector Counterbored holes in spacers (blue parts) Blue parts are screwed on absorbers Their thicknesses are the same than the ones of chambers, i.e. 8 mm ! The following absorbers are screwed on the blue parts

  15. Study of the Hcal forward Chambers insertion Planes of the blue parts are non projective No crack in the Hcal end-cap

  16. Study of the Hcal forward Inserted from the left Inserted from the right

  17. Study of the Hcal forward Chambers insertion 3D view

  18. Prospects 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)

  19. Prospects NB : absorber thickness depends on the number of layers: 40 layers in this case ! Hcal made of Tungsten will be obviously more expensive than using Stainless Steel. Nevertheless it drastically reduces the cost of the solenoid and the muon system ! OPTIMIZATION (need for physic simulation…)

  20. Prospects Other configuration : Hcal & Ecal divided into 16 modules

  21. Last comments • The Hcal modules are not projective, but internal cracks can appear (due to bad layout of chambers). • The modules must be fixed together, the Hcal has to be inserted and fixed inside the coil. Spaces / clearances for Mechanics (and services) must be taken into account ! The external radius of the Hcal is NOT given by the circle which passes through the tip of the last chamber… To take into consideration in Physics simulation !!!

  22. Prospects 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) Lighter modules (manoeuvrability) Thinner stringers (smaller spaces without detection) Reduction of loads (force & torque) on each Hcal module (due to Ecal modules)

  23. Study of a new Hcal assembly… Wouldn’t it be possible to put locking devices at 5 & 7 o’clock ? DELPHI • Maybe more simple parts at 5&7 o’clock than 3&9 o’clock (compression and no torque…no flexion!) • Maybe a great benefit considering the overall dimension (magnet internal radius)

  24. Study of a new Hcal assembly… Wouldn’t it be possible to put fixation devices at 5 & 7 o’clock ? Case of a fixation at 3 o’clock : Parts really under-estimated (because of torques, etc…) Parts under compression Minimal magnet internal radius ???

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