1. Hcal Geometry and Assembly Videoconference January 2008, 24th

2. 24/01/2008VideoconferenceNicolas GEFFROY 2 Study of a new Hcal geometry… …motivation: « cracks » in the calorimeter Classical geometry ( muons are lost, hadrons ? )

3. 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 -

4. 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 -

5. 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

6. 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 -

7. 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 !

8. 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 -

9. 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)

10. 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).

11. 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 !

12. 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

13. 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

14. 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

15. 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 !

16. 24/01/2008VideoconferenceNicolas GEFFROY 16 Proposal of Hcal assembly Inter-modules fixation: 2 small plates are screwed on blue and red stringers.

17. 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)

18. 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

19. 24/01/2008VideoconferenceNicolas GEFFROY 19 Proposal of Hcal assembly Global view of the structure

20. 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)

21. 24/01/2008VideoconferenceNicolas GEFFROY 21 Prospectives Hcal & Ecal divided into 16 modules Other configuration :

22. 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)

23. 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