Hcal Geometry and Assembly

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

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… - 1st version - 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

4. Study of a new Hcal geometry… - 1st version - Examples of tilt level as a function of the tangent circle radius Rcircle Є [ 0; 1420mm] with Rint_barrel = 1420mm Rcircle = 0 ( Rmin ) Rcircle = 600 Rcircle = 1000 Classical geometry Rcircle = 1420 ( Rmax )

5. Study of a new Hcal geometry… - 2nd version - 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 Symmetric geometry

6. Study of a new Hcal geometry… - 2nd version - Examples of tilt level as a function of the tangent circle radius Specific configuration Rcircle = 0 ( Rmin ) Rcircle = 150 Rcircle ≈ 380 (= module’s width / 2) Classical geometry Rcircle = 500

7. Study of a new Hcal geometry… - 2nd version - Specific configuration : Rcircle = module’s width / 2 • 2 types of modules: • 6 rectangles • 6 trapezoids Space for fixation devices 4.λi Overall dimensions given by the fixation of whole system !

8. Study of a new Hcal geometry… - 2nd version - 12 Modules’ bottom : same dimensions Easy integration of Ecal (see Marco Oriunno’s presentations) No cracks crossing (neither in EMcal nor in Hcal)

9. Study of a new Hcal/EMcal assembly… - 2nd version - Assembly of a module: use of stringers Assembly of a module with the others Fixation of the whole structure (3h & 9h) Assembly of EMcal wedges with Hcal: use of rails (see Marco’s presentation)

10. 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).

11. Proposal of Hcal assembly Detail of a detection layer Thin steel plates Detection layer Steel interaction plate Chamber A detection layer (“sandwich part”) consists in a chamber rigidified with two thin steel plates. Protection and stiffness !

12. 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

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. Proposal of Hcal assembly Several stringers are welded along the module left-shifted stringer Each module is thus a stiff structure in which chambers can be inserted right-shifted stringer

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. Proposal of Hcal assembly 2 small plates are screwed on blue and red stringers. Inter-modules fixation:

17. Proposal of Hcal assembly Ecal = 12 independent modules (in green) every Ecal module slides in Hcal thanks to rails (in orange) Ecal fixation

18. Proposal of Hcal assembly Part fixed on the cryogenic structure 3h & 9h fixation The whole system (Hcal & Ecal) slides inside the magnet thanks to rails.

19. Proposal of Hcal assembly Global view of the structure

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. Prospectives Other configuration : Hcal & Ecal divided into 16 modules

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

23. Conclusions • Several designs of Hcal are possible to avoid cracks • Finite Element Analyses will be performed to confirm the feasibility of such designs Physic simulation is necessary to optimize the mechanics