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

2. Clic meeting - 15/12/2008 Nicolas Geffroy 2 Study of a new Hcal geometry… …motivation: « cracks » in the calorimeter Classical geometry ( muons are lost, hadrons ? )

3. Clic meeting - 15/12/2008 Nicolas Geffroy 3 Study of a new Hcal geometry… Same internal & external boundaries (2 regular dodecagons) Projective configurationTilted configuration

4. Clic meeting - 15/12/2008 Nicolas Geffroy 4 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).

5. Clic meeting - 15/12/2008 Nicolas Geffroy 5 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

6. Clic meeting - 15/12/2008 Nicolas Geffroy 6 Study of a new Hcal assembly… Left-shifted stringers Right-shifted stringers

7. Clic meeting - 15/12/2008 Nicolas Geffroy 7 Proposal of Hcal assembly Shifted stringersGain of volume / No “air” gap

8. Clic meeting - 15/12/2008 Nicolas Geffroy 8 Study of a new Hcal assembly… To realize a belt to fix the modules together thanks to screws Possibility of multiple belts along the length of the barrel ! NB: Belt maybe out of scale… Drawback : increase of the overall dimension Belt

9. Clic meeting - 15/12/2008 Nicolas Geffroy 9 Study of a new Hcal assembly… Possibility of several belts along the barrel, whose shapes could be full rectangular, or I profile, etc… Cf. Atlas experiment Cf. DELPHI

10. Clic meeting - 15/12/2008 Nicolas Geffroy 10 Study of a new Hcal assembly… Integration with ECAL No crack in the 2 detectors

11. Clic meeting - 15/12/2008 Nicolas Geffroy 11 Study of a new Hcal assembly… 3D view

12. Clic meeting - 15/12/2008 Nicolas Geffroy 12 Study of the Hcal forward Face view Top view

13. Clic meeting - 15/12/2008 Nicolas Geffroy 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. Clic meeting - 15/12/2008 Nicolas Geffroy 14 Study of the Hcal forward Assembly procedure Muons detector The first 2 absorbers are fixed on the muon detector 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 Counterbored holes in spacers (blue parts)

15. Clic meeting - 15/12/2008 Nicolas Geffroy 15 Study of the Hcal forward Chambers insertion No crack in the Hcal end-cap Planes of the blue parts are non projective

16. Clic meeting - 15/12/2008 Nicolas Geffroy 16 Study of the Hcal forward Inserted from the left Inserted from the right

17. Clic meeting - 15/12/2008 Nicolas Geffroy 17 Study of the Hcal forward Chambers insertion 3D view

18. Clic meeting - 15/12/2008 Nicolas Geffroy 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. Clic meeting - 15/12/2008 Nicolas Geffroy 19 Prospects TungstenStainless Steel Absorption length λ (mm)95.855167.598 4.5 x λ (mm)431.3754.2 Absorber thickness (mm)10.818.9 1 layer thickness (mm)18.826.9 Calorimeter thickness (mm)7521076 External radius (mm)22472583 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. Clic meeting - 15/12/2008 Nicolas Geffroy 20 Prospects Hcal & Ecal divided into 16 modules Other configuration :

21. Clic meeting - 15/12/2008 Nicolas Geffroy 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. Clic meeting - 15/12/2008 Nicolas Geffroy 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) Thinner stringers (smaller spaces without detection) Lighter modules (manoeuvrability) Reduction of loads (force & torque) on each Hcal module (due to Ecal modules)

23. Clic meeting - 15/12/2008 Nicolas Geffroy 23 Study of a new Hcal assembly… Wouldn’t it be possible to put locking devices at 5 & 7 o’clock ?  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) DELPHI

24. Clic meeting - 15/12/2008 Nicolas Geffroy 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 ???