hcal geometry and assembly clic meeting - lapp december 2008, 15th
Post on 01-Jan-2016
217 Views
Preview:
TRANSCRIPT
Hcal
Geometry and Assembly
CLIC Meeting - LAPP
December 2008, 15th
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 ? )
Clic meeting - 15/12/2008 Nicolas Geffroy 3
Study of a new Hcal geometry…
Same internal & external boundaries (2 regular dodecagons)
Projective configuration Tilted configuration
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).
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
Clic meeting - 15/12/2008 Nicolas Geffroy 6
Study of a new Hcal assembly…
Left-shifted stringers
Right-shifted stringers
Clic meeting - 15/12/2008 Nicolas Geffroy 7
Proposal of Hcal assembly
Shifted stringers Gain of volume / No “air” gap
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
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
Clic meeting - 15/12/2008 Nicolas Geffroy 10
Study of a new Hcal assembly…
Integration with ECAL
No crack in the 2
detectors
Clic meeting - 15/12/2008 Nicolas Geffroy 11
Study of a new Hcal assembly…
3D view
Clic meeting - 15/12/2008 Nicolas Geffroy 12
Study of the Hcal forward
Face viewTop view
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
Clic meeting - 15/12/2008 Nicolas Geffroy 14
Study of the Hcal forwardAssembly 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)
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
Clic meeting - 15/12/2008 Nicolas Geffroy 16
Study of the Hcal forward
Inserted from the left
Inserted from the right
Clic meeting - 15/12/2008 Nicolas Geffroy 17
Study of the Hcal forward
Chambers insertion
3D view
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)
Clic meeting - 15/12/2008 Nicolas Geffroy 19
Prospects
Tungsten Stainless Steel
Absorption length λ (mm) 95.855 167.598
4.5 x λ (mm) 431.3 754.2
Absorber thickness (mm) 10.8 18.9
1 layer thickness (mm) 18.8 26.9
Calorimeter thickness (mm) 752 1076
External radius (mm) 2247 2583
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…)
Clic meeting - 15/12/2008 Nicolas Geffroy 20
Prospects
Hcal & Ecal divided into 16 modules
Other configuration :
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 !!!
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)
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
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 compressionMinimal magnet internal radius ???
top related