Mechanical design of the Roman pots
Status report
M.Oriunno
Common project with EST Division
(L.Favre, G.Laurent and R.Perret)
Conceptual Design of the Roman Pot is made of on three main steps:
Design of the pot
Design of the Roman Pot Station
Integration in the Tunnel
What has been done for the pot:
Secondary Vacuum Pot
Mechanical Simulation and Optimization of the thin window (Inconel 0.1mm)
Integration of detectors inside the pot with the hypothesis of capillary cooling
Design of flange to routing the detector’s services outside the pot
Welding on a flat foil and folding
Inconel 718
Inconel 600
SSTEEL 316
What has been done for the Roman pot system:
Two solutions have been designed:
Symmetric distribution of the loads but less favorable access for maintenance
Not symmetric loads but optimized access
For Both solutions
A compensation system linked to the primary vacuum allows for a fine regulation but an independent vacuum system can be still implemented
A capacitive system accounting the relative position of the top-bottom pots,
Integration of two Roman Pot stations between the TAN and D2
Pot
Lever Arm
Capacitive sensor
Compensation bellow
Racks
TAN
Collimator
BPMQLR
What must be done on the pot design:
Production of 5 pot prototypes to test under vacuum the welding technology of the thin window (June 2003)
Pot Prototype for RF Pick up test on electronics
Production of a mock-up of the pot with dummy detectors to have a full integration exercise with the services (June 2003)
Open issues:
Cryogenic Cooling System: Capillary local cooling, Cold fingers. Very unlikely we can spill cryogens from the machine or CMS. LHC/ECR group is working on that.
Electronic RF pickup shielding: are there special constraints on the window ?
Do we have to bake out the pot at 200oC ?
•Yes -> a thin window can not stand the thermal stress
•No -> a locally increased dynamic pressure of residual gases must be accepted
Constraints from the LHC-Vacuum group :
The compensation of the forces must not be relied on a pick up of the primary vacuum
Since all the vacuum chamber in the LSS are NEG coated, the pot must be designed to stand a baked out up to 300oC
A risk analysis of the operation of the detector operation should be performed
A design pressure of at least 1.5 bar shall be considered in the design of the window. A rupture disk breaking at a differential pressure of <0.5 bars should be installed
Roman Pots’ Chapter in the TDR
Pot Design : Integration study, Simulation and Prototype test results
Cooling System: Capillaries or Cold finger
Roman Pots Station design: precision, stability, vacuum and accessibility
Integration in the Tunnel: Space allocation, services and radiation environment
We are ready to write an exhaustive chapter !!