Calibration of clinometers for the alignment of muon chambers in the CMS experiment. Thomas MOSCHOUTIS, Marion RIPERT and Georgia KARAGIORGI with Dr HOHLMANN and Dr CARAWAY Florida Academy of Science – F.S.U., Tampa, 18 Mars 2005

Global view of the Compact Muon Solenoid

View of one Disk Dual-axis clinometers for monitoring orientation of transfer pates:

Calibration bench CIinometer sensing Liquid calibrated Linear mover Θ

Error calculation Error in φ: –φ =Tan -1 (L/H) –σ φ =(∂φ/∂L)*σ L +(∂φ/∂H)*σ H =(1/(L+H))*σ L -2L/(H 2 +H*L)*σ H Using the same formula: –σ Ω =(1/(L+M))*σ L -2L/(M 2 +M*L)*σ M Taking ρ=cos-1(M/K) and M→0 –σ ρ =σ M /K So the total error is: –σ θ =(σ φ 2 +σ Ω 2 +σ ρ 2 ) 1/2 M K ρ φ L H

First test curve

Zero degree measurement Pendulum clinometer Long rod to get more precision

Problem induced by the plate thickness

Second test curve

The 6 different mounting plates Clinometer’s place

Next setup Linear mover Adapter Tilting base Mounting plate

Adaptable base plate

Laser 0 degree measurement Tube filled with colored water Plane that needs to be horizontal (with a mirror fixed perpendicularly) Rotary laser level Mirror Laser beam Above viewSide view of the installation

Sensor Response vs. Angle theta

References CERN web page: Dr HOLMANN web page: FIT PSS web site: