IT Frame Survey. Detector Boxes Fiducialisation

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1 IT Frame Survey & Detector Boxes Fiducialisation 1

IT Frame Survey Coordinate System (1) The origin of the Survey coordinate system is at the Interaction Point (IP) Correction of the nominal z values : z = znominal - tan(0.

2 IT Frame Survey Coordinate System (1) The origin of the Survey coordinate system is at the Interaction Point (IP) Correction of the nominal z values : z = znominal - tan( ) x 6 half-frames to be surveyed ITA/C Survey coordinate system Z (SU) vertical X (SU) horizontal IP LHC Nom ea in a l B ne m Li IT3A IT2A IT1A IT Frames IT3C IT2C IT1C ~6m Towards pit 1 (ATLAS) mrad horizontal LHCb coordinate system Towards pit 7 Y (SU) horizontal Towards LHC centre y ~3.7m z x 2

3 IT Frame preliminary results (2) First IT «Geometrical Controls» (Local coordinate system) and Adjustments (Survey coordinate system) realized from the magnet area by a triangulation method (theodolite): IT1C (Oct.18 th 06, //edms.cern.ch/document/ Geometrical Control ) IT2C (Nov. 9 th 06, //edms.cern.ch/document/ Geometrical Control ) IT1C IT2C IT3A (Jan.26 th 07, //edms.cern.ch/document/ Before Adjustment ) (Feb. 1 st 07, //edms.cern.ch/document/ After Adjustment ) IT3C (Dec. 5 th 06, //edms.cern.ch/document/ Geometrical Control ) (Feb. 2 nd 07, //edms.cern.ch/document/ Before Adjustment ) Due to Beam Pipe UX85 2 & 3 (and protections) installation, no access to magnet area possible any more : New strategy for IT Survey (2 steps) 1) Frame survey measurements in Opened position 2) Frame survey measurements in Closed position 3

Take ~150 photographs of the frame in opened position, which contains permanent coded photo targets (20) recognized by the system.

4 Survey in opened position : Photogrammetry (3) Theodolite measurements of fiducial marks give the global scale in almost closed position. Take ~150 photographs of the frame in opened position, which contains permanent coded photo targets (20) recognized by the system. Photogrammetric targets are used as a reference for the IT detector boxes positions. Complete E frame geometry on precision rails obtained by the transformation of the coordinates in opened position to the coordinates in almost closed position (with a best fit 3D ). 4

Survey in opened position (4) F6 View from IP : 474

484 485 486 CB Coded targets F3 Fiducial marks

5 Survey in opened position (4) F6 View from IP : F7 F5 35mm CBR 150mm 35mm 35mm 481 CTL thickness=0.12mm thickness=0.12mm TT_L F4 482 CBL CTR CBR TT_R TB_L TB_R 483 CT CB Coded targets F3 Fiducial marks Photogrammetric targets z 487 CTR y TB_L x F F1 TB_R 5

6 IT Frame Survey : Results (5) IT1A (March 30 th 07) IT2A (April 19 th 07) IT1A D x (mm) D z (mm) IT2A D x (mm) D z (mm) F F F F F F F F F F F F F F CT CT CT_L CT_L CT_R CT_R CB CB CB_L CB_L CB_R CB_R The most important CT_L/R and CB_L/R targets positions are adjusted thanks to crenels on the brackets. 6

7 Survey in closed position (6) Theodolite method for the targets on the IT detector boxes and some accessible targets on the E frames. Final measured positions of the IT detector boxes. Possible to make the measurements from the outside of the magnet in the RICH1 region. 7

ch/document/790654 Precision obtained during the test at 1σ level is 0.05mm and 0.1mrad on the angles.

8 IT box Fiducialisation 12 IT detector boxes to be fiducialised. IT detector box fiducialisation test performed on Oct. 25 th -26 th Precision obtained during the test at 1σ level is 0.05mm and 0.1mrad on the angles. Needs for fiducialisation : Rotating support for the box Movable neon lights to ease the measurements of the detector crosses Table stability (improved with long diagonal bars) 8

9 IT Boxes Offsets in ConDB y (vertical) dx Nominal positions dy β z (along beam) x (horizontal) α Measured positions γ dz Offset : dpos Additional targets Rotation : drotαβγ 9

10 IT sensors Offsets in ConDB Offset : dpos Rotation : drotαβγ y x z 142 γ α β Measured positions Nominal positions 10

11 Survey Timescale Frame Survey in Opened Position : IT3A and ITC : IT3A survey is forseen on Thursday 24 th of May. The ITC photogrammetric measurements should be finished up to mid-july. Frame Survey in Closed Position : All IT frames : Depends on when the IT detector boxes will be finished and when the beam pipe protection will be removed. IT Detector Box Fiducialisation : All IT boxes : The Fiducialisation of the first IT detector box is forseen tomorrow in the clean room at CERN! 11

Variation of Refractive Index inside an Aerogel Block

$Variation of Refractive Index inside an Aerogel Block$ Università degli Studi di Milano Bicocca Variation of Refractive Index inside an Aerogel Block Davide Perego RICH MEETING - CERN - April 21 st 2004 Introduction The Refractive Index of aerogel and its