X-Ray Survey of The ATLAS SCT

The ATLAS Semi-Conductor Tracker

Alignment Techniques  Initial X-Ray Survey  Frequency Scanning Interferometry  Track-Based Alignment Procedures

Aims of The X-Ray Survey  Produce a map of the SCT modules  Calibrate the FSI system  Module positions can be inferred from shape of support structure  Provide a starting point for Track Alignment  Allows for much faster alignment parameter fixing

X-ray Survey Overview

The Scanning Head Optical strip reader Linear Motion BM250 Rotary Motion ADR200 X-Ray Assembly

R Measurement  Ø and Z fixed by scanning head  R found through use of stereo angle between X-Ray tubes

Linear Motion  8 pole induction motor  25:1 ratio gear box  Rubber Wheel Linear Motion BM250 Scanning Head BM250 motor Gear Box Rubber Wheel Rail

Optical Strip Reader  1.6m Long Scale Strip  RGH25 Read Head  RGB25 Signal Processor  Maximum Spatial resolution of 5μm Resolution 5μm Signal Period 20μm RGH25 Read Head

Laser System  Measures translations in X - Y plane and rotations in θ x or θ y  Cannot measure translations or rotations about the Z Axis  Yet to be installed on scanning head Beam Splitters Laser Beam CCD

Tilt Sensors  Measure rotations in θ x and Ø  Commercial read out electronics exist but still need to be configured Z Axis Scanning Head Tilt Sensors X Axis

Software Drivers  Labview Drivers manage interface between PC and Motor Controller  Interaction with SCT Daq server through ‘baton exchange’ via samba  Scan Data stored on SCT Daq server X-Ray Scan Control Software

Calibration X-Ray Beam Optical Table SCT Module (In transport case) Z Axis

SCT Daq  Replica of set up currently used in clean room  Hardware + software has been configured and tested  Will be used to read out modules during calibration

Forward Scan θ SCT Forward Section Z Axis X-Ray Beam Scanning Head  No need to vary θ continuously, use 2 or 3 fixed angles and vary Z  Simpler and more cost effective  Recent simulation indicates improved accuracy

Summary  Positioning System is now functional  Motor and Optical strip reader properly configured  Software drivers written  Laser and Tilt Systems still to be installed on Scanning Head  Currently assembling hardware required for calibration