1. Paul Soler, 23June 2000 RAL and Univ. of Glasgow MONITORING, ALIGNMENT AND CONTROL OF THE RICH DETECTORS

2. Paul Soler, 23 June 2000 2 Contents TDR supporting document (so far) z1. Objectives z2. Gas Monitoring y2.1 Gas re-circulation system y2.2 Refractive index y2.3 Transparency of the gas z3. Mechanical Monitoring z4. Electronics Monitoring z5. Photon Detector Monitoring z6. Alignment y6.1 Survey of mirror and detector components y6.2 Alignment with data y6.3 Laser alignment system z7. Control Hardware and Software z8. Conclusions

3. Paul Soler, 23 June 2000 3 Gas Monitoring zMonitoring of O 2, H 2 O, P, T, cryogenic plant

4. Paul Soler, 23 June 2000 4 Refractive Index monitoring zRefractive index through speed of sound: v = ( RT/M) 1/2 zAbsolute n with Fabry-Perot:

5. Paul Soler, 23 June 2000 5 Other monitoring tasks zTransparency of gas: absorption with monochromator zMechanical monitoring: stability of supports with single mode fibres and semi-transparent Si sensors zElectronics monitoring: HV, LV, bias voltage, focusing voltage, leakage current, discriminators, test pulses Photon detector monitoring: light pulser for dead channels and QE( ).

6. Paul Soler, 23 June 2000 6 Alignment in RICH Detectors zExperimental aim: alignment to less than 0.1 mrad zProposed procedure: ySurvey mirrors and photon detectors in laboratory yInstall in support structure and survey in situ yHave laser alignment system for final adjustment of tilts and positions before closing the gas enclosure yContinue monitoring alignment with laser alignment system yFinal alignment by reconstructing Cherenkov rings with data

7. Paul Soler, 23 June 2000 7 Alignment with data zCompare difference in reconstructed tilt angles for unambiguous photons (F. Filthaud, 19 March 1999) c rec - c exp = A cos ( c - 0 ) zIf relative alignment ~ 0.5 mrad then alignment accuracy of 0.2 mrad (including mirror quality) can be achieved with data C C C C CHARGED PARTICLE Cherenkov Photon MIRROR x

8. Paul Soler, 23 June 2000 8 Laser alignment: optic fibres (or mirrors) zSingle mode fibres coupled to silicon laser (690 nm) zCollimating optics: Gaussian beam profile 2-3 mm over 10 m distance zUsed for laser alignment ATLAS muon system zAlternatively: mount optic fibres on mirrors zOr, use mirrors

9. Paul Soler, 23 June 2000 9 Control Hardware and Software

10. Paul Soler, 23 June 2000 10 Conclusions zFirst Draft of TDR Monitoring, Alignment and Control document finished: please make comments! zMonitoring tasks: yGas Monitoring (P,T,impurities) yRefractive index yTransparency yMonitoring mechanical stability yElectronics monitoring yPhoton Detector efficiencies, dead channels zAlignment ySurvey of mirror and detector components yAlignment with data yLaser alignment system zControl Hardware and Software