THE H8 TEST STAND Conceptual Design Mechanical supports Status of preparation Project schedule 1 (Brandeis, CERN, MPI, Seattle - presented by Sandro Palestini) March 17, 2001 Or: The Endcap Alignment test in the H8 Test-Beam Area

Conceptual Design S.Palestini 2 A proper model of the Endcap alignment is obtained in a octant, which on each station, includes: one sector of large chambers, and one of small chambers two alignment bars, with azimuthal (and radial) viewlines four polar viewlines (at least) two chambers with proximity alignment

Conceptual design S. Palestini 3 The alignment will be checked by: redundancy in optical measurements between bars using a muon simulator and phantom chambers equipped with alignment devices ( Phase I ) using beam and real chambers ( Phase II ) Implementation in the test beam: beam to simulate 15 deg stiff muons chamber stations oriented vertically

Test program Stability and consistency checks Check short/long term stability of the optical and temperature sensors Check intrinsic resolution of the sensors over long distances Check the alignment reconstruction software with real data Check contributes of the different sensors to the fit  2 (identify problems with sensors database and readout) Compare reconstructed sensor positions with the results of photogrammetry survey (300  m precision ?) Relative tests of the alignment system Use muon simulator on phantom chambers Move one bar in a controlled way along the “sagitta” direction and compare with the sensor readings Absolute tests of the alignment system Use redundancy of the alignment system: predict the reading of one polar sensor by using in the fit all the other sensors S. Palestini 4

Mechanical supports: EI S. Palestini 5 Design and built to be similar to 1/6 of ATLAS Small Wheel Could support CSCs and two rings of MDTs EIL1 and EIS1 to test alignment and intercept beam

Mechanical supports: EM 6 EM built as octant, by the same firm which is studying the Big Wheels (ISTC contract). EML2 and EMS2 used in test. Needs a large steel frame to hold it in position (design CERN SL/EA, being shipped) S. Palestini

Mechanical supports: EO 7 Made of two sectors which will hold chambers and bars (one for large and one for small chambers). EOL3 and EOS3 use in test. supported by a back structure S. Palestini

Status S. Palestini 8 Design of details (mechanics, alignment) near completion 4 out of 6 bars assembled, calibration in April-May Mechanical support completed in May Alignment, assembly of optical devices in May-June Read-out/analysis of optical devices being implemented in PVSS Test of alignment without beam to be performed in summer Possibility of test with real chambers and beam (Phase II) in October being discussed (otherwise in 2002)

Schedule ( * ) S. Palestini 9 ( * ) Maintaned by F. Cerutti

Schedule S. Palestini10

Final comment S. Palestini11 EMEM EOEO Barrel stand Endcap stand Barrel set-up side view A coherent test program (for ) is being evaluated by the collaboration (a muon system test ). It would add barrel MDTs to the H8 set-up. A complete test of one barrel alignment unit could be made