Yury Gavrikov 25/03/2009 1

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 I met with two very nice g…oniometers 3 Because we decided to adapt their for a new experiment

Gear box Belt drive + “virtual” screw Engine DC-servo motor Carriage slides on the 2 guides 4

Inside of beam Outside of beam 5

 Angular movement 1mm Angule ~15mrad ~63mm Axis PusherPusher Angle Stepper motor & Belt drive Microscrew 6

Unificated solution for angular & linear motion: Stepper motor for driving LVDT for position measurement Common Control system for all devices It was needed the mashining of original parts 7

After modernization during last month before installation : - 4 revisions and full disassembling - A lot of motion tests and measurements - Fixing of sources of the problems 8

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 Digital Autocollimator specially designed for the experiment Range: ~ 8000  rad (horizontal) ~ 6500  rad (vertical) Resolution:< 0.5  rad 10

 The general Idea of angle measurement Mirror 11

 The Idea of crystal angle calibration Reference mirror Crystal 12

 Angle vs. LVDT position Goniometer 2Goniometer 1 13

Periodical structure corresponds to the motor revolution Nonlinearity : about +/- 50  rad 14

15 The goniometers are very SENSITIVE to any mechanical disturbance The design is SOFT. “Don’t touch” should be placed everywhere We can move it only in work direction to avoid all gaps  Mechanical stability

16  Stability of LVDT during 14 hours looks quite good (*) Gonio2, LVDT 3-5  rad (*) with averaging to reduce the noise

 Preliminary estimation for angular motion 17

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19 Crystal 1 Crystal 2 Ref. mirror

Digital autocollimator Reference mirror Laser 20 Penta prizm Viewport

Initial orientation of the alignment rail to the tank geometry +/- 350  rad Nonlinearity of goniometers +/- 50  rad 21

We can use this goniometers with some magic gestures right now BUT To reach better results in the future we have to develop a new goniometer 22