BGC mechanical design JOI NT SKIMMER AND NO
BGC mechanical design JOI NT SKIMMER AND NO ZZLE C HAMBER OPTIC AL RE SOL U TIO N TARG ET NOZZLES 19 July 2019 BGC MECHANICAL DESIGN - JOHANNA GLUTTING 1
Joint skimmer and nozzle chamber - Reduction of the total length by the thickness of two vacuum flanges + space for screws - Prealigned skimmer assembly can be “pluged in” - Internal connections are made with bellows with spring characteristics 19 July 2019 BGC MECHANICAL DESIGN - JOHANNA GLUTTING 2
Skimmer assembly • Skimmer adapters can easily be changed to alter the distances • Bellows with spring characteristics separate the volumes • Green: before and after the first skimmer • Blue: before and after the second skimmer (several solutions possible instead of blue bellow) 19 July 2019 BGC MECHANICAL DESIGN - JOHANNA GLUTTING 3
Nozzle position in the different versions V 2 (Cockcroft): 575 mm (without spacer chamber, from 3 D model) 775 mm (with spacer chamber) V 3 (LHC demonstrator): 390 mm ≈ 350 mm min. possible (requires redesign) ≈ 520 mm max. possible (before getting too close to the transport zone) one nozzle position must be chosen skimmer distances can be changed easily (≈ 20 mm range) new skimmer adapters 19 July 2019 BGC MECHANICAL DESIGN - JOHANNA GLUTTING 4
Optical resolution and position target 19 July 2019 BGC MECHANICAL DESIGN - JOHANNA GLUTTING 5
Linear bellow drive assembly 19 July 2019 BGC MECHANICAL DESIGN - JOHANNA GLUTTING 6
Optical target manufacture - Blacken with chromium oxide - Machining of the target pattern - Two companies have been asked if they can do the machining of the pattern (Vuichard and RAL) - Both would like to do tests on samples (electro erosion) - No price inquiry yet 19 July 2019 BGC MECHANICAL DESIGN - JOHANNA GLUTTING 7
Nozzle progress - Dimensions of the flat divergent nozzle - Alignment strategy - Convergent divergent nozzle 19 July 2019 BGC MECHANICAL DESIGN - JOHANNA GLUTTING 8
Dimensions of the flat divergent nozzle Drawing Measurement - focus on throat and exit Dimensions 0. 06 and 0. 607 mm - Distance between the focal planes Dimension 3. 3 mm (3. 1 with callipers) 19 July 2019 BGC MECHANICAL DESIGN - JOHANNA GLUTTING 9
Alignment with a divergent part Adjustment of the laser angle until it is in the centre of the nozzle outlet Same procedure for CD nozzles and for flat -divergent nozzles 19 July 2019 BGC MECHANICAL DESIGN - JOHANNA GLUTTING 10
Alignment test: - When rotating the nozzle the laser spot does not stay in position relative to the outlet - The nozzle axis is not parallel to the rotation axis = axis of the guide part Rotation and translation axis - Measurements show that the angle deviation is between 0. 4° and 0. 5° (tested with different holders) ≈ 5 mm in the interaction point Align everything to the axis of the nozzle or to theoretical axis? Make a holder to equalize the 0. 5°? 19 July 2019 BGC MECHANICAL DESIGN - JOHANNA GLUTTING Centre of the outlet Axis of divergent part Centre of the laser 11
Consequences of angle error Nozzle position 2 Nozzle position 1 Alignment lost Aligned First skimmer Translation and rotation axis ≈18 um over 3 mm Move the nozzle away 19 July 2019 BGC MECHANICAL DESIGN - JOHANNA GLUTTING 12
CD nozzle Clear laser spot with focus on exit Clear focus on throat CD No clear spot in the plane of the exit No clear focus on the throat possible Much lower light intensity than with flat divergent The white left overs distort the image ? Left over burrs are removed Apply higher pressure ? 19 July 2019 BGC MECHANICAL DESIGN - JOHANNA GLUTTING Flat divergent 13
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