TPC meeting, Sardinia, 16-17 May 2004 Børge Svane Nielsen, NBI 1 Status of laser system TPC meeting, Sardinia, 16-17 May 2004 Børge Svane Nielsen Niels Bohr Institute Work and developments since October 2003: Assembly of full length laser rods Rod installation and measurements Status of quartz optics Status of mechanics Placement of equipment on the endplates DCS discussions
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TPC meeting, Sardinia, 16-17 May 2004Børge Svane Nielsen, NBI1 Status of laser system TPC meeting, Sardinia, 16-17 May 2004 Børge Svane Nielsen Niels Bohr.
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TPC meeting, Sardinia, 16-17 May 2004Børge Svane Nielsen
Niels Bohr Institute
Work and developments since October 2003: Assembly of full length laser rods Rod installation and measurements Status of quartz optics Status of mechanics Placement of equipment on the endplates DCS discussions
Rod gluing and installationRod gluing and installation
1. Drill holes in short rods: done2. Mount mirror bundles in support rings: done3. Glue mirror support rings onto short rods: done4. Glue short rods into full length rods at CERN. done Scheduled to commence 20 October. alignment fixed during gluing, using green laser
5. Angle measurements on final rod possible in lab at CERN before installation, using same green laser done
6. Angle measurements possible again during rod installation in field cage, using same green laser done
All angle measurements recorded for construction database
Rods with pre-mounted laser mirrors were glued to full length TPC rods, usinggreen laser fitted with telescope to produce 20 mm beamfor precise alignment and angle measurements
Green laser has been fitted with telescope to produce 20 mm beam was used for full length rod gluing and (with 90 prism) for installation of rods in FC should be used again to re-measure angles with horizontal TPC
After installation in the TPC,the central narrow laser beam spots were measured relative to the inner rods (dR=1.7 m).Measured before/after mountingof outer mylar strips.
Difference before/after stripmounting:- large, systematic deviations in z- smaller deviations in
Michi: bending of rod in the middle between supports due to strips: f (mm) = (Q L3) / (384 E J), J=π/64 ( D4 – d4 )
Original parameters (L=21 cm): f = 0.003 mm dZ (1.7m)=0.02 mmHalf number of supports (L=42 cm): f = 0.047 mm dZ (1.7m)=0.38 mmFinal macrolon tube dim. (L=42 cm): f = 0.079 mm dZ (1.7m)=0.64 mm
Looks consistent with measurements of mirror bundle 2 and 3,but clearly much worse for mirror bundles 1 and 4 ( 5 mm)
Quartz components (prisms, beam splitters, mirrors etc) for end-plates and laser hut received and tested
needed coating re-work at factory: imminent re-delivery Design progressing on opto-mechanical supports on end-plates Production of prism assemblies ongoing in NBI workshop Beam splitter holders bought and ready
Beam moves ”up” (away from endplate)by 4 mm at each beam splitter (2 times)
Minimum beam height over endplate is H=90 mm, due to flanges with rodsLaser tube must pass over TPC feet H 113 mm Chosen H = 113 mm height of top of last beam splitter box = 192 mmi.e. full height (200 mm) up to SSW needed at splitter (and prism) boxes; upper part of the tube is about 135 mm from endplates (65 mm ”left”)
DCS:• laser remote control: Spectron ’standard’ communication• 3-axis adjusters control: New Focus iPico system• cameras: USB web cameras (like ITS alignment) Collaboration with D. Beck (GSI) and M.Cherney (Creighton U):• looking into equipment sensitivity of magnetic field and radiation• drivers for laser and 3-axis adjusters to be written for PVSII• LabVIEW interface to USB cameras, with pictures and parameters communicated to PVSII through DIM or shared files• Operator or automatic beam steering in PVSII script