1. 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 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

2. TPC meeting, Sardinia, 16-17 May 2004Børge Svane Nielsen, NBI2 Laser system principle

3. TPC meeting, Sardinia, 16-17 May 2004Børge Svane Nielsen, NBI3 Rod gluing and installation 1.Drill holes in short rods: done 2.Mount mirror bundles in support rings: done 3.Glue mirror support rings onto short rods: done 4. 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 7.Re-measurements with TPC in final orientation

4. TPC meeting, Sardinia, 16-17 May 2004Børge Svane Nielsen, NBI4 Full length rod gluing All angle measurements recorded for construction database Rods with pre-mounted laser mirrors were glued to full length TPC rods, using green laser fitted with telescope to produce 20 mm beam for precise alignment and angle measurements

5. TPC meeting, Sardinia, 16-17 May 2004Børge Svane Nielsen, NBI5 Green laser assembly 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 TPC end plate

6. TPC meeting, Sardinia, 16-17 May 2004Børge Svane Nielsen, NBI6 Laser rod installation Installation and re-measurements of all angles of central laser rays inside TPC field cage before strip mounting after strip mounting Green laser beam

7. TPC meeting, Sardinia, 16-17 May 2004Børge Svane Nielsen, NBI7 Spots measurements in TPC field cage 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 mounting of outer mylar strips. Difference before/after strip mounting: - large, systematic deviations in z - smaller deviations in 

8. TPC meeting, Sardinia, 16-17 May 2004Børge Svane Nielsen, NBI8 Bending of rods Michi: bending of rod in the middle between supports due to strips: f (mm) = (Q L 3 ) / (384 E J), J=π/64 ( D 4 – d 4 ) Original parameters (L=21 cm): f = 0.003 mm  dZ (1.7m)=0.02 mm Half number of supports (L=42 cm): f = 0.047 mm  dZ (1.7m)=0.38 mm Final 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)

9. TPC meeting, Sardinia, 16-17 May 2004Børge Svane Nielsen, NBI9 Status of quartz optics and mechanics  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 splitter assembly Bending prism assembly Safety tube

10. TPC meeting, Sardinia, 16-17 May 2004Børge Svane Nielsen, NBI10 3d CAD drawings of full system on endplates CAD drawings transmitted to GSI

11. TPC meeting, Sardinia, 16-17 May 2004Børge Svane Nielsen, NBI11

12. TPC meeting, Sardinia, 16-17 May 2004Børge Svane Nielsen, NBI12

13. TPC meeting, Sardinia, 16-17 May 2004Børge Svane Nielsen, NBI13 Decision taken on beam height over endplates 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 rods Laser tube must pass over TPC feet  H  113 mm Chosen H = 113 mm  height of top of last beam splitter box = 192 mm i.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”) Need this info into CAD drawings at GSI H

14. TPC meeting, Sardinia, 16-17 May 2004Børge Svane Nielsen, NBI14 Displacement of prism near TPC feet Agreement with Y.Andres to displace 2 prisms on each endcap, to avoid hitting the TPC ’feet’

15. TPC meeting, Sardinia, 16-17 May 2004Børge Svane Nielsen, NBI15 DCS discussions 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 Work has starting at GSI.