TPC meeting, Sardinia, 16-17 May 2004 Børge Svane Nielsen, NBI 1
Status of laser systemStatus of laser system
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
TPC meeting, Sardinia, 16-17 May 2004 Børge Svane Nielsen, NBI 2
Laser system principleLaser system principle
TPC meeting, Sardinia, 16-17 May 2004 Børge Svane Nielsen, NBI 3
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
7. Re-measurements with TPC in final orientation
TPC meeting, Sardinia, 16-17 May 2004 Børge Svane Nielsen, NBI 4
Full length rod gluingFull length rod gluing
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
TPC meeting, Sardinia, 16-17 May 2004 Børge Svane Nielsen, NBI 5
Green laser assemblyGreen 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
TPCend plate
TPC meeting, Sardinia, 16-17 May 2004 Børge Svane Nielsen, NBI 6
Laser rod installationLaser rod installationInstallation and re-measurements of all angles of central laser rays inside TPC field cage
before strip mounting
after strip mounting
Green laser beam
TPC meeting, Sardinia, 16-17 May 2004 Børge Svane Nielsen, NBI 7
Spots measurements in TPC field cage
Spots measurements in TPC field cage
Spot z movement due to strips
-6.0
-4.0
-2.0
0.0
2.0
4.0
6.0
8.0
1 5 9 13 17 21 25 29 33 37 41 45
Spot number (4 spots per rod)
Mo
vem
ent
(mm
)Spot Phi movement due to strips
-3.0
-2.0
-1.0
0.0
1.0
2.0
3.0
1 5 9 13 17 21 25 29 33 37 41 45
Spot number (4 spots per rod)
Mo
vem
ent
(mm
)
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
TPC meeting, Sardinia, 16-17 May 2004 Børge Svane Nielsen, NBI 8
Bending of rodsBending of rods
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)
TPC meeting, Sardinia, 16-17 May 2004 Børge Svane Nielsen, NBI 9
Status of quartz optics and mechanics
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 assemblyBending prism assembly
Safety tube
TPC meeting, Sardinia, 16-17 May 2004 Børge Svane Nielsen, NBI 10
3d CAD drawings of full system on endplates
3d CAD drawings of full system on endplates
CAD drawings transmitted to GSI
TPC meeting, Sardinia, 16-17 May 2004 Børge Svane Nielsen, NBI 11
TPC meeting, Sardinia, 16-17 May 2004 Børge Svane Nielsen, NBI 12
TPC meeting, Sardinia, 16-17 May 2004 Børge Svane Nielsen, NBI 13
Decision taken on beam height over endplates
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 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”)
Need this info into CAD drawings at GSI
H
TPC meeting, Sardinia, 16-17 May 2004 Børge Svane Nielsen, NBI 14
Displacement of prism near TPC feet
Displacement of prism near TPC feet
Agreement with Y.Andres to displace2 prisms on each endcap, to avoid hittingthe TPC ’feet’
TPC meeting, Sardinia, 16-17 May 2004 Børge Svane Nielsen, NBI 15
DCS discussionsDCS 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.