Optical Position Sensor for the VWS Tolerances and

Optical Position Sensor for the VWS Tolerances and possibilities Jose Luis Sirvent Jonathan Emery Student Meeting 12– February -2012

1. Transmission � Loss ◦ ◦ of -3 d. B: Horizontal plane: Disk-Fiber +-0. 25 mm Vertical plane: Fiber-Fiber misalignment 60 um Angular tolerance: 0. 5 deg Signal received ~ 0. 37%

1. Transmission � Signal appearance ◦ 30 Khz ◦ 0. 0422 m. Wpp

2. Reflection � Loss ◦ ◦ of -3 d. B: Horizontal plane: Disk-Fiber +- 0. 3 mm Vertical plane: Width of the slides Angular tolerance ~ +-2. 5 deg Signal received ~ 0. 58%

3. Focusing � 3. 1 Focuser with commercial components

3. Focusing � Loss ◦ ◦ ◦ of -3 d. B: Horizontal plane: Fiber-Lens 7 mm -+ 250 um Horizontal plane: Lens-Disk 2. 23 mm -+60 um (Too small? ) Vertical plane: Slits width Angular tolerance ~ +-2 deg Signal received ~ 11% (Improvement > Factor 10!!)

3. Focusing � Improvement ◦ ◦ ◦ of tolerances: Defocus Bigger spot size Horizontal Plane: Fiber - Lens 4. 29 mm +- ? Horizontal Plane: Lens – Disk 4. 35 mm +- 200 um Vertical plane ~ +-2 deg Signal received ~ 11% 4. 35 -+ 0. 2 mm

3. Focusing � Fit with sinusoid

4. Double Pattern (Work in progress)

5. Tolerances Table Focuser 800 m. Vpp Transmission (50 m. Vpp) Reflection (80 m. Vpp)

6. Emiters Receivers Analysis LASER DIODES Company OPTEK Component OPF 372 A Class Ga. AIAs LED Max Curr. 100 m. A Max Power (d. Bm) -10 Max Power (m. W) 0. 1 Stability Stable KYOSEMI KLD 085 VC VCSEC 12 m. A 1. 59 1. 44 LASER COMP PL 85 B 002 ST 83 -T-0 45 m. A 6. 98 5 Trans -34. 33 Ref -32. 35 Focus -19. 55 Stable -22. 74 -20. 76 -7. 96 Col - Noisy (Reflections) -17. 35 -15. 37 -2. 57 - Comment Last weeks PHOTODIODES Company Component Class Sensibility (d. Bm) Sensibility (m. W) Saturation (d. Bm) Saturation (m. W) KYOSEMI KPGX 1 G Ga. As PD-TIA -24 3. 98 E-03 - - KYOSEMI KPIX 150 M-H 33 Si PD-TIA -31 7. 94 E-04 - - KYOSEMI KPIXAIG-T-ST Si APD-TIA -33 5. 01 E-04 - - OPTEK OPF 562 A Si PD -41 7. 94 E-05 -7 0. 200 Si PD -21. 9 6. 46 E-03 3 1. 995 TIA Circ OK but F<2 Mhz LASER COMP PDSIU 500 ST 83 -W-0 Reception Expected d. Bm Comments Fine, Low Power High-Pass filter F> 1 Mhz

6. Emiters Receivers Analysis Kyosemi Laser Components

6. Accuracy Improvements � Disk D=14 cm 8796 slots of 50 um � How to reach specifications (Interpolation): ◦ Actual accuracy: 710 u. Rad. ◦ Specifications: 25 u. Rad. ◦ Needed Improvement of factor 30. ◦ 1. Offline Processing (Software requirements) ◦ 2. Online Processing (Possible by hardware)

6. Accuracy Improvements � Disk D=14 cm 8796 slots of 50 um � How to reach specifications (Interpolation): ◦ Actual accuracy: 710 u. Rad. ◦ Specifications: 25 u. Rad. ◦ Needed Improvement of factor 30. ◦ 1. Offline Processing (Software requirements) ◦ 2. Online Processing (Possible by hardware)

6. Accuracy Improvements � 2. Online Processing � 1. Interpolation with previous cycle reference � � � Source of errors: Bad measurement in previous cycle = interpolations errors in next. Allways there will be a delay of 0. 5 cycle. Possible improvement: Histeresys when crosing zero.

6. Accuracy Improvements � 2. Online Processing � 2. Interpolation of Sin-Cos Encoders: � � Two fibers if working with Focuser (displaced 90 deg) No errors or delay: Relationship between signals Variations in speed applied immediately. Interpolation Unit + Quadrature decoder