Mechanical Tolerancing Results For the SALT/PFIS Collimator and Camera. January 24, 2003 J. Alan Schier

Transcription

1 Mechanical Tolerancing Results For the SALT/PFIS Collimator and Camera January 24, 2003 J. Alan Schier This report contains the tolerance information needed to produce a mechanical design for the SALT/PFIS optical assemblies. We produced this information using Zemax, starting with an optical prescription and merit function provided by the PFIS project. The system was then subject to Monte Carlo simulations to find an acceptable set of tolerances. In the course of the work, we found that the merit function used in the Monte Carlo simulation did not fully reflect the necessary performance of the system. To overcome this, Dr. Kenneth Nordsieck examined the results and evaluated them against the necessary performance criteria. In this way we were able to arrive at a final set of mechanical tolerances suitable for the design of the optical assemblies. The final tolerances are listed in Appendix A. They represent the portion of the error budget allocated to the mechanical fabrication and assembly of the collimator and camera. During the Monte Carlo simulations, we allowed the system to refocus for each of the three spectroscopic configurations. Additionally, we allowed the last element and detector to tilt as a group about the local X axis (in Zemax coordinates) in order to compensate for other tolerances. The particular tolerances used in the simulation represent an assembly technique where the multiplets are first assembled as accurate subassemblies, and these subassemblies then placed into the final configuration. For that reason, one will note tilt and positioning tolerances for entire groups of elements. The resulting tolerances embody several notable points. In general, the allowable tolerance for the tilt of an element is ±0.032, and for the positioning, ±0.075 mm. These tolerances are within the capabilities of careful conventional machining and assembly techniques. In two exceptional cases, the tolerances are more difficult to achieve. In the first case, lens 3 must be constrained to a tilt and decenter of less than ±0.016 and ±0.050 mm (see the system prescription in Appendix C for element designations). In the second case, group 4 (lenses 5 through 7, or surfaces 21 through 24 in the optical prescription) must be centered to within ±0.050 mm. These tolerances are on the "ragged edge" of what is reasonable with conventional fabrication techniques. Notwithstanding, they are feasible because of the tilt and centering adjustments that will be available at assembly. Furthermore, the difficulties are somewhat mitigated by the fact that these tightest tolerances are located in a compact area near the front of the collimator. This allows one to assemble and align the elements as a subassembly. The situation would have been more difficult were there a large physical distance between the elements or had they been located within the focus mechanism in the camera. Our initial tolerancing work indicated the need for tighter tolerances than those reported here. In examining the first results, Dr. Nordsieck was able to identify tilt of the dewar containing the last element and detector as a strong compensating factor. As such, tilting the dewar about the X axis (in Zemax coordinates) cancels much of the error introduced by other tilt and positioning tolerances. Were this not the case, fabrication and assembly would have been considerably more involved, with a corresponding costs increased of perhaps 50%.

2 Appendix A: Tolerance Listing Tolerance Data Listing File : C:\Documents and Settings\Rosey\Personal\1 Projects\Active\PFIS\Tolerancing report\final data, 4 comp restart 2\Manual Tol Base.zmx Title: SALT PFIS Date : FRI JAN Num Type Int1 Int2 Int3 Nominal Min Max Units Comments 1 (CPAR) E E+000 G9 X tilt 2 (TSTX) E E-002 Degrees L2 X tilt 3 (TSTY) E E-002 Degrees L2 Y tilt 4 (TTHI) E E E-002 Millimeters G1-G2 spacing 5 (TEDX) E E-002 Millimeters G2 X decenter 6 (TEDY) E E-002 Millimeters G2 Y decenter 7 (TETX) E E-002 Degrees G2 X tilt 8 (TETY) E E-002 Degrees G2 Y tilt 9 (TTHI) E E E-002 Millimeters G2-G3 spacing 10 (TEDX) E E-002 Millimeters G3 X decenter 11 (TEDY) E E-002 Millimeters G3 Y decenter 12 (TETX) E E-002 Degrees G3 X tilt 13 (TETY) E E-002 Degrees G3 Y tilt 14 (CMCO) E E+001 Compensator, config. 1 focus 15 (CMCO) E E+001 Compensator, config. 2 focus 16 (CMCO) E E+001 Compensator, config. 3 focus 17 (TTHI) E E E-002 Millimeters G3-G4 spacing 18 (TEDX) E E-002 Millimeters G4 X decenter 19 (TEDY) E E-002 Millimeters G4 Y decenter 20 (TETX) E E-002 Degrees G4 X tilt 21 (TETY) E E-002 Degrees G4 Y tilt 22 (TSTX) E E-002 Degrees L6 X tilt 23 (TSTY) E E-002 Degrees L6 Y tilt 24 (TSTX) E E-002 Degrees L7 X tilt 25 (TSTY) E E-002 Degrees L7 Y tilt 26 (TTHI) E E E-001 Millimeters G4-G5 spacing 27 (TEDX) E E-002 Millimeters G5 X decenter 28 (TEDY) E E-002 Millimeters G5 Y decenter 29 (TETX) E E-002 Degrees G5 X tilt 30 (TETY) E E-002 Degrees G5 Y tilt 31 (TSTX) E E-002 Degrees L9 X tilt 32 (TSTY) E E-002 Degrees L9 Y tilt

3 33 (TTHI) E E E+000 Millimeters Collimator to grating spacing 34 (TTHI) E E E+000 Millimeters Grating to camera spacing 35 (TEDX) E E-002 Millimeters G6 X decenter 36 (TEDY) E E-002 Millimeters G6 Y decenter 37 (TETX) E E-002 Degrees G6 X tilt 38 (TETY) E E-002 Degrees G6 Y tilt 39 (TSTX) E E-002 Degrees L11 X tilt 40 (TSTY) E E-002 Degrees L11 Y tilt 41 (TSTX) E E-002 Degrees L12 X tilt 42 (TSTY) E E-002 Degrees L12 Y tilt 43 (TSTX) E E-002 Degrees L13 X tilt 44 (TSTY) E E-002 Degrees L13 Y tilt 45 (TEDX) E E-002 Millimeters G7 X decenter 46 (TEDY) E E-002 Millimeters G7 Y decenter 47 (TETX) E E-002 Degrees G7 X tilt 48 (TETY) E E-002 Degrees G7 Y tilt 49 (TTHI) E E E-002 Millimeters G7-G8 50 (TEDX) E E-002 Millimeters G8 X decenter 51 (TEDY) E E-002 Millimeters G8 Y decenter 52 (TETX) E E-002 Degrees G8 X tilt 53 (TETY) E E-002 Degrees G8 Y tilt 54 (TSTX) E E-002 Degrees L16 X tilt 55 (TSTY) E E-002 Degrees L16 Y tilt 56 (TSTX) E E-002 Degrees L17 X tilt 57 (TSTY) E E-002 Degrees L17 Y tilt 58 (TEDX) E E-002 Millimeters G9 X decenter 59 (TEDY) E E-002 Millimeters G9 Y decenter 60 (TETY) E E-002 Degrees G9 Y tilt 61 (TTHI) E E E-001 Millimeters G9-detector (BFD) 62 (TSTX) E E-002 Degrees Focal surface X tilt 63 (TSTY) E E-002 Degrees Focal surface Y tilt

4 Appendix B: Tolerance Sensitivities and Monte Carlo Results Analysis of Tolerances File : C:\Documents and Settings\Alan\My Documents\Work\PFIS Zemax work\tolerancing report\manual Tol Base.zmx Title: SALT PFIS Date : FRI JAN Analysis for all 3 configurations. Units are Millimeters. WARNING: Solves should be removed prior to tolerancing. Compensator: Parameter 3 on surface 59, Min = , Max = Compensator: Multi-Configuration Operand 17 on Configuration 1, Min = , Max = Compensator: Multi-Configuration Operand 17 on Configuration 2, Min = , Max = Compensator: Multi-Configuration Operand 17 on Configuration 3, Min = , Max = WARNING: RAY AIMING IS OFF. Very loose tolerances may not be computed accurately. WARNING: Boundary constraints on compensators are ignored when using fast mode or user-defined merit functions. Criteria : User defined merit function Mode : Sensitivities Optimization Cycles : Automatic mode Nominal Criteria : Test Wavelength : Fields: User Defined Angle in degrees # X-Field Y-Field Weight VDX VDY VCX VCY E E E E E E E E E E E E Sensitivity Analysis: Minimum Maximum Type Value Criteria Change Value Criteria Change TTHI TTHI TTHI TTHI TTHI TTHI TTHI TTHI TSTX TSTX TSTX TSTX TSTX TSTX TSTX TSTX TSTX TSTX TSTY TSTY TSTY TSTY TSTY TSTY TSTY TSTY TSTY TSTY TEDX TEDX TEDX

5 TEDX TEDX TEDX TEDX TEDX TEDY TEDY TEDY TEDY TEDY TEDY TEDY TEDY TETX TETX TETX TETX TETX TETX TETX TETY TETY TETY TETY TETY TETY TETY TETY Worst offenders: Type Value Criteria Change TEDY TEDX TETX TEDX TEDX TEDY TEDY TETX TEDX TETY TEDY TETY TETX TTHI TETX TEDX TEDX TETX TTHI TETY Nominal Merit Function : Estimated change : Estimated Merit Function : Merit Statistics: Mean : Standard Deviation : Compensator Statistics: Parameter 3 Surf 59: Minimum : Maximum : Mean : Standard Deviation : Multiconfig Operator 17 Config 1: Minimum : Maximum : Mean : Standard Deviation :

6 Multiconfig Operator 17 Config 2: Minimum : Maximum : Mean : Standard Deviation : Multiconfig Operator 17 Config 3: Minimum : Maximum : Mean : Standard Deviation : Monte Carlo Analysis: Number of trials: 30 Initial Statistics: Uniform Distribution Trial Criteria Change Nominal Best Worst Mean Std Dev Compensator Statistics: Parameter 3 Surf 59: Minimum : Maximum : Mean : Standard Deviation : Multiconfig Operator 17 Config 1: Minimum : Maximum : Mean : Standard Deviation : Multiconfig Operator 17 Config 2:

7 Minimum : Maximum : Mean : Standard Deviation : Multiconfig Operator 17 Config 3: Minimum : Maximum : Mean : Standard Deviation : % of Monte Carlo lenses have a merit function below % of Monte Carlo lenses have a merit function below % of Monte Carlo lenses have a merit function below End of Run.

8 Appendix C: System Prescription, Including Multi-Configuration Information System/Prescription Data File : C:\Documents and Settings\Rosey\Personal\1 Projects\Active\PFIS\Tolerancing report\final data, 4 comp restart 2\Manual Tol Base.zmx Title: SALT PFIS Date : FRI JAN Configuration 1 of 3 LENS NOTES: Notes... PFIS Pre-fabrication Design GENERAL LENS DATA: Surfaces : 62 Stop : 1 System Aperture : Entrance Pupil Diameter = Glass Catalogs : pfis_0206 schott Ray Aiming : Off Apodization : Uniform, factor = E+000 Temperature (C) : E+001 Pressure (ATM) : E+000 Effective Focal Length : (in air at system temperature and pressure) Effective Focal Length : (in image space) Back Focal Length : Total Track : Image Space F/# : Paraxial Working F/# : Working F/# : Image Space NA : Object Space NA : 5.5e-007 Stop Radius : 5500 Paraxial Image Height : Paraxial Magnification : 0 Entrance Pupil Diameter : Entrance Pupil Position : 0 Exit Pupil Diameter : Exit Pupil Position : Field Type : Angle in degrees Maximum Field : Primary Wave : 0.5 Lens Units : Millimeters Angular Magnification : Fields : 4 Field Type: Angle in degrees # X-Value Y-Value Weight Vignetting Factors # VDX VDY VCX VCY VAN Wavelengths : 4 Units: Microns # Value Weight

9 SURFACE DATA SUMMARY: Surf Type Comment Radius Thickness Glass Diameter Conic OBJ STANDARD Infinity Infinity 0 0 STO PARAXIAL SALT PRIMARY PARAXIAL SAC STANDARD PUPIL Infinity STANDARD FOCUS Infinity STANDARD L F_QUARTZ STANDARD L CAF STANDARD STANDARD HALFWAVEPLATE Infinity F_QUARTZ STANDARD Infinity STANDARD QUARTERWAVEPLATE Infinity F_QUARTZ STANDARD COMPENSATOR Infinity STANDARD Infinity STANDARD L F_QUARTZ STANDARD STANDARD COMPENSATOR Infinity STANDARD Infinity STANDARD L F_QUARTZ STANDARD STANDARD COMPENSATOR Infinity STANDARD Infinity STANDARD L CAF STANDARD L NACL STANDARD L CAF STANDARD STANDARD COMPENSATOR Infinity STANDARD Infinity STANDARD L8 Infinity 15 F_SILICA STANDARD L CAF STANDARD STANDARD SHUTTER Infinity COORDBRK STANDARD GR SUBSTRATE Infinity 10 F_SILICA DGRATING PUPIL/ GRATING Infinity 10 F_SILICA STANDARD Infinity COORDBRK EVENASPH L F_SILICA STANDARD L CAF STANDARD L F_SILICA STANDARD L CAF STANDARD STANDARD COMPENSATOR Infinity STANDARD FOCUS Infinity STANDARD FOCUS SHIFT Infinity STANDARD L CAF STANDARD BAFFLE Infinity 27 CAF STANDARD STANDARD COMPENSATOR Infinity STANDARD Infinity STANDARD L F_SILICA STANDARD L NACL STANDARD L F_SILICA STANDARD STANDARD -FOCUS SHIFT Infinity STANDARD FOCUS END Infinity STANDARD COMPENSATOR Infinity STANDARD FILTER Infinity 8 F_SILICA STANDARD COMPENSATOR Infinity STANDARD Infinity COORDBRK COMP.: X TILT STANDARD L F_SILICA STANDARD IMA STANDARD Infinity 116 0

10 MULTI-CONFIGURATION DATA: Configuration 1: 1 Config Weight : 1 2 Temperature : 20 3 Pressure : 1 4 Param 3 31 : Param 1 33 : Param 2 33 : -1 7 Wavelength 1 : Wavelength 2 : Wavelength 3 : Wavelength 4 : Wave wgt 1 : Wave wgt 2 : Wave wgt 3 : 1 14 Wave wgt 4 : 1 15 Thickness 42 : 2 16 Thickness 54 : 2 Pick up from configuration 1, operand 15, scale -1, offset 4 17 Thickness 43 : 0 Configuration 2: 1 Config Weight : 1 2 Temperature : 20 3 Pressure : 1 4 Param 3 31 : Param 1 33 : Param 2 33 : -1 7 Wavelength 1 : Wavelength 2 : Wavelength 3 : Wavelength 4 : Wave wgt 1 : 2 12 Wave wgt 2 : 3 13 Wave wgt 3 : 1 14 Wave wgt 4 : 1 15 Thickness 42 : Thickness 54 : Pick up from configuration 2, operand 15, scale -1, offset 4 17 Thickness 43 : 0 Configuration 3: 1 Config Weight : 1 2 Temperature : 20 3 Pressure : 1 4 Param 3 31 : Param 1 33 : Param 2 33 : -1 7 Wavelength 1 : Wavelength 2 : Wavelength 3 : Wavelength 4 : Wave wgt 1 : 2 12 Wave wgt 2 : 3 13 Wave wgt 3 : 1 14 Wave wgt 4 : 1 15 Thickness 42 : Thickness 54 : Pick up from configuration 3, operand 15, scale -1, offset 4 17 Thickness 43 : 0 SOLVE AND VARIABLE DATA: Semi Diameter 5 : Fixed Semi Diameter 6 : Fixed Semi Diameter 7 : Fixed Semi Diameter 8 : Fixed Semi Diameter 9 : Fixed Semi Diameter 10 : Fixed Semi Diameter 11 : Fixed Semi Diameter 12 : Maximum Semi Diameter 13 : Fixed Semi Diameter 14 : Fixed

11 Semi Diameter 17 : Fixed Semi Diameter 18 : Fixed Semi Diameter 21 : Fixed Semi Diameter 22 : Fixed Semi Diameter 23 : Fixed Semi Diameter 24 : Fixed Semi Diameter 27 : Fixed Semi Diameter 28 : Fixed Semi Diameter 29 : Fixed Semi Diameter 32 : Maximum Semi Diameter 33 : Maximum Semi Diameter 34 : Maximum Parameter 3 Surf 35 : Pickup from 31 times , plus Semi Diameter 36 : Fixed Semi Diameter 37 : Fixed Semi Diameter 38 : Fixed Semi Diameter 39 : Fixed Semi Diameter 40 : Fixed Semi Diameter 44 : Fixed Semi Diameter 45 : Maximum Semi Diameter 46 : Fixed Semi Diameter 49 : Fixed Semi Diameter 50 : Fixed Semi Diameter 51 : Fixed Semi Diameter 52 : Fixed Thickness of 53 : Solve, pick up value from 43, scaled by , plus Semi Diameter 54 : Maximum Semi Diameter 56 : Maximum Semi Diameter 58 : Maximum Semi Diameter 60 : Fixed Semi Diameter 61 : Pickup from 60 Semi Diameter 62 : Fixed Config 1, Oper 16 Thickness 54 : 2 Pick up from configuration 1, operand 15, scale -1, offset 4 Config 2, Oper 16 Thickness 54 : Pick up from configuration 2, operand 15, scale -1, offset 4 Config 3, Oper 16 Thickness 54 : Pick up from configuration 3, operand 15, scale -1, offset 4

12 Appendix D: Merit Function The merit function used in the Monte Carlo simulations is the default merit generated by Zemax with the following parameters: Optimization function: RMS spot x+y relative to the centroid. Relative weighting of the X component:0.33. Integration method: Gauss Quadrature with 3 rings and 6 arms. The system was optimized with the fields, configurations, and wavelengths listed in Appendix C.

13 Appendix E: Optical Layout