Intra-pixel Sensitivity Testing Preliminary Design Review 3 August 2001 Stella Jang SPACE TELESCOPE SCIENCE INSTITUTE

Goals Present the calibrated target/ 3-axis stage design Present requirements for blackbody radiation contrast and pixel saturation Show that the proposed design meets the necessary requirements Show that required tolerances can be met Approve a plan for moving from PDR to CDR 14 November 2018 2

Definition of Intra-pixel Sensitivity Ni,j =number of electrons/second detected in pixel i,j ei,j(x,y) =intra-pixel sensitivity at x,y in pixel i,j I =number of photons/second arriving at x,y in pixel i,j j+2 j+1 j i i+1 i+2 i+3 14 November 2018 3

Definition of Intra-pixel Sensitivity Figure 8. DRM-quality photometry (1%) cannot be achieved according to our measurements of intra-pixel sensitivity. (Left) Intra-pixel sensitivity of HgCdTe to a point source measured by Co-I Finger. (Right) NICMOS magnitude errors as a function of intra-pixel source location (Stiavelli, private communication). 14 November 2018 4

IPS Experiment Requirements (from TFST0900, Table 1) Wavelength range 0.5 – 5.5 mm Sampling 5x5 – 10x10 per pixel with 1%relative position error Image size < 5 mm FWHM over 10 x 10 pixel central region, no requirement outside this area 14 November 2018 5

NGST Requirements NDC0200 (from NGST Doc. #641) 14 November 2018 6

Modules pinhole Offner light source light guide focal reducer 3-axis stage filters window 14 November 2018 7

Layout with f/1.5 focal reducer 45° flat 45° flat Offner secondary f/10 point source detector focal reducer filter window Offner primary 14 November 2018 8

Shaded model -- with focal reducer 14 November 2018 9

Close-up of f/1.5 focal reducer 14 November 2018 10

Modules Requirements 14 November 2018 11

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PSF 14 November 2018 14

10 x 10 pixel field (l = 5 mm) 14 November 2018 15

Flux Equation T =temperature of source QE =absolute quantum efficiency of detector Toptics =transmission of window, mirrors, and central obscuration of the focal reducer Tvar =variable transmission at light guide exit port TPK50 =transmission of PK50 blocking filter Tfilter =transmission of bandpass filter W =solid angle subtended by entrance pupil at source A =area of emitting surface ti =integration time 14 November 2018 16

T=300K 14 November 2018 17

T=3250K 14 November 2018 18

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PK50 light guide 14 November 2018 20

Johnson-R 14 November 2018 21

Johnson-R 14 November 2018 22

Johnson-I 14 November 2018 23

Johnson-I 14 November 2018 24

J 14 November 2018 25

J 14 November 2018 26

H 14 November 2018 27

H 14 November 2018 28

K 14 November 2018 29

K 14 November 2018 30

L’ 14 November 2018 31

L’ 14 November 2018 32

M’ 14 November 2018 33

M’ 14 November 2018 34

Software Requirements Integrated control software exposure (multi-plane FITS) filter wheels 3D stage light source (on/off and intensity)? Analysis software data reduction pipeline IDL 14 November 2018 35

Designs Light source - Coherent quartz tungsten halogen -150W/3250K - Variable intensity Light guide - Coherent 24” multi-fiber gooseneck - 5.54mm exit port diameter Pinhole - 5 mm diameter in a 1” retaining ring mount 3-axis stage - 3 Newport compact motorized translation stages - Newport motion controller Window - 110mm - 10mm thickness - Mounted in end plate of dewar. Filters - Johnson-R, Johnson-I, J, H, K, L’, M’, PK50 14 November 2018 36

Designs (cont’d) Offner relay - Re-images source 1:1 onto detector Allows decent imaging at f/10 over full 2K2 field Provides excellent imaging over a smaller central region Compact, folded design fits available space All reflective optical design is free from chromatic aberration Focal reducer - Produces f/1.5 beam for sub-pixel imaging At f/10, diffraction-limited FWHM = 22.6 mm (l = 2.2 mm) At f/1.5, diffraction-limited FWHM is = 3.4 mm (l = 2.2 mm) Single-element optic with 4 different surface radii (2 elliptical, 2 spherical) Reflective coatings on the two elliptical surfaces Parfocal with f/10 beam, designed to reside in a filter wheel Provides subpixel imaging over a 10 pixel diameter region 14 November 2018 37

Designs 14 November 2018 38

Hardware Set-up 3-axis motion stages are assembled and attached to the motion driver Pinhole and light source needs to be attached to 3-axis stage Flux from light guide exit port must be variable 14 November 2018 39

Notes on Schedule Some hardware not ordered yet Anticipate that the hardware will be complete no earlier than December 14 November 2018 40

Open Issues Controlling efficiency at the light guide exit port This has implications for the pinhole/stage design M’ filter bandwidth How to suppress flux for wavelength < 4 mm ? Monochromator vs. Filters Cost Time 14 November 2018 41