锑化铟探测器与碲镉汞探测器对比（F4）
1. Overview
1) Purpose
① Comparison of performances between MCT and InSb
② Both are F/4 detectors
2) Test procedure
① For 2 days, 2 times per day
a. Receive raw outputs of detectors for various blackbody temperatures
② MTF measurement by Slanted Edge Function
a. Model: ASIO (Janos technology)
Focal length: 25mm
F number: 2.3
3) Results
① Basic performances
a. Operability, NETD, Non-uniformity: Similar
b. Linearity: InSb is slightly better than MCT
② RNU(Residual Non-Uniformity); Corrected image performances
a. Target blackbody: 30℃
RNUs are similar level.
Soft defect: MCT is larger (poorer) than InSb
③ MTF
a. Comparison of MTF at Nyquist frequency
InSb is better than MCT
4) Summary
| Performances | MCT | InSb |
| Operability, NETD, Non-uniformity | Similar | |
| Linearity | 99.9941% (4N) | 99.9997% (5N) |
| Soft defect (Accumulated soft defect pixels from corrected image analysis*) |
Bad (more than 2000 pixels, 0.61%) |
Very low (only 50 pixels, 0.015%) |
| MTF | Good | Very good |
| MRTD | 160mK | 160mK |
2. Basic performances
1) Performances
| Items | LEO-MW (IWR mode) | DI640 (IWR mode) | ||
| Tint[msec] | 8.0 (30% wellfill@20℃) |
13.5 (50% wellfill@20℃) |
6.5 (30% wellfill@20℃) |
11.0 (50% wellfill@20℃) |
| Operability[%] | 99.97 | 99.97 | 99.99 | 99.99 |
| Response[mV] | 366.82 | 635.03 | 363.60 | 617.63 |
| NETD[mK] | 23.00 | 16.29 | 22.40 | 16.39 |
| Non-uniformity[%] | 1.85 | 1.77 | 1.50 | 1.47 |
| Linearity[%] | 99.99413 | - | 99.99968 | - |
| Conditions | <Operable pixels> NETD < 50mK Responsivity < ±30% Cold shield height : 19.1mm(F#4) FPA temp : 79.24K |
<Operable pixels> NETD < 50mK Responsivity < ±30% Cold shield height : 19.45mm(F#4) FPA temp: 77.01K |
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2) Response image
(Raw output)
<LEO-MW response map>
(8.0ms, IWR, Gray level range±30%)
<DI640 response map>
(6.5ms, IWR, Gray level range±30%)
3. Linearity
1) MCT(LEO-MW) : 99.99413% 4N
Linearity map (The whiter, the better) & histogram(99.99~100%) (@5~55℃, Tint 8.0ms, IWR)
2) InSb(DI640) : 99.99968% more than 5N
Linearity map (The whiter, the better) & histogram(99.99~100%) (@5~50℃, Tint 6.5ms, IWR)
4. MTF by Slanted edge function
1) MTF values in the graphs (13.1% and 14.7%) include all of other
components including lens.
So, values themselves do NOT represent MTF values of detectors.
2) However, we can compare two values side by side, since all other
conditions are exactly same (optics(lens), computer, analysis S/W,
measurement room, etc)
MCT LEO-MW
InSb DI640
5. MRTD measurement
1) Test condition
① Collimator: manufactured by i3system
② 4 bar pattern of type-b 0.61 cycles/mrad
2) Test result
① Both detectors show same MRTD. No difference.
