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Table 1.
Photon budget for the mean quiet-Sun intensity at disk center at the three wavelengths under study.
| Quantity | Unit | 6302 Å | 4080 Å | 3140 Å | Source |
|---|---|---|---|---|---|
| Solar spectral irradiance (Is) | mW m−2 nm−1 | 1657.8 | 1526.2 | 721.25 | ATLAS 3 |
| Limb darkening factor (L) | 0.8238 | 0.7239 | 0.6739 | Cox (1999), Table 14.17 | |
| Solar flux at DC (Φ1) | mW m−2 nm−1 | 2012.38 | 2108.30 | 1070.26 | Is/L |
| Area of solar disk (A⊙) | sr | 6.59330 × 10−5 | 6.59330 × 10−5 | 6.59330 × 10−5 | π × (944.93421 × π/3600/180)2 |
| Solar flux at DC (Φ2) | J s−1 cm−2 nm−1 sr−1 | 3.05216 | 3.19764 | 1.62326 | Φ1/A⊙ |
| Photon energy (Eph) | J photon−1 | 3.1521 × 10−19 | 4.8688 × 10−19 | 6.3264 × 10−19 | hc/λ |
| Diffraction limit | km | 117 | 76 | 58 | 1.22λ × 3600 × 180 × 736.4/D/π |
| Pixel size (P) | km pixel−1 | 62.5 | 62.5 | 62.5 | ≈ critical sampling at 6302 Å |
| Collecting area (Acol) | cm2 | 7431.25 | 7431.25 | 7431.25 | (π/4)×(1002−23.22) |
| Spectral resolving pow. (R) | 150 000 | 150 000 | 150 000 | λ/Δλ | |
| Transmission (Tr) | 0.2 | 0.2 | 0.2 | Current SUNRISE/SUSI design | |
| Quantum efficiency (QE) | 0.6 | 0.6 | 0.6 | Own estimate | |
| Total integration time (tint) | s | 4.8 | 4.8 | 4.8 | Normal mode of Hinode/SP and SUSI |
| Polar. eff. of Stokes I (ϵI) | 1 | 1 | 1 | Theoretical maximum | |
| Polar. eff. of Q,U,V (ϵQUV) | 0.57735 | 0.57735 | 0.57735 | Theoretical maximum ( ) |
|
| Energy per pixel and s (Epx) | J pixel−1 s−1 | 161.339 × 10−13 | 109.432 × 10−13 | 42.753 × 10−13 | Φ2Acolλ(P/736.4π/180/3600)2/R |
| Photon rate (Φ3) | photons s−1 | 51 183 920 | 22 476 031 | 6 757 967 | Epx/Eph |
| # of e− per integration (Ne−) | electrons | 29 481 941 | 12 946 195 | 3 892 589 | Φ3 × Tr × QE × tint |
| Noise amplification (a)a | 3 | 3 | 3 | Martínez Pillet et al. (2011) | |
| S/N of Stokes I | 1810 | 1200 | 658 |
 |
|
| Noise of Stokes I | 5.5 × 10−4 | 8.3 × 10−4 | 1.5 × 10−3 |
 |
|
| Noise of Stokes Q,U,V | 9.6 × 10−4 | 1.4 × 10−3 | 2.6 × 10−3 |
 |
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