Table 1. Physical parameters relevant to sample X-ray beam-induced heating and their abbreviations and values as used in this work.
Kinematic viscosities and thermal conductivities were taken from Kriminski et al. (2003 ▸).
| Abbreviation | Quantity | Units and typical value where applicable |
|---|---|---|
| c | Specific heat capacity | 5 × 102 J K−1 kg−1 (protein) |
| 7.5 × 102 J K−1 kg−1 (ruby) | ||
| ρ | Density of sample | 1.2 × 103 kg m−3 (protein) |
| 3.98 × 103 kg m−3 (ruby) | ||
| μabs | X-ray absorption coefficient | 8.93 mm−1 (ruby at 9.2 keV) |
| 3.27 mm−1 (ruby at 12.8 keV) | ||
| L xtal | Size of crystal | m |
| ν | Kinematic viscosity of gas stream | 1.9 × 10−6 J K−1 kg−1 m2 s−1 (nitrogen, 100 K) |
| 20 × 10−6 J K−1 kg−1 m2 s−1 (helium, 100 K) | ||
| κ | Thermal conductivity of cryogen | 9.8 × 10−3 W m−1 K−1 (nitrogen, 100 K) |
| 7.6 × 10−3 W m−1 K−1 (helium, 100 K) | ||
| u | Velocity of cryogen | ∼3.3 m s−1 (estimated from flow rate; Section 2.2) |