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Figure 3
(a) Sample position and velocity versus time during a plunge into LN2, as recorded using the motor encoder of the sample vertical translation stage. The position of the LN2–gas interface and the hard stop of the vertical stage are indicated by horizontal dashed lines. In this case, the speed on entering the LN2 is 2.3 m s−1 and the brake was not applied. (b) Temperature versus time during a plunge as in (a) recorded using a thermocouple with a 23 µm bead and 12.5 µm leads and using a thermocouple with a 115 µm bead and 75 µm leads, with a speed on entering the LN2 of 2.3 m s−1. The corresponding cooling rates between 273 and 200 K are 46 ×103 and 5.3 × 103 K s−1, respectively, and those between 273 and 150 K are 40 × 103 and 5.0 × 103 K s−1, respectively. Assuming a power-law scaling of cooling rate with bead size, the corresponding cooling times for a 60 µm thick sample will be roughly 4.2 ms to 200 K and 8.0 ms to 150 K.

IUCrJ
Volume 12| Part 3| May 2025|
ISSN: 2052-2525
https://doi.org/10.1107/S205225252500288X