A cryo-electron microscope operates at

PHYSICS · Subjective · Fermi University Physics · Optics & Photonics · Biophysics & Medical Physics · Macromolecules, membranes and cell architecture

Forces, Machines and Signals, Ch Seeing molecules: diffraction, cryo-electron microscopy and fluorescence

Problem

300\,\mathrm{kV}

, giving electrons of wavelength

\lambda = 1.97\,\mathrm{pm}

. A micrograph is recorded with defocus

\Delta f = 0.50\,\mathrm{\mu m}

. Using the first-zero condition

q = 1/\sqrt{\lambda\Delta f}

for the contrast transfer function (ignoring spherical aberration), find the real-space spacing

d = 1/q

corresponding to the first CTF zero.