title: Radiation damage in electron microscopy of organic materials: effect of low temperatures.
abstract: As measured by the life-time of their electron diffraction patterns, the radiation sensitivity of anthracene and coronene at 500 kV is reduced by a factor of three to four at liquid helium temperature in comparison to room temperature, For l-valine the ratio is about 1-8 but there is a wide variation in the results, possibly due to differences in crystal thickness. The end-dose at 20 degrees K for valine is equivalent to 13 electrons/A2; for anthracene and coronene it is about 600 electrons/A2 at room temperature. The variation of end-dose with temperature shows that at least two mechanisms must be involved in damage to such compounds, possibly concerning the breaking of intermolecular and intramolecular bonds, respectively.
mesh_terms: D000873:Anthracenes / Q000528:radiation effects*; D003080:Cold Temperature; D008854:Microscopy, Electron; D011083:Polycyclic Compounds / Q000528:radiation effects*; D011830:Radiation Effects; D014633:Valine / Q000528:radiation effects
chemical_list: D000873:Anthracenes; D011083:Polycyclic Compounds; D014633:Valine