Environmental Scanning Electron Microscope - Commercial ESEM

Commercial ESEM

The ESEM has appeared under different manufacturing brand names. The term ESEM is a generic name first publicly introduced in 1980 and afterwards unceasingly used in all publications by Danilatos and almost all users of all ESEM type instruments. The ELECTROSCAN ESEM trademark was obtained intermittently until 1999, when it was allowed to lapse. The word “environmental” was originally introduced in continuation to the prior (historical) use of “environmental” cells in transmission microscopy, although the word “atmospheric” has also been used to refer to an ESEM at one atmosphere pressure (ASEM) but not with any commercial instruments. Other competing manufacturers have used the terms “Natural SEM” (Hitachi), “Wet-SEM” (ISI), “Bio-SEM” (short-lived, AMRAY), “VP-SEM” (variable-pressure SEM; LEO/Zeiss-SMT), “LVSEM” (low-vacuum SEM, often also denoting low-voltage SEM; JEOL), all of which seem to be transient in time according to prevailing manufacturing schedules. Until recently, all these names referred to instruments operating up to about 100 Pa and with BSE detectors only. Lately, the Zeiss-SMT VP-SEM has been extended to higher pressure together with a gaseous ionization or gaseous scintillation as the SE mechanism for image formation. Therefore, it is improper to identify the term ESEM with one only brand of commercial instrument in juxtaposition to other competing commercial (or laboratory) brands with different names, as some confusion may arise from past use of trademarks.

Similarly, the term GDD is generic covering the entire novel gaseous detection principle in ESEM. The terms ESD and GSED, in particular, have been used in conjunction with a commercial ESEM to denote the secondary electron mode of this detector.