Secondary ion mass spectrometer

Abstract

A secondary ion mass spectrometer including primary ion emitting means for generating a primary ion to irradiate a specimen with the primary ion, means for separating secondary ions sputtered from the specimen, in accordance with mass-to-charge ratios, and detection means for detecting a secondary ion current emerging from the secondary ion separating means is disclosed, in which, when the value of the secondary ion current becomes greater than the upper limit of the dynamic range of the detecting means, the secondary ion current is attenuated by an attenuator, and the value of secondary ion current detected by the detection means is divided by the attenuation factor of the attenuator to obtain a corrected value. Thus, the secondary ion mass spectrometer is prevented from producing an erroneous analytical result due to the saturation of the detection means, that is, has a wide dynamic range, in which the amount of secondary ion varies by eight to ten orders of magnitude. Accordingly, the sescondary ion mass spectrometer can quantitatively determine a high-concentration element and a considerably-low-concentration element at the same time, and can determine the concentration distribution of an analytical element in a wide concentration range from a large value to a considerably small value.