Categories of exhibits
Cesium ion gun assembly
Exhibit no. 215
Liquid secondary ion mass spectrometry (LSIMS) is an ionization technique in mass spectrometry in which a beam of high-energy ions strikes a surface to create ions to be analyzed. It is closely related to fast atom bombardment (FAB), where a beam of high-energy atoms is used instead of ions. Ions in LSIMS are created by ion guns. The cesium ion gun produces positively charged cesium ions, which bombard the sample with high keV energies. The main advantage of the cesium ion gun when compared with the xenon atom gun used in FAB is higher sensitivity at high mass.
The cesium ion gun consists of a cesium ion emitter (or anode) which emits cesium ions from a cesium salt when it is heated. Lens elements focus and accelerate the ions emitted from the anode towards the sample.
Pictured is the cesium ion gun assembly from sector mass spectrometer ZAB EQ manufactured by VG Analytical Ltd. in 1986. The anode potential was up to 35 kV and warm up time from cold was 10 - 15 minutes.
