Fast atom bombardment

[5][6][7] In FAB and LSIMS, the material to be analyzed is mixed with a non-volatile chemical protection environment, called a matrix, and is bombarded under vacuum with a high energy (4000 to 10,000 electron volts) atomic beam.

FAB was designed as an improved version of SIMS that allowed for the primary beam to no longer cause damaging effects to the sample.

The sample-matrix mixture is loaded on a stainless steel sample target on the probe, which is then placed in the ion source via a vacuum lock.

The alternative method of introducing the sample is by using a device called continuous flow fast atom bombardment (CF)-FAB.

In continuous flow fast atom bombardment (CF-FAB), the sample is introduced into the mass spectrometer insertion probe through a small diameter capillary.

[12] (CF)-FAB was developed to minimize the problem of poor detection sensitivity that is caused by an excess of the matrix background that results in a high matrix-to-sample ratio.

In 1983 a paper was published describing the use of fast atom bombardment mass spectrometry (FAB-MS) to analyze isotopes of calcium.

[20] Signal acquisition systems were sometimes modified to perform peak jumping instead of scanning and to do ion counting detection.

[21] While satisfactory precision and accuracy were attained with FAB-MS, the technique was labor-intensive with a very low sample through-put rate due in part to the absence of auto-sampling options.