Micromass GCT

The Micromass GCT
is a compact, fully integrated, high performance, orthogonal acceleration time of flight mass spectrometer designed for GC-MS and probe MS
applications.

The system consists of a source and analyser housing separated by a pneumatic isolation valve and a differential pumping aperture. The source housing is fitted with a250 L/sec high compression turbomolecular pump. The analyser housing is fitted with a 70L/sec high compression turbomolecular pump. A single RV3 rotary pump backs both turbomolecular pumps.

GCT
Includes Electron Impact (EI), Chemical Ionisation (CI) and Field Ionisation (FI) source options. The ion source is at ground potential to allow simple direct coupling to the GC inlet, thereby minimising the possibility of cold spots. A source probe allows easy exchange of the EI and CI removable inner volumes, or of the FIemitter.

Ions are accelerated from the grounded ion source to 40eV before being accelerated orthogonally into the time of flight (TOF) mass analyser.

The TOF analyser has a two stage orthogonal acceleration region, followed by a single stage reflectron, giving an effective path length of 1.2 meter. Ions are detected using a dual microchannel plate assembly capable of detecting positive or negative ions. Ion arrival times are recorded
using a time to digital converter (TDC) with a sampling rate of 1 or 3.6GHz