Patent ID: 9728391
Date: 2017-08-08
CPC Classifications: G01N,H01J

Claim:
1. A Time of Flight mass analyser comprising: an annular ion guide having a longitudinal axis and comprising a first annular ion guide section and a second annular ion guide section; a first device arranged and adapted to introduce ions into said first annular ion guide section, wherein an electric field is applied to the first annular guide section so that said ions form substantially stable circular orbits within said first annular ion guide section about said longitudinal axis; an ion detector disposed within said annular ion guide; a second device arranged and adapted to orthogonally accelerate ions in a first axial direction from said substantially stable circular orbits within said first annular ion guide section into said second annular ion guide section such that ions follow substantially spiral paths as they pass through said second annular ion guide section; and a third device arranged and adapted to maintain an axial DC potential along at least a portion of said second annular ion guide section so that, in use, said ions are reflected in a second axial direction which is substantially opposed to said first axial direction and so that said ions undergo multiple axial passes through said second annular ion guide section before being detected by said ion detector whereby the time of flight of the ions is measured.