A time of flight mass spectrometer , comprising: an input orifice for receiving ions, a first ion acceleration stage (Z1) for accelerating the ions along a first path , said first acceleration stage (Z1) comprising first and second electrodes separated by a selected distance (d1), wherein application of a voltage differential between said first and second electrodes generates an electrical field (E1) for accelerating the ions, a first ion reflector for receiving said accelerated ions and redirecting said ions along a second path different than the first path , a second ion reflector configured to redirect the ions propagating along the second path onto a third path , a detector for detecting at least a portion of the ions redirected by said second ion reflector , at least first and second field free drift regions (Z2, Z6) disposed between said first acceleration (Z1) stage and said detector , wherein said second field free region (Z6) is disposed in proximity of the detector , and a second acceleration stage (Z3) disposed between said first and second field free drift regions (Z2, Z6), a third electrode disposed at a distance relative to said second electrode , said second and third electrodes being held at a common voltage to generate said first field free drift region (Z2) there between, a first grid disposed between said third electrode and said first ion reflector , said third electrode and said grid being held at a voltage differential to provide said second acceleration stage (Z3) for ions traveling along said first path , wherein said first grid and said first ion reflector are held at a voltage differential configured to decelerate the ions as they propagate from said first grid to said first ion reflector , and wherein the lengths of the two field free drift regions are selected to provide at least first and second order correction of ion flight time to provide position focusing of the ions. an input orifice for receiving ions, a first ion acceleration stage (Z1) for accelerating the ions along a first path , said first acceleration stage (Z1) comprising first and second electrodes separated by a selected distance (d1), wherein application of a voltage differential between said first and second electrodes generates an electrical field (E1) for accelerating the ions, a first ion reflector for receiving said accelerated ions and redirecting said ions along a second path different than the first path , a second ion reflector configured to redirect the ions propagating along the second path onto a third path , a detector for detecting at least a portion of the ions redirected by said second ion reflector , at least first and second field free drift regions (Z2, Z6) disposed between said first acceleration (Z1) stage and said detector , wherein said second field free region (Z6) is disposed in proximity of the detector , and a second acceleration stage (Z3) disposed between said first and second field free drift regions (Z2, Z6), a third electrode disposed at a distance relative to said second electrode , said second and third electrodes being held at a common voltage to generate said first field free drift region (Z2) there between, a first grid disposed between said third electrode and said first ion reflector , said third electrode and said grid being held at a voltage differential to provide said second acceleration stage (Z3) for ions traveling along said first path , wherein said first grid and said first ion reflector are held at a voltage differential configured to decelerate the ions as they propagate from said first grid to said first ion reflector , and wherein the lengths of the two field free drift regions are selected to provide at least first and second order correction of ion flight time to provide position focusing of the ions. <EOS>