Electron impact time of flight spectrometer

Claim 2

An electron monochromator suitable for use in an electron spectrometer comprising: a source of electrons having an initial relative energy spread, drift tube means for providing a field free drift space through which said electrons may be passed, electronic gating means disposed between said source and one end of said drift tube means for periodically selecting discrete bunches of said electrons and causing them to pass through said drift tube means, and means creating a dynamic electric field at the other end of said drift tube means for differentially accelerating said electrons passing out of said drift tube means to produce bunches of monoenergic electrons.

Claim 3

An electron monochromator as defined in claim 1 wherein said differential accelerating means comprises electrode means disposed proximate said other end of said drift tube means and a voltage supply means synchronized with said gating means for providing a predetermined time varying voltage to said electrodes for creating said dynamic electric field and causing the energy potential of all of said electrons to be the same.

Claim 4

An electron analyzer comprising; a source of electrons having an initial relative energy spread, first means providing a first field free drift space through which said electrons may be caused to pass, gating means disposed between said source of electrons and one extremity of said drift space for selecting discrete bunches of said electrons emitted from said source and causing them to pass through said drift space, second means providing a second field free drift space through which said electrons may be passed, means creating a dynamic electric field between said first and said second means for differentially accelerating said electrons passing out of said first drift space to produce bunches of monoenergic electrons which are caused to converge and form discrete bunches having different energy levels spaced in time relative to each other upon reaching another extremity of said second drift space, a sample chamber between said first and said second means through which said electrons may be passed so as to enable an energy transformation to occur between said electrons and a sample disposed in said chamber, and means for detecting said bunches of electrons as they emerge from said drift space.

Claim 5

An electron analyzer comprising; a source of electrons having an initial relative energy spread, first means providing a first field free drift space through which said electrons may be caused to pass, gating means disposed between said source of electrons and one extremity of said drift space for selecting discrete bunches of said electrons emitted from said source and causing them to pass through said drift space, second means providing a second field free drift space through which said electrons may be passed, means creating a dynamic electric field between said first and said second means for differentially accelerating said electrons passing out of said first drift space to produce bunches of monoenergic electrons which are caused to converge and form discrete bunches having different energy levels spaced in time relative to each other upon reaching another extremity of said second drift space, a sample chamber between said first and said second means through which said electrons may be passed so as to enable an energy transformation to occur between said electrons and a sample disposed in said chamber, and means for detecting said bunches of electrons as they emerge from said drift space.

Claim 6

An electron analyzer as recited in claim 3 wherein said detecting means includes an electron gating means which allows electrons to pass therethrough to a collector means only during short intervals of time, and variable electron accelerating means for enabling the selective determination, according to energy level, of which bunch of electrons is to be allowed to pass through said gate during said short intervals of time.

Claim 7

An electron analyzer as described in claim 3 wherein said electron accelerating means comprises an electrode means for creating a time varying electric field between the adjacent extremities of said first and second drift space means in response to a time varying voltage applied thereto and voltage source means synchronized with said gating means for applying a predetermined time varying voltage to said electrode.

Claim 8

An electron analyzer as described in claim 5 wherein said voltage source means includes a sinusoidal oscillator means having a sinusoidal output of such frequency, phase and amplitude that when applied to said electrode means it causes said time varying electric field to change linearly during the time of transit of said electrons through said field.

Claim 9

An electron impact spectrometer apparatus comprising: a source of electrons having an initial relatiVe energy spread, first drift tube means providing a first field free drift space through which said electrons may be caused to pass, gating means disposed between said electron source and one end of said drift tube means for causing discrete bunches of said electrons to be propelled through said drift tube means, a sample chamber through which said electrons may be passed so as to enable an energy transformation to occur between said electrons and a sample disposed in said chamber, means creating a dynamic electric field at the other end of said drift tube means for differentially accelerating said electrons passing out of said drift tube means to produce bunches of monoenergic electrons, second drift tube means for providing a second field free drift space through which said electrons are passed after passing through said sample chamber, and means for detecting said electrons as they emerge from said last mentioned drift tube means so as to provide an indication of the energy loss sustained by said electrons during their transit through said sample.

Claim 10

An electron impact spectrometer apparatus comprising: a source of electrons having an initial relatiVe energy spread, first drift tube means providing a first field free drift space through which said electrons may be caused to pass, gating means disposed between said electron source and one end of said drift tube means for causing discrete bunches of said electrons to be propelled through said drift tube means, a sample chamber through which said electrons may be passed so as to enable an energy transformation to occur between said electrons and a sample disposed in said chamber, means creating a dynamic electric field at the other end of said drift tube means for differentially accelerating said electrons passing out of said drift tube means to produce bunches of monoenergic electrons, second drift tube means for providing a second field free drift space through which said electrons are passed after passing through said sample chamber, and means for detecting said electrons as they emerge from said last mentioned drift tube means so as to provide an indication of the energy loss sustained by said electrons during their transit through said sample.

Claim 11

An electron impact spectrometer as recited in claim 7 wherein said detecting means includes a collector means disposed proximate the downstream end of said second drift tube means, electron gating means disposed between said collector means and said downstream end of said second drift tube means for allowing electrons to pass therethrough to said collector means only during short intervals of time, and means for creating a variable accelerating electric field between said downstream end of said second drift tube means and said electron gating means so that electrons of selected energy levels may be preferentially caused to pass through said gating means during said short periods of time.

Claim 12

An electron impact spectrometer as recited in claim 7 wherein said electron accelerating means comprises means for creating a time varying electric field between said other end of said first drift space means and said sample chamber means in response to a time varying voltage applied thereto and voltage source means synchronized with said gating means for applying a predetermined time varying voltage to said electrode.

Claim 13

An electron impact spectrometer as recited in claim 9 wherein said voltage source means includes a sinusoidal oscillating means having a sinusoidal output of such frequency, phase and amplitude that when applied to said electron accelerating means it causes said time varying electric field to change linearly during the time of transit of said electrons through said field.