Electrostatic prism

Claim 2

An electrostatic prism device for creating a field to deflect particles of a beam of charged particles comprising: a source for producing a beam of charged particles; chamber means having an entrance aperture for passing said beam of charged particles into said chamber means; a pair of oppositely poled high transparency screen electrode means mounted within said chamber means in curved spaced apart relationship to create a curved electrostatic field space therebetween extending in an arc from said aperture so as to receive therein in said field space said beam of charged particles passing through said aperture into said chamber; and a pair of particle attractor means each exhibiting a voltage potential having a polarity opposite to that of the polarity of said charged particle, one of said pair of particle attractor means mounted within said chamber means, exterior to said field space, adjacent one of said high transparency screen electrode means and the other of said pair of particle attractor means mounted within said chamber means, exterior to said field space, adjacent the other of said high transparency screen electrode means.

Claim 3

The device as set forth in claim 1 wherein said chamber means includes exit aperture means at the end of said curved field space opposite said entrance aperture so that particles of selected energy traverse an angular path within said curved field space to said exit aperture.

Claim 4

The device as set forth in claim 2 wherein particle collection means act to collect and detect particles of said selected energy exiting through said exit aperture means.

Claim 5

The device as set forth in claim 1 further including a pair of particle collector means, one of said pair of particle collector means arranged to collect particles attracted by the said one of said particle attractor means and the other of said particle collector means arranged to collect particles attracted by the said other of said particle attractor means.

Claim 6

The device as set forth in claim 4 further including energy level discrimination plate means positioned at the end of said curved field space opposite to said entrance aperture so as to intercept selected particles within a predetermined narrow energy band to thereby divide the remainder of said particles into high and low energy groups.

Claim 7

An electrostatic prism device for creating a field to deflect particles of a beam of charged particles comprising: a source for producing a beam of charged particles; chamber means having an entrance aperture for passing said beam of charged particles into said chamber means; a pair of particle transmissive electrically conductive screening means mounted within said chamber means in curved spaced apart relationship extending in an arc from said aperture so as to receive in the space therebetween said beam of charged particles passing through said aperture into said chamber; means to apply a potential between said screening means to create an electrostatic field in said curved space therebetween for deflecting said beam of charged particles; and a pair of particle attractor means each biased with a voltage potential having a polarity opposite to that of the polarity of said charged particles one of said pair of particle attractor means mounted within said chamber means, exterior to said space, adjacent one of said screening means and the other of said pair of particle attraCtor means mounted within said chamber means, exterior to said space, adjacent the other of said screening means.

Claim 8

An electrostatic prism device for creating a field to deflect particles of a beam of charged particles comprising: a source for producing a beam of charged particles; chamber means having an entrance aperture for passing said beam of charged particles into said chamber means; a pair of particle transmissive electrically conductive screening means mounted within said chamber means in curved spaced apart relationship extending in an arc from said aperture so as to receive in the space therebetween said beam of charged particles passing through said aperture into said chamber; means to apply a potential between said screening means to create an electrostatic field in said curved space therebetween for deflecting said beam of charged particles; and a pair of particle attractor means each biased with a voltage potential having a polarity opposite to that of the polarity of said charged particles one of said pair of particle attractor means mounted within said chamber means, exterior to said space, adjacent one of said screening means and the other of said pair of particle attraCtor means mounted within said chamber means, exterior to said space, adjacent the other of said screening means.

Claim 9

The device asset forth in claim 6 wherein each of said pair of particle attractor means is in the form of a section of particle transmissive electrically conductive screening means and wherein said device further includes a pair of particle collection means with one of said pair of particle collection means mounted to collect particles passing through one of said pair of screening means and with the other of said pair of particle collection means mounted to collect particles passing through the other of said pair of screening means.

Claim 10

The device as set forth in claim 6 further including a grounded energy level discrimination plate positioned within said chamber means at the end of said space opposite to said entrance aperture to intercept selected ones of said particles having a predetermined narrow energy band to thereby divide the remainder of said particles into high and low energy groups.

Claim 11

The device as set forth in claim 6 wherein said particles are electrons.

Claim 12

The device as set forth in claim 6 wherein said screening means are particle transmissive up to 50% for particles approaching said screen within one degree of the tangent to the screen.

Claim 13

The device as set forth in claim 6 wherein said pair of particle attractor means each comprise a conductive plate of low secondary emissive material which acts to attract and hold particles in accordance with the energy of the said particles.

Claim 14

The device as set forth in claim 11 wherein said chamber means includes an exit aperture in said chamber at the end of said space opposite to said entrance aperture and wherein collector means are provided to collect particles having energies falling within the narrow band of energies required for particles to pass through said exit aperture.

Claim 15

The device as set forth in claim 12 wherein said particles are electrons.

Claim 16

A narrow band electrostatic prism device for filtering particles of a selected narrow band of energy from a beam of charged particles comprising: source means for producing a beam of charged particles; chamber means having an entrance aperture for receiving said beam of charged particles into said chamber and an exit aperture angularly displaced from said entrance aperture for exiting selected ones of said particles entering said chamber; electrostatic field forming means mounted within said chamber means for forming an electrostatic field extending in an angular path between said entrance aperture and said exit aperture, said field forming means including a pair of oppositely poled high transmission screening electrode means mounted in spaced apart relationship to form an angular field space extending from said entrance aperture to said exit aperture; a pair of particle attractor means each exhibiting a voltage potential having a polarity opposite to that of the charge of the particles of said beam of charged particles, one of said pair of particle attractor means mounted within said chamber means, exterior to said field space, adjacent one of said high transmission screening electrode means for attracting high energy particles and the other of said pair of particle attractor means mounted within said chamber means, exterior to said field space, adjacent the other of said high transmission screening electrode means for attracting low energy particles; and particle collection means for collecting and detecting particles having energy within the narrow band of energy required to effect traversal of a trajectory within said angular field space to said exit aperture.

Claim 17

A narrow band electrostatic prism device for filtering particles of a selected narrow band of energy from a beam of charged particles comprising: source means for producing a beam of charged particles; chamber means having an entrance aperture for receiving said beam of charged particles into said chamber and an exit aperture angularly displaced from said entrance aperture for exiting selected ones of said particles entering said chamber; electrostatic field forming means mounted within said chamber means for forming an electrostatic field extending in an angular path between said entrance aperture and said exit aperture, said field forming means including a pair of oppositely poled high transmission screening electrode means mounted in spaced apart relationship to form an angular field space extending from said entrance aperture to said exit aperture; a pair of particle attractor means each exhibiting a voltage potential having a polarity opposite to that of the charge of the particles of said beam of charged particles, one of said pair of particle attractor means mounted within said chamber means, exterior to said field space, adjacent one of said high transmission screening electrode means for attracting high energy particles and the other of said pair of particle attractor means mounted within said chamber means, exterior to said field space, adjacent the other of said high transmission screening electrode means for attracting low energy particles; and particle collection means for collecting and detecting particles having energy within the narrow band of energy required to effect traversal of a trajectory within said angular field space to said exit aperture.

Claim 18

An electrostatic prism energy level discriminator for discriminating between the high energy and low energy particles of a beam of charged particles comprising: source means for producing a beam of charged particles; chamber means having an entrance aperture for receiving said beam of charged particlEs into said chamber; electrostatic field forming means mounted within said chamber means for forming an electrostatic field extending in an angular path from said entrance aperture, said field forming means including a pair of oppositely poled high transmission screening electrode means mounted in spaced apart relationship to form an angular field space extending from said entrance aperture; particle interception plate means mounted at the end of said angular path opposite to said entrance aperture so as to intercept particles within a selected narrow energy band; a pair of particle attractor means each exhibiting a voltage potential having a polarity opposite to that of the charge of the particles of said beam of charged particles, one of said pair of particle attractor means mounted within said chamber means, exterior to said field space, adjacent one of said high transmission screening electrode means for attracting high energy particles and the other of said pair of particle attractor means mounted within said chamber means, exterior to said field space, adjacent the other of said high transmission screening electrode means for attracting low energy particles; and a pair of particle collection means for collecting and detecting said particles, one of said pair of particle collection means arranged to collect and detect high energy particles attracted by the said one of said pair of particle attractor means and the other of said particle collection means arranged to collect and detect low energy particles attracted by the said other of said particle attractor means.

Claim 19

An electrostatic prism energy level discriminator for discriminating between the high energy and low energy particles of a beam of charged particles comprising: source means for producing a beam of charged particles; chamber means having an entrance aperture for receiving said beam of charged particlEs into said chamber; electrostatic field forming means mounted within said chamber means for forming an electrostatic field extending in an angular path from said entrance aperture, said field forming means including a pair of oppositely poled high transmission screening electrode means mounted in spaced apart relationship to form an angular field space extending from said entrance aperture; particle interception plate means mounted at the end of said angular path opposite to said entrance aperture so as to intercept particles within a selected narrow energy band; a pair of particle attractor means each exhibiting a voltage potential having a polarity opposite to that of the charge of the particles of said beam of charged particles, one of said pair of particle attractor means mounted within said chamber means, exterior to said field space, adjacent one of said high transmission screening electrode means for attracting high energy particles and the other of said pair of particle attractor means mounted within said chamber means, exterior to said field space, adjacent the other of said high transmission screening electrode means for attracting low energy particles; and a pair of particle collection means for collecting and detecting said particles, one of said pair of particle collection means arranged to collect and detect high energy particles attracted by the said one of said pair of particle attractor means and the other of said particle collection means arranged to collect and detect low energy particles attracted by the said other of said particle attractor means.

Claim 20

The discriminator as set forth in claim 15 wherein said pair of particle attractor means each comprise high transmission screening means respectively positioned between its corresponding particle collector means and said electrostatic field forming means.