US2950390A - Electron lenses - Google Patents
Electron lenses Download PDFInfo
- Publication number
- US2950390A US2950390A US760397A US76039758A US2950390A US 2950390 A US2950390 A US 2950390A US 760397 A US760397 A US 760397A US 76039758 A US76039758 A US 76039758A US 2950390 A US2950390 A US 2950390A
- Authority
- US
- United States
- Prior art keywords
- specimen
- electron
- plate
- pole
- cylindrical
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
- H01J37/02—Details
- H01J37/04—Arrangements of electrodes and associated parts for generating or controlling the discharge, e.g. electron-optical arrangement, ion-optical arrangement
- H01J37/10—Lenses
- H01J37/14—Lenses magnetic
- H01J37/141—Electromagnetic lenses
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F42—AMMUNITION; BLASTING
- F42C—AMMUNITION FUZES; ARMING OR SAFETY MEANS THEREFOR
- F42C13/00—Proximity fuzes; Fuzes for remote detonation
- F42C13/04—Proximity fuzes; Fuzes for remote detonation operated by radio waves
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
- G01N23/22—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by measuring secondary emission from the material
- G01N23/225—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by measuring secondary emission from the material using electron or ion
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
- G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
- G01S13/50—Systems of measurement based on relative movement of target
- G01S13/505—Systems of measurement based on relative movement of target using Doppler effect for determining closest range to a target or corresponding time, e.g. miss-distance indicator
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
- H01J37/02—Details
- H01J37/20—Means for supporting or positioning the objects or the material; Means for adjusting diaphragms or lenses associated with the support
Definitions
- This invention relates to electron lenses and has an important application in X-ray analysing apparatus of the kind described in co-pending application Serial No. 760,472, in which analysis of elements is carried out by bombarding the surface of a specimen with a beam of electrons and examining the wavelengths of the X-rays thereby produced.
- the electron beam shall be of small cross-section and also that there shall be a large electron current in order to obtain a satisfactory X-ray emission.
- the current I is determined by the relationship where C is the spherical aberration coefficient of the lens, is the current density per unit solid angle from the cathode of the electron gun. Hence a small spherical aberration is necessary for a large current and in electron lens arrangements, as hitherto employed, this has usually been achieved by locating the specimen in a strong magnetic field between the pole pieces.
- the main object of the invention is to provide an improved electron lens arrangement in which the difficulties above referred to are substantially avoided or minimised.
- an electron lens arrangement comprises an annular magnet assembly adapted to encircle the beam path concentrically therewith and com-prising axially displaced annular poles of which one pole is formed by the edge of a small aperture in a plate extending transversely across the electron beam path and with the aperture centrally located for the beam and the other pole is formed by a cylindrical plate of large internal diameter relative to the working distance of the specimen and concentric with the beam path and spaced axially from said lateral plate together with means for positioning the specimen in the electron beam path in a region beyond said apertured plate and outside the magnetic structure and in which there is a negligible magnetic field.
- working distance implies the distance between the last working surface of the lens and the focal point at which the specimen is located.
- the working distance of the specimen beyond the structure is large to make it easy to extract the X-ray beam. It will be appreciated that with such an arrangement in which the specimen is located outside the magnetic structure it is possible to extract the X-rays without undue ditficulty as it is not necessary to provide an X-ray passage through the structure and this result is obtained without appreciably increasing the spherical aberration since the diameter of the cylindhical pole is larger.
- the specimen is outside the magnetic field and the transverse apertured plate acts, to a large extent, as a screen between the specimen and the electron lens, it cannot appreciably distort the electron lens field and it is possible to examine specimens of magnetic material, e.g. iron.
- Fig. l is a cross sectional view showing diagrammatically a known form of electron lens for purposes of comparison, whilst Fig. 2 shows an improved electron lens constructed in accordance with the invention, and
- fig. 3 shows one embodiment of the invention.
- the lens shown comprises an annular magnet winding 1 surrounded by a yoke '2, one pole piece is formed by the internal edge 3 of a plate 4 whilst the other pole piece 5 is formed by an internal lip on the end of a cylindrical wall 6; the specimen 7 in such arrangements is located substantially between the pole pieces 3 and 5 and in a region of strong magnetic field to reduce spherical aberration.
- Fig. 2 shows an improved construction in accordance with the invention in which like parts have been given similar references with a prime
- the transverse plate 4 is formed with a small central aperture 8 bordered by the annular pole pieces 3' and that this pole is of reduced section.
- the gap between the pole pieces extends annularly between the pole pieces 5' and the lower face of the transverse plate 4' and the internal diameter of the cylindrical plate 6' is large compared with that of the arrangement of Fig, 1.
- Fig. 3 shows an arrangement in which the specimen 7 is mounted on a rotatable carrier 9 mounted on a spindle 10 extending through the cylindrical casing wall 11 of the apparatus.
- an electron lens arrangement comprising concentric cylindrical plates encircling the electron beam path, an energising winding located in the annular space between said cylindrical plates, at first annular end plate joining corresponding end edges of the cylindrical plates, an edge to the inner cylindrical plate at the opposite end to said annular plate which edge forms a 'firstmagnetic pole, a transverse plate extending across the electronbeam path in spaced relationship with the pole forming the edge of said innercylindrical plate and secured along its periphery to, the correspond ing end of the outer cylindrical plate, said transverse plate having a circular aperture defined by an edge-concentric with the beam path, saidedg'e forming a second magnetic pole face, means for positioning a specimen in the beam path beyond said transverse plate, a cylindrical casing extending axially of the beam path away from said transverse plate and encircling the beam path and specimen and an aperture in said casing adapted to permit X-ra-ys from the specimen to pass out from the
Landscapes
- Engineering & Computer Science (AREA)
- Remote Sensing (AREA)
- Physics & Mathematics (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Radar, Positioning & Navigation (AREA)
- General Physics & Mathematics (AREA)
- Computer Networks & Wireless Communication (AREA)
- Electromagnetism (AREA)
- General Engineering & Computer Science (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Analysing Materials By The Use Of Radiation (AREA)
- Radar Systems Or Details Thereof (AREA)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB28674/57A GB847266A (en) | 1960-12-15 | 1957-09-11 | Improvements relating to electron lenses |
FR846971A FR1283259A (fr) | 1960-12-15 | 1960-12-15 | Dispositif permettant la mesure de la distance de deux objets dont un au moins est mobile |
Publications (1)
Publication Number | Publication Date |
---|---|
US2950390A true US2950390A (en) | 1960-08-23 |
Family
ID=32395580
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US760397A Expired - Lifetime US2950390A (en) | 1957-09-11 | 1958-09-11 | Electron lenses |
US159374A Expired - Lifetime US3140488A (en) | 1957-09-11 | 1961-12-14 | Miss distance indicator |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US159374A Expired - Lifetime US3140488A (en) | 1957-09-11 | 1961-12-14 | Miss distance indicator |
Country Status (5)
Country | Link |
---|---|
US (2) | US2950390A (fr) |
CH (1) | CH364373A (fr) |
DE (2) | DE1096061B (fr) |
FR (1) | FR1203259A (fr) |
GB (1) | GB1004873A (fr) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE1806891A1 (de) * | 1967-11-03 | 1969-06-19 | Nat Res Dev | Einrichtung zur Fokussierung von aus geladenen Teilchen bestehenden Strahlen |
US4209702A (en) * | 1977-07-25 | 1980-06-24 | Kabushiki Kaisha Akashi Seisakusho | Multiple electron lens |
Families Citing this family (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE1265996B (de) * | 1964-05-22 | 1968-04-11 | Dornier System Gmbh | Schatungsanordnung zur Erfassung der Anzahl von Treffern |
DE1428724A1 (de) * | 1964-08-27 | 1969-03-06 | Dornier System Gmbh | Verfahren zum Erfassen von Treffern bzw. vorbeifliegenden Geschossen mittels elektromagnetischer Strahlung |
US3390348A (en) * | 1966-04-28 | 1968-06-25 | Aga Ab | System for generating a signal representing the time delay of a signal patch |
GB1434532A (en) * | 1972-05-03 | 1976-05-05 | Decca Ltd | Multiple frequency continuous wave radars |
FR2204811B1 (fr) * | 1972-10-31 | 1977-04-01 | Thomson Csf | |
SE431253B (sv) * | 1977-08-10 | 1984-01-23 | Microwave & Electronic Syst | System for metning av minimiavstand mellan forsta och andra foremal som ror sig i forhallande till varandra |
DE3215479A1 (de) * | 1982-04-24 | 1988-08-18 | Krupp Atlas Elektronik Gmbh | Verfahren zum bestimmen von zeitspannen |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
SE113186C1 (fr) * | 1941-11-29 | 1945-02-13 | ||
US2440640A (en) * | 1946-11-27 | 1948-04-27 | Research Corp | Electron microanalyzer |
US2849619A (en) * | 1948-10-01 | 1958-08-26 | Siemens Ag | Electron microscope having a multiplespecimen carrier |
-
0
- DE DENDAT1251828D patent/DE1251828B/de active Pending
-
1958
- 1958-09-05 DE DEM38843A patent/DE1096061B/de active Pending
- 1958-09-10 FR FR1203259D patent/FR1203259A/fr not_active Expired
- 1958-09-10 CH CH6380758A patent/CH364373A/de unknown
- 1958-09-11 US US760397A patent/US2950390A/en not_active Expired - Lifetime
-
1961
- 1961-12-11 GB GB44299/61A patent/GB1004873A/en not_active Expired
- 1961-12-14 US US159374A patent/US3140488A/en not_active Expired - Lifetime
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
SE113186C1 (fr) * | 1941-11-29 | 1945-02-13 | ||
US2440640A (en) * | 1946-11-27 | 1948-04-27 | Research Corp | Electron microanalyzer |
US2849619A (en) * | 1948-10-01 | 1958-08-26 | Siemens Ag | Electron microscope having a multiplespecimen carrier |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE1806891A1 (de) * | 1967-11-03 | 1969-06-19 | Nat Res Dev | Einrichtung zur Fokussierung von aus geladenen Teilchen bestehenden Strahlen |
US4209702A (en) * | 1977-07-25 | 1980-06-24 | Kabushiki Kaisha Akashi Seisakusho | Multiple electron lens |
Also Published As
Publication number | Publication date |
---|---|
GB1004873A (en) | 1965-09-15 |
US3140488A (en) | 1964-07-07 |
DE1096061B (de) | 1960-12-29 |
DE1251828B (fr) | |
CH364373A (de) | 1962-09-15 |
FR1203259A (fr) | 1960-01-18 |
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