US3030506A - X-ray shadow microscope - Google Patents

X-ray shadow microscope Download PDF

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Publication number
US3030506A
US3030506A US829252A US82925259A US3030506A US 3030506 A US3030506 A US 3030506A US 829252 A US829252 A US 829252A US 82925259 A US82925259 A US 82925259A US 3030506 A US3030506 A US 3030506A
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US
United States
Prior art keywords
electron
astigmatism
optical system
electrons
magnetic
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
Application number
US829252A
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English (en)
Inventor
Poole Jan Bart Le
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
US Philips Corp
North American Philips Co Inc
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US Philips Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by US Philips Corp filed Critical US Philips Corp
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Publication of US3030506A publication Critical patent/US3030506A/en
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    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21K—TECHNIQUES FOR HANDLING PARTICLES OR IONISING RADIATION NOT OTHERWISE PROVIDED FOR; IRRADIATION DEVICES; GAMMA RAY OR X-RAY MICROSCOPES
    • G21K7/00—Gamma- or X-ray microscopes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J35/00—X-ray tubes
    • H01J35/02—Details
    • H01J35/14—Arrangements for concentrating, focusing, or directing the cathode ray
    • H01J35/147—Spot size control

Definitions

  • An X-ray shadow microscope is a device comprising an X-ray tube in which the electrons are concentrated into a very small focal spot.
  • An adjustable electron-optical system serves to concentrate the beam of electrons.
  • the size of the focal spot found with the aid of the image on the fluorescent screen has not yet been reduced to the extreme minimum.
  • the X-ray tube of the X-ray shadow microscope comprises, in addition to the electron-optical system, a magnetic astigmatism-correcting element hereinafter referred to as magnetic stigmator and an electrostatic astigmatism-correcting element hereinafter referred to as electrostatic stigmator, the astigmatisms of which can be adjusted separately in value and direction and which are traversed both by electrons emerging from the cathode towards the focal spot and by secondary electrons emerging from the focal spot and travelling in the opposite sense, the electrostatic stigmator correcting the resulting astigmatism of the electron-optical system and of the magnetic stigmator.
  • the operation of the electron-optical system together with the two stigmators is based upon the fact that the astigmatism of ythe electron-optical system is different for the forward and backward rays. Consequently, if the energization is adjusted so that a small focal line lies on the target, such is not the case when this line is reproduced back. The focal line is thus reproduced with lack of definition and no longer recognizable as such due to the finite dimensions of the image proper.
  • the focal line is made visible and then the astigmatism corrected.
  • advantage is taken of the fact that the effect of a magnetic stigmator inverses its polarity with the direction of movement of the electrons, whereas such is not the case with the electric stigmator.
  • the wall of the X-ray tube is constituted by a glass tube 1 and a metallic cylinder 2. These parts are joined by sealing at 3.
  • the base 4 of glass tube 3 has a reentrant part 5, into which fits the end 6 of a high-tension cable having current conductors 7 which are led through a transverse Wall 8 provided in re-entrant part 5, the Wall 8 closing the aperture and carrying a source of rays 9, constituted by a thermionic cathode, and a focussing elecfrode 10.
  • the latter has a small aperture l1 to allow passage of the electrons emitted by the thermionic cathode.
  • the base 4 also contains a lead-through device l2 for a support 13 of a fluorescent screen 14 which is arranged inside the wall 8.
  • the axis of the beam of electrons and the perpendicular to the centre of the fluorescent screen are deflected from the axis of the X-ray tube at the same angles to meet at a point on this axis which is the centre of a magnetic transverse field having its lines of force at right angles to the plane in which the three directions are located.
  • One of the poles of a magnet 15, between which the magnetic transverse field occurs, is shown.
  • the pole which is not shown is located in front of the surface of the beam.
  • the magnetic ltransverse field brings about deflection of the paths of the electrons emerging from the source of electrons and deflections, in the same sense of rotation, of the electrons travelling in the opposite sense.
  • the metal cylinder 2 has an end wall 16 provided with an aperture 17 which is closed by means of a thin metallic window 18.
  • the cylinder 2 contains an electron-optical system which permits of focussing the paths of electrons into a very small focal spot on metal window 18. X-rays are emitted from this focal spot in all directions.
  • the electron-optical system comprises three metal plates 19, 20, 21, which are arranged with small spacings. The plates are provided with apertures 22 23, 24concentrically of the axis of the tube, to allow passage of the ray of electrons.
  • the outer plates 19 and 21 may be connected to the wall of the cylinder, plate 26 being insulated from the wall and the adjacent plates by means of a ring 26 of insulating material. It is possible to apply to plate 20 a potential suitable for focussing the rays of electrons by rneans of a connecting wire 25, which is led through lthe wall in an insulated manner.
  • Electrons return from the window in a direction opposite to that of the electrons travelling to the target through the electron-optical system and are concentrated onto the fluorescent screen 14.
  • the electron-optical system has astigmatism, a corresponding image of that produced on metal window 18 is not obtained on fluorescent screen 14.
  • rods 27 of magnetic material Both the forward and backward electrons traverse the field produced between the pole pieces.
  • the rods may be provided with energizing coils 28 arranged outside the Wall 2 of the X- ray tube around the magnetic rods.
  • the rods 27 are magnetically separated from the wall by means of small rings 29 of non-magnetic material.
  • Eight poles are provided in the magnetic stigmator so that the value and the direction of the added astigmatism are electrically adjustable. It is alternatively possible to utilize other known magnetic stigmators, for example a quadripole having poles which are rotatably arranged about the common axis.
  • a brightly illuminated spot on the luminescent screen indicates that the electron-optical system is exactly adjusted to the Window 18 and that the Surface between the source of rays and the system in which the beam has its smallest cross-section is reproduced.
  • astigmatism it is possible to modify the image on the fluorescent screen by energization of the magnetic stigmator and variation of the Value and directionV of the astigmatism thusV added.
  • Proper adjustment of the s'tigmatorY makes the astigmatism of the electron-optical system visible when the image has its maximum deviation from the circular ashape.
  • the electrostatic stigmatoi may be switched on, which comprises eight electrodes 30 which surround symmetrically the axis of the electron beam and are se'- cured to supporting rods 31.
  • the rods 31 also serve for the supply of the potentials and for this purpose are VledY in an insulated manner through the Wall 2 of the cylinder. Glass beads 32 sealed in the wall 2 may serve for insulation.
  • the operation of such a stigmator is known and provides the possibility ofcorrecting the astigmatism made perceptible in the manner above described.
  • the invention is also applicable to an-X-ray tube comprising a magnetic electron-optical system, While in addition the two stigmators may be interchanged or positioned on the same side in the vicinity of the electron-optical system. These modifications do not inuence the elect envisaged by the' invention.
  • An X-ray shadow microscope comprising an envelope, an electron beam source within said envelope, a' target electrode, an electron-optical system for'focu'ssin'g electrons infsaid beam into a small focal spot on the target electrode for producing X-rays therefrom, ⁇ a uor'es'cent screen within said envelope and positioned to receive a beam of secondary electrons emitted from the focal spot, an" adjustable magnetic electron-beam astigmatism-correcting element disposed in the path of the electronbeam for partially correcting astigmatism in the electron beam produced by the electroni-optical focussingsystem, and an adjustable electrostatic electron beam astigmatism-correcting element disposed in the path of the electron beam for correcting the resultant astigmatism of the electron-optical system and the magnetic astigmatism-correcting element, the two astigmatism-correcting elements being positioned to correct astigmatism in the electron-beam traversing the electron-optical system and the beam of secondary electrons emitted
  • An X-ray shadowrmicroscope as claimed in claim l in which the electron-optical system comprises a plurality of plates provided with coaxial apertures concentric with the electron beam and means to apply potentials to lsaid plates to thereby focus the electrons inthe beam.
  • An X-ray shadow microscope as claimed-in claim 6 in which the electrostatic astigmatism-correcting member comprises la plurality of electrodes coaxial with and surrounding'the electron beam.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
  • Analysing Materials By The Use Of Radiation (AREA)
US829252A 1958-09-13 1959-07-24 X-ray shadow microscope Expired - Lifetime US3030506A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL231359 1958-09-13

Publications (1)

Publication Number Publication Date
US3030506A true US3030506A (en) 1962-04-17

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ID=19751345

Family Applications (1)

Application Number Title Priority Date Filing Date
US829252A Expired - Lifetime US3030506A (en) 1958-09-13 1959-07-24 X-ray shadow microscope

Country Status (6)

Country Link
US (1) US3030506A (es)
CH (1) CH375544A (es)
ES (1) ES251987A1 (es)
FR (1) FR1235118A (es)
GB (1) GB935904A (es)
NL (1) NL108506C (es)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11145481B1 (en) * 2020-04-13 2021-10-12 Hamamatsu Photonics K.K. X-ray generation using electron beam

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2547994A (en) * 1947-03-13 1951-04-10 Csf Electronic microscope
US2580675A (en) * 1947-06-26 1952-01-01 Csf Correction device for microscopes of the reflection mirror type
GB723772A (en) * 1948-10-15 1955-02-09 Siemens Ag Improvements in or relating to electron microscopes
US2802111A (en) * 1955-05-11 1957-08-06 Rca Corp Electron microscope alignment device
US2866113A (en) * 1952-10-07 1958-12-23 Cosslett Vernon Ellis Fine focus x-ray tubes
US2877353A (en) * 1954-07-14 1959-03-10 Gen Electric X-ray microscope
US2939954A (en) * 1957-02-16 1960-06-07 Philips Corp X-ray shadow microscope

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2547994A (en) * 1947-03-13 1951-04-10 Csf Electronic microscope
US2580675A (en) * 1947-06-26 1952-01-01 Csf Correction device for microscopes of the reflection mirror type
GB723772A (en) * 1948-10-15 1955-02-09 Siemens Ag Improvements in or relating to electron microscopes
US2866113A (en) * 1952-10-07 1958-12-23 Cosslett Vernon Ellis Fine focus x-ray tubes
US2877353A (en) * 1954-07-14 1959-03-10 Gen Electric X-ray microscope
US2802111A (en) * 1955-05-11 1957-08-06 Rca Corp Electron microscope alignment device
US2939954A (en) * 1957-02-16 1960-06-07 Philips Corp X-ray shadow microscope

Also Published As

Publication number Publication date
GB935904A (en) 1963-09-04
CH375544A (de) 1964-02-29
ES251987A1 (es) 1960-01-01
NL108506C (es)
FR1235118A (fr) 1960-07-01

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