# US 2014/0153699 A1 · Beam Forming Apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0153699 A1 - Document ID: US20140153699A1 - Status: Published application - Kind: A1 - Application number: 14/047,583 - Filed: 2013-10-07 - Published: 2014-06-05 - Earliest claimed: 2010-03-14 - Assignees: Rapiscan Systems, Inc. - Applicants: Rapiscan Systems, Inc. - Inventors: Joseph W. Kaminski - Web page: https://patentgrep.com/patent/US20140153699A1 ## CPC - G21K 1/043: {changing time structure of beams by mechanical means, e.g. choppers, spinning filter wheels} - G01T 1/20: with scintillation detectors - G01V 5/222: measuring scattered radiation - G21K 1/046: {varying the contour of the field, e.g. multileaf collimators} - G21K: HANDLING OF PARTICLES OR IONISING RADIATION NOT OTHERWISE PROVIDED FOR; IRRADIATION DEVICES; GAMMA RAY OR X-RAY MICROSCOPES - G01T: MEASUREMENT OF NUCLEAR OR X-RADIATION (radiation analysis of materials, mass spectrometry G01N23/00; tubes for determining the presence, intensity, density or energy of radiation or particles H01J47/00) - G01V: GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS (means for indicating the location of accidentally buried, e.g. snow-buried, persons A63B29/02) ## Abstract The present specification discloses a beam chopping apparatus, and more specifically, a helical shutter for an electron beam system that is employed in radiation-based scanning systems, and more specifically, a beam chopping apparatus that allows for variability in both velocity and beam spot size by modifying the physical characteristics or geometry of the beam chopper apparatus. The present specification also discloses a beam chopping apparatus which provides a vertically moving beam spot with substantially constant size and velocity to allow for substantially equal illumination of the target. In addition, the present specification is a beam chopping apparatus that is lightweight and does not cause an X-ray source assembly employing the beam chopper to become heavy and difficult to deploy. ## Claims ### Claim 1 An X-ray apparatus comprising: An X-ray source for emitting X-ray radiation; and A beam chopping apparatus coupled to said X-ray source, wherein said beam chopping apparatus is adapted to receive said X-ray radiation and form a moving beam spot having a frequency, wherein said beam frequency is substantially constant. ### Claim 2 (depends on 1) The X-ray apparatus of claim 1 wherein said beam chopping apparatus comprises a hollow cylinder having at least one helical aperture. ### Claim 3 (depends on 1) The X-ray apparatus of claim 1 wherein said beam chopping apparatus comprises a hollow cylinder having at least two helical apertures. ### Claim 4 (depends on 3) The X-ray apparatus of claim 3 wherein said beam has a linear scan velocity and wherein said linear scan velocity is varied by modifying a pitch and roll of at least one of said helical apertures. ### Claim 5 (depends on 3) The X-ray apparatus of claim 3 wherein said beam has a linear scan velocity and wherein said linear scan velocity is kept constant by modifying a pitch and roll of at least one of said helical apertures. ### Claim 6 (depends on 3) The X-ray apparatus of claim 3 wherein said beam has a spot size and wherein said spot size is varied by modifying an aperture width of at least one of said helical apertures. ### Claim 7 (depends on 3) The X-ray apparatus of claim 3 wherein said beam has a spot size and wherein said spot size is kept constant by modifying an aperture width of at least one of said helical apertures. ### Claim 8 (depends on 2) The X-ray apparatus of claim 2 further comprising a motor for rotating said cylinder. ### Claim 9 (depends on 8) The X-ray apparatus of claim 8 further comprising a controller for dynamically modifying a rotation speed of said cylinder to achieve a predetermined scan velocity. ### Claim 10 (depends on 9) The X-ray apparatus of claim 9 wherein said rotation speed is equal to or less than 80,000 rpm. ### Claim 11 (depends on 8) The X-ray apparatus of claim 8 wherein said beam has a scan velocity and a spot size and wherein scan velocity and spot size can be modified without varying a speed of said motor. ### Claim 12 (depends on 1) The X-ray apparatus of claim 1 wherein said beam chopping apparatus comprises a hollow cylinder having at least two helical apertures, each having a length and an aperture width along said length and wherein said aperture width narrows along length. ### Claim 13 (depends on 1) The X-ray apparatus of claim 1 wherein said beam chopping apparatus comprises a hollow cylinder having at least two helical apertures, each having a length and an aperture width along said length and wherein said aperture width increases along length. ### Claim 14 An X-ray apparatus comprising: An X-ray source for emitting X-ray radiation; and A beam chopping apparatus coupled to said X-ray source, wherein said beam chopping apparatus is adapted to receive said X-ray radiation and form a moving beam spot having a velocity, wherein said beam velocity is substantially constant. ### Claim 15 An X-ray apparatus comprising: An X-ray source for emitting X-ray radiation; and A beam chopping apparatus coupled to said X-ray source, wherein said beam chopping apparatus comprises a hollow cylinder with a first end and a second end defining a length of said cylinder and at least one helical aperture extending substantially along said length, wherein said cylinder is adapted to receive said X-ray radiation and emit said X-ray radiation through said helical aperture. ### Claim 16 (depends on 15) The X-ray apparatus of claim 15 wherein said X-ray radiation passes through the helical aperture to produce a beam spot projection pattern, wherein said beam spot projection pattern comprises a beam spot moving vertically with a substantially constant velocity in a plane perpendicular to a plane of the X-ray source. ### Claim 17 (depends on 16) The X-ray apparatus of claim 16 wherein said beam spot projection pattern comprises a beam spot moving vertically with a substantially constant velocity in a plane parallel to a plane of the beam chopping apparatus. ### Claim 18 (depends on 17) The X-ray apparatus of claim 17 wherein said beam spot provides substantially equal illumination of a target object. ### Claim 19 (depends on 15) The X-ray apparatus of claim 15 wherein said beam spot is trapezoidal. ### Claim 20 (depends on 15) The X-ray apparatus of claim 15 wherein said helical aperture has a width that is more narrow at the second end relative to said first end.