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DE-102010061178-B4 - Chromatic energy filter

DE102010061178B4DE 102010061178 B4DE102010061178 B4DE 102010061178B4DE-102010061178-B4

Abstract

Energy filter device (1, 23) for focusing and energy filtering the radiation from charged particles (3) generated by a laser target particle accelerator, comprising at least one energy-dependent focusing device (12, 20, 27, 28, 29) configured such that particles of different energies are focused at different locations, and at least one radiation separation device (15, 17, 30, 37) configured such that it does not attenuate some parts of the particle beam and attenuates other parts of the particle beam completely or to a negligible level, wherein the at least one energy-dependent focusing device (12, 20, 27, 28, 29) is arranged in the direction of radiation upstream of the at least one radiation separation device (15, 17, 30, 37) and is configured as a solenoid device.

Inventors

  • Ingo Hofmann

Assignees

  • GSI HELMHOLTZZENTRUM FÜR SCHWERIONENFORSCHUNG GMBH

Dates

Publication Date
20260513
Application Date
20101213

Claims (15)

  1. Energy filter device (1, 23) for focusing and energy filtering the radiation from charged particles (3) generated by a laser target particle accelerator, comprising at least one energy-dependent focusing device (12, 20, 27, 28, 29) configured such that the focusing of particles of different energies takes place at different locations, and at least one radiation separation device (15, 17, 30, 37) configured such that it does not attenuate some parts of the particle beam and attenuates other parts of the particle beam completely or to a negligible level, wherein the at least one energy-dependent focusing device (12, 20, 27, 28, 29) is arranged in the direction of radiation in front of the at least one radiation separation device (15, 17, 30, 37) and is configured as a solenoid device.
  2. Energy filter device (1, 23) according to Claim 1 , characterized by exactly one or exactly two radiation separation devices (15, 17, 25, 30, 37).
  3. Energy filter device (1, 23) according to Claim 1 or 2 , characterized by at least one variable radiation separation device (17, 30) and/or by at least one slidably arranged radiation separation device (17, 30, 37).
  4. Energy filter device (1, 23) according to one of the preceding claims, characterized by a plurality of focusing devices (12, 20, 27, 28, 29) wherein the focusing devices (12, 20, 27, 28, 29) act focusing in different directions.
  5. Energy filter device (1, 23) according to one of the preceding claims, characterized in that in at least one focusing device (12, 20, 27, 28, 29) the energy dependence (13, 14) of the focusing manifests itself as a displacement of the focal point (13, 14), in particular as a displacement of the focal point (13, 14) in the longitudinal direction (11).
  6. Energy filter device (1, 23) according to one of the preceding claims, characterized in that at least one radiation separation device (15, 17, 25, 30, 37) is designed as a section-wise absorber device (15, 17, 25, 30, 37).
  7. Energy filter device (1, 23) according to one of the preceding claims, characterized in that the at least one radiation separation device is designed as an aperture device (17, 25, 30, 37) and/or as an axial absorber device (15), wherein the at least one aperture device (17, 25, 30, 37) and/or the at least one axial absorber device (15) is provided at least partially with obliquely beam-optimized surfaces (26, 31, 38).
  8. Energy filter device (1, 23) according to one of the preceding claims, characterized in that the at least one radiation separation device is designed as an aperture device (17, 25, 30, 37) and/or as an axial absorber device (15), wherein the at least one aperture device (17, 25, 30, 37) and/or the at least one axial absorber device (15) has at least partially a frustoconical (26) and/or a double frustoconical surface (31).
  9. Energy filter device (1, 23) according to one of the preceding claims, characterized in that at least one radiation separation device (15, 17, 25, 30, 37) is designed as a direction-dependent radiation separation device (25, 30, 37), in particular as an angle-direction-dependent radiation separation device (25, 30, 37).
  10. Energy filter device (1, 23) according to one of the preceding claims, characterized by at least one upstream radiation separation device (25) which effects radiation separation (25) with respect to the solid angle range (10) of the radiation (3) entering the energy filter device (1, 23).
  11. Energy filter device (1, 23) according to one of the preceding claims, characterized by at least one radiation scattering device (4, 19) for outgoing radiation (3, 16), which is preferably designed as a scattering foil device (19).
  12. Energy filter device (1, 23) according to one of the preceding claims, characterized by at least one downstream focusing device (20) for the radiation (3, 16) emerging from the energy filter device (1, 23).
  13. Particle radiation source (2, 24), in particular particle radiation source (2, 24) for providing particle radiation (3) with specific energies, comprising at least one target device (7), in particular at least one laser target device (5, 7), and at least one energy filter device (1, 23) according to one of the Claims 1 until 12 .
  14. Method for energy-dependent filtering of charged particle radiation (3), in which the radiation (3) is split using at least one energy-dependent focusing device (12, 20, 27, 28, 29) configured as a solenoid device such that the focusing of particles of different energies takes place at different locations, and subsequently radiation (3) with a desired energy is separated by means of at least one radiation separation device (15, 17, 30, 37) configured such that it does not attenuate some parts of the particle beam and attenuates other parts of the particle beam completely or to a negligible level.
  15. Use of an energy-dependent focusing device (12, 20, 27, 28, 29), which is configured as a solenoid device and such that the focusing of particles of different energies takes place at different locations, for the energy-dependent filtering of radiation (3) of charged particles, wherein the radiation (3) is split using the energy-dependent focusing device (12, 20, 27, 28, 29) and subsequently separated by means of at least one radiation separation device (15, 17, 30, 37), which is configured such that it does not attenuate some parts of the particle beam and attenuates other parts of the particle beam completely or to a negligible level, into radiation (3) with a desired energy.

Description

The invention relates to an energy filter device for charged particle radiation, comprising at least one focusing device and at least one radiation separation device. Furthermore, the invention relates to a particle radiation source, in particular a particle radiation source for providing particle radiation with specific energies, comprising at least one target device, in particular at least one laser target device, and at least one energy filter device. The invention further relates to a method for energy-dependent filtering of radiation, in particular particle radiation, preferably of charged particles. In addition, the invention relates to the use of an energy-dependent focusing device for energy-dependent filtering of radiation, in particular particle radiation. In engineering, it is sometimes necessary in many fields to allow only certain parts of a signal to pass through, while filtering out other parts. Such devices are commonly called filters. For example, it is sometimes necessary to allow only a specific energy range of an input radiation with a broad energy spectrum to pass through the filter, while blocking other energy ranges of the radiation to be processed (filtered). Such a filter device for radiation is typically called an energy filter. Sometimes the term frequency filter is also used, where the energy of radiation can be converted into a frequency, and vice versa, using the so-called de Broglie relation. This applies not only to photon radiation but also, in particular, to particle radiation (also called corpuscular radiation). Particularly in particle accelerator technology, it regularly proves necessary to allow certain energy ranges to pass through an energy filter while filtering out other energy ranges. This applies not only to uncharged particles but especially to charged particles (for example, electrons, protons, and heavy ions, or more generally, charged and/or uncharged leptons and/or hadrons). Particle accelerator technology has meanwhile evolved beyond purely fundamental research and is now routinely used in some fields. Electron welding processes, and especially the medical application of particle radiation, such as in cancer therapy, are just a few examples. Particularly in cancer therapy, ions, especially heavy ions (for example, carbon ions, oxygen ions, neon ions, nitrogen ions and the like), have proven to be extremely advantageous, since such heavy ions exhibit a pronounced Bragg peak, and it is therefore possible to introduce a specific radiation dose not only in a focused x-y direction, but also to limit the dose input to a specific depth range (z direction). Up to now, such particle beams (especially heavy-ion particle beams) have typically been produced using linear accelerators, particle cyclotrons, and/or particle synchotrons. However, the equipment required for such particle synchotrons is relatively complex, so efforts are underway to reduce this complexity. Furthermore, particle beams produced by linear accelerators, cyclotrons, or synchotrons have certain physical disadvantages. Additionally, such accelerators are very large relative to the amount of particles produced and are not very energy-efficient, resulting in correspondingly high installation and operating costs. One proposed alternative method for generating particle beams, particularly heavy-ion beams, involves producing accelerated particles using a laser. In this process, a high-energy laser is directed onto a thin foil. The actual acceleration of the ions takes place directly behind the thin foil, which is irradiated on its front side with laser light at an extremely high power density (typically in the range of 10²¹ watts/ cm² ). The heat energy deposited in the foil thereby causes the ions to accelerate through thermal motion effects. In this proposed accelerator concept, unlike particle synchrotrons or linear accelerators, ions are emitted in a bundle-like pattern from a essentially point-like starting position. Furthermore, an extremely broad spectrum of particle energies is generated. It is therefore desirable to focus the angularly fanned beam of radiation and, in addition, to filter out the usable energies. It would be particularly advantageous if the filtering were variable, thus enabling simple depth modulation when irradiating material (for example, patient tissue). It has been shown that previous concepts for energy filtering of particle radiation generally have major shortcomings, especially when used together with laser target foil particle accelerators. DE10323654A1 describes an energy filtering device that spectrally spreads the radiation generated by a laser-target particle accelerator using scattering foils or magnets and selects the high-energy particles using collimators. DE102007054919B4 discloses an energy matching device for an ion beam of sharply defined energy, wherein the beam is directed by means of a dipole magnet onto a wedge-shaped absorber which attenuates the energy o