Heavy ions are ions of nuclei with mass numbers greater than 4, i.e., after the helium nucleus of the periodic table (atoms that have lost electrons with atomic numbers greater than 2). Examples include carbon 12, neon 22, calcium 45, iron 56, krypton 84, and uranium 238. Heavy ions have begun to apply to radiobiology, diagnostic radiation and radiation therapy. In the radiation treatment of cancer, compared with X-rays, heavy ions in the organism in the line energy transfer value is high, and can accurately control the dose and range, positioning performance is good, the end of the range of the release of energy concentration, so that the effect of killing and injuring the need for irradiation of the local range, and reduce the damage to the surrounding healthy tissues.
Basic introduction Chinese name ：heavy ion Foreign name ：heavy ion Type ：charged particles Composition ：Carbon and neon ions Function ：Radiation Set of fields ：Nuclear medicine, nuclear power reactors Concept, heavy ion nuclear reaction, heavy ion nuclear physics, heavy ion radiotherapy, radiotherapy devices, materials field, value, heavy ion gas pedal, concept Heavy ion refers to the mass number greater than 4 atomic nuclei, that is, the periodic table helium, the nucleus after the (atomic number of Helium). Ions after the nucleus (atoms that have lost electrons with an atomic number greater than 2). Examples include carbon 12, neon 22, calcium 45, iron 56, krypton 84, and uranium 238. Heavy ions have begun to apply to radiobiology, radiation diagnosis and radiation therapy. In the deepening of the basic research of heavy ion nuclear physics, heavy ions in other disciplines have begun to have the application and attention. Heavy ion nuclear reaction A reaction caused by the bombardment of the nucleus of an atom by ions of accelerated mass greater than a particle. Heavy ions are capable of producing a much wider variety of nuclear reactions than light ions, and differ from light ion nuclear reactions in some important respects. The de Broglie wavelength (see wave-particle duality) of the relative motion of heavy ions is very short, typically on the order of only 0.1 femtometers (fm), which is much smaller than the radius of an atomic nucleus, and the typical situation of a heavy-ion collision process can be described by using the orbital image of a classical particle collision.Since the mid-1960s, a variety of super? elements (Z=102-109) and have been used in the study of nuclides far from the β-stability line as well as nuclei in highly excited and high-spin states. From the mid-1960s to the early 1970s, heavy-ion nuclear reactions gradually became the main means of obtaining synthetic hyper? elements. Heavy ions are structured composite particles, and the mechanism of nuclear reactions induced by them is very different from that of light ion nuclear reactions in some important aspects. According to the needs of research, people can also choose a variety of target nuclei and bomb nuclei combination, which is also a unique advantage of heavy ion nuclear reaction. The De Broglie wavelength λ of the relative motion of heavy ions is very short, typically on the order of 1/10 fm, which is much smaller than the diameter of an atomic nucleus; however, for the same bombardment of Th by a 4 MeV proton, λ ≈ 2.25 fm, which is much larger than that of heavy ions. Therefore, the typical situation of heavy-ion collision process can be described by using the orbital image of classical particle collision, and the reaction mechanism of heavy-ion collision process can be categorized according to the collision coefficient b or orbital angular momentum l, i.e., with the decrease of b or l, the interaction of two nuclei occurs from the surface to the interior, and the elastic scattering, inelastic scattering (mainly Coulomb excitation), and the transfer reaction (heavy-ion nuclear reaction) occur in the order of time. In general, elastic scattering, inelastic scattering and transfer reactions are collectively referred to as quasi-elastic scattering), deep inelastic collisions of heavy ions, and full-fusion reactions (sometimes, as b decreases, full-fusion reactions occur first, followed by deep inelastic collisions). Heavy-ion nuclear physics A subdiscipline of atomic nuclear physics. The use of heavy ions accelerated to various energies to bombard the atomic nucleus, the study of nuclear structure and the law of change of motion. This has been an active frontier of atomic nuclear physics for more than 20 years. Heavy ion beams are also used to study the structure and properties of atoms, molecules, and condensed matter. Heavy ion radiotherapy Heavy ion radiotherapy: heavy ion radiation is the sheer point and have the advantages of the proton in the distribution of radiation physics chipping quantity. It also has strong radiobiological effects, with stronger tumor killing effects than protons, especially on photon and proton radiation resistance, such as OO stage, s-stage tumor cells, anaerobic tumor cells and intrinsic radiation resistance tumors, such as melanoma. Taking the most common oxygen-poor tumor cells in tumors as an example, the amount of photons needed to eliminate them is at least 3 grams of unextinguished oxygen-rich cells. And the ability of heavy shepherds to kill oxygen-poor cells early is three times that of photons. Due to the more powerful radiobiological effect of heavy particles, it is a "double-edged sword". If the heavy ion irradiation in normal tissues and organs. Serious radiation damage will also occur. Therefore, it is necessary to apply precise radiotherapy techniques, including repeatable patient position fixation devices, precise tumor localization. Accurate delivery of radiotherapy dose, image-guided radiotherapy, motion control of tumor target area and so on. Make the physical dose distribution and the three-dimensional morphology of the tumor to maintain consistency, to focus the dose on the tumor. And less irradiation of normal tissues and organs of the jji|gastric. In tumor radiotherapy, the main application of radiation is ram ion. The clinical application of heavy ion is mainly carried out in Japan and Germany. Japan's National Institute of Radiological Sciences (National I∞btute ofRadiological Sciences, NIRS) began clinical trials with carbon ion radiotherapy in 1994. From June 1994 to February 2008, NIRS*** treated 3819 tumor patients with carbon particles. Including 4053 tumor lesions, including prostate cancer 762 cases. 550 cases of lung cancer, 53 cases of head and neck tumors, 491 cases of bone and Gan tissue malignant tumors. Primary cancer 307 cases. There were 177 cases of rectal cancer, 128 cases of uterine cancer, and 101 cases of central nervous system tumors. Retinal melanoma 82 cases. Skull base tumor 52 cases, esophageal cancer 53 cases, other tumors 484 cases. The results of clinical treatment showed that radiotherapy was effective in skull base tumors, head and neck tumors, tM:cell lung cancer, primary hepatocellular liver cancer, prostate cancer, bone and soft tissue tumors. In the early stage of lung cancer. Tumor local control rate of liver cancer and prostate cancer has reached comparable efficacy with surgical resection because the treatment is non-invasive and more patients will be able to receive the treatment, such as elderly patients, patients with poor heart, horror, or liver function who cannot receive surgery. So it expands the indications for tumor treatment. Shanghai proton and heavy ion hospital, Fudan University Cancer Hospital heavy ion radiotherapy towel center is under construction, the hospital will provide patients with photon, proton and heavy ion radiotherapy. Proton and heavy ion radiotherapy, the integration of modern photon radiotherapy three-dimensional conformal and intensity-modulated radiotherapy, image-guided radiotherapy technology and proton and heavy ion radiotherapy technology, in particular, the creation of the pen-shaped scanning technology of radiation, can achieve a high degree of tumor radiotherapy fitness. It is the most advanced tumor radiotherapy technology to date, with a high degree of conformity for tumor radiotherapy. Construction of the hospital began in August 2009, and it is expected that proton and heavy ion radiation therapy will begin in the second half of 2013. Radiotherapy Facilities The main large-scale gas pedal is a HIMAC-made facility dedicated to the study of cancer radiotherapy with heavy particle radiation. Gas pedals The main gas pedals are the RFQ gas pedal, a linear gas pedal with a diameter of 0.6 meters and a length of about 7.3 meters, which can accelerate up to 800 keV/nucleon (about 4% of the speed of light) The ALVARE gas pedal, a linear gas pedal with a diameter of 2.2 meters and a length of about 24 meters. It can accelerate up to 6MeV/nucleon (about 11% of the speed of light), The main gas pedal deflection electromagnet, is an electromagnet that deflects heavy particles in order to keep them in synchronized cyclotron orbits, is an alternating current (AC) electromagnet whose magnetic field strength changes with the acceleration energy. Finally, it is through the high-frequency acceleration chamber, after 100,000 revolutions, the maximum energy reaches 800 MeV/nucleon (about 84% of the speed of light) Material field When heavy ions penetrate the film, strong Coulomb interactions with the electrons in the medium, the electrons are peeled off more than the composite probability, so high-speed heavy ions through the medium film will be in the excitation of the highly peeled off state. Measurement of the spectra emitted by the excited ions at different distances behind the film (at different moments after excitation) allows the study of the properties and lifetimes of these excited states (see beam-foil spectroscopy). The suite of heavy-ion beams gives favorable conditions for studying the properties of the inner-shell layer of atoms, which is closely related to astrophysical research. In addition to ion implantation techniques used in the fabrication of semiconductor devices and the surface treatment of materials (e.g., to change the surface hardness, coefficient of friction, and corrosion resistance of materials), heavy-ion beams can be used to change the properties of thin films, and to fabricate nuclear thin-film filters with pore diameters ranging from a few nanometers to a few tens of micrometers. Simulation studies of irradiation damage to heat-releasing components and structural materials in fission or fusion reactors using heavy ion beams are far more efficient than other methods. Value Medical Value of Heavy Ion Radiation Heavy ion radiation for the treatment of oncological cancers is a contemporary and recognized method of advanced and effective radiotherapy, which is determined by the unique physical and biological properties of heavy ion rays. The physical properties are such that carbon ions, like other heavy charged particles, have the property of inverting the dose distribution. Heavy ions lose energy when penetrating matter primarily through collisions with electrons outside the nucleus of the target atom, and the chance of such collisions increases as the energy of the ion decreases. In most of the range of ions into the human body, the huge initial energy to make ions through the tissue speed is very fast, and thus the loss of energy is small, the formation of a relatively low-energy ping area; at the end of the range, with the loss of energy, the ion movement slows down, and the target electron collision rate increases, and eventually at the end of the range to form a steep high dose (energy loss) peak, that is, Bragg peak, after which the dose falls rapidly. The depth of the Bragg peak can be adjusted by changing the initial energy of the incident ions. During treatment, the broadened Bragg peak is precisely adjusted to encompass the entire tumor target area, so that the surrounding normal tissues are irradiated with only a small dose. By utilizing the electrically charged nature of the heavy ions, we can achieve "conformal therapy" in which the beam is guided by the grid scanning technique to perform precise tomography of the tumor. In addition, heavy ions scatter less than protons and photons, which is advantageous for precise dose distribution. Biologically, heavy ion rays directly damage DNA double strands irreparably, while heavy ion rays also damage DNA double strands of anoxic cancer cells, which are not sensitive to ordinary photon rays, resulting in irreparable damage. Based on these two characteristics, it can be seen that the medical value of heavy ion radiation therapy is very great, and it will become one of the main treatments for cancerous tumors in the future. Heavy ion gas pedal An ion gas pedal is a gas pedal used to accelerate ions heavier than alpha particles, or sometimes protons. Heavy ion gas pedals can accelerate large quantities of heavy ions to very high speeds, even close to the speed of light. High-speed heavy ions form heavy ion beams, which are used to conduct research in heavy ion physics. Most of the new and renovated heavy ion gas pedals in the world are isochronous cyclotrons (i.e., sector-focused cyclotrons). The second is the tandem electrostatic gas pedal. In order to obtain higher energy, many newly built installations use two or more gas pedals in series. To form a heavy ion gas pedal system, some are tandem electrostatic gas pedals injected into cyclotrons or linear gas pedals, others are two cyclotrons in series. In order to transport the beam from the injector to the main gas pedal, a beam transport system is required to transform the injector elicited beam in an appropriate shape to suit the beam requirements of the main gas pedal. In addition, in order to reduce the ion loss due to charge exchange, the gas pedal and the beam transport system require a high degree of straightness, generally around 1×10-7 Torr. There should be a charge analysis device on the transport line. The structure of the heavy ion gas pedal determines that its commissioning and operation is more complicated, generally should be equipped with an automatic control system to control the commissioning and operation, of course, in the gas pedal and on the transport line of the beam current diagnostic equipment is essential. The country's first self-developed medical heavy ion gas pedal successfully out of the beam. This means that heavy ion radiation therapy for tumor patients will no longer rely on foreign technical equipment This medical heavy ion gas pedal is located in Wuwei City, Gansu Province, and in May 2012 began development. At present, it has realized the carbon ion beam acceleration of 400 mega electron volts per nucleon and nonlinear **** vibration slow elicitation, which has reached the design index. The equipment can be used for heavy ion radiation therapy for tumor patients, especially difficult, inappropriate for surgery, the use of other treatments prone to recurrence of tumor types.