The Dynamitron is an

electrostatic Electrostatics is a branch of physics that studies electric charges at rest (static electricity). Since classical times, it has been known that some materials, such as amber, attract lightweight particles after rubbing. The Greek word for amber ...

particle accelerator invented by Marshal Cleland in 1956 at

Washington University in St. Louis Washington University in St. Louis (WashU or WUSTL) is a private research university with its main campus in St. Louis County, and Clayton, Missouri. Founded in 1853, the university is named after George Washington. Washington University is r ...

and manufactured by IBA Industrial (formerly Radiation Dynamics).Cleland, Marshal R., US Patent 2875394A
Voltage multiplication apparatus
filed: 29 October 1956, granted: 24 February 1959 , p.4 It is similar to a Cockcroft-Walton accelerator, using a series

capacitor A capacitor is a device that stores electrical energy in an electric field by virtue of accumulating electric charges on two close surfaces insulated from each other. It is a passive electronic component with two terminals. The effect of ...

diode A diode is a two-terminal electronic component that conducts current primarily in one direction (asymmetric conductance); it has low (ideally zero) resistance in one direction, and high (ideally infinite) resistance in the other. A diode ...

ladder network to generate a high DC voltage on an electrode, which accelerates particles through an evacuated beam tube between the electrode and a target at ground potential. However instead of being powered at one end as in the Cockcroft-Walton, the capacitive ladder is charged in parallel electrostatically by a high frequency oscillating voltage applied between two long half-cylindrical electrodes on either side of the ladder column, which induce voltage in semicircular corona rings attached to each end of the diode rectifier tubes. in combination with an inductor this structure forms a resonant

tank circuit An LC circuit, also called a resonant circuit, tank circuit, or tuned circuit, is an electric circuit consisting of an inductor, represented by the letter L, and a capacitor, represented by the letter C, connected together. The circuit can ac ...

for the

oscillator Oscillation is the repetitive or periodic variation, typically in time, of some measure about a central value (often a point of equilibrium) or between two or more different states. Familiar examples of oscillation include a swinging pendulum ...

providing the voltage, at a frequency of 100 kHz. The alternating voltage across the diodes pumps charge in one direction up the series stack of diodes to the high voltage electrode as in the Cockcroft-Walton circuit. The advantage of this design is that it can produce higher beam currents than the Cockcroft-Walton design, up to hundreds of milliamperes, and the high frequency reduces the ripple on the accelerating voltage. The accelerator stack is inside a tank of pressurized

sulfur hexafluoride Sulfur hexafluoride or sulphur hexafluoride (British spelling) is an inorganic compound with the formula SF6. It is a colorless, odorless, non- flammable, and non-toxic gas. has an octahedral geometry, consisting of six fluorine atoms attached ...

gas for insulation. It can accelerate either electrons or positive ions, and tandem versions have been built. The Dynamitron is made in several models with output energies from 0.5 to 5 MeV and beam power from 50 to 200 kW. Its main use is in industrial irradiation applications; the most common are polymer

crosslinking Cross-linking may refer to *Cross-link In chemistry and biology a cross-link is a bond or a short sequence of bonds that links one polymer chain to another. These links may take the form of covalent bonds or ionic bonds and the polymers ca ...

for production of heat shrink tubing, and shrink wrap plastic film for food packaging, sterilization, and curing of plastic foam and tire components. Around 200 units are in operation, primarily in the US. A number have been installed in university research settings including the University of Birmingham in the UK and Tohoku University in JapanS. Matsuyama, K. Ishii, M. Fujisawa, Y. Kawamura, S. Tsuboi, K. Yamanaka, M. Watanabe, Y. Hashimoto, S. Ohkura, M. Fujikawa, T. Nagaya, K. Komatsu, H. Yamazaki, Y. Kikuchi, Upgrading of the 4.5 MV Dynamitron accelerator at Tohoku University for microbeam and nanobeam applications, Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, Volume 267, Issues 12–13, 15 June 2009, Pages 2060-2064 A modern research application for Dynamitrons is as a high intensity neutron source. They are particularly suited for neutron production via the Lithium (p,n) reaction with potential applications in neutron imaging,

activation analysis Neutron activation analysis (NAA) is the nuclear process used for determining the concentrations of elements in many materials. NAA allows discrete sampling of elements as it disregards the chemical form of a sample, and focuses solely on atomic ...

and

Boron Neutron Capture Therapy Neutron capture therapy (NCT) is a type of radiotherapy for treating locally invasive malignant tumors such as primary brain tumors, recurrent cancers of the head and neck region, and cutaneous and extracutaneous melanomas. It is a two-step proc ...

References

External links

DC Accelerator principles
{{Webarchive, url=https://web.archive.org/web/20101117062148/https://cas.web.cern.ch/cas/Pruhonice/PDF/DC-accel-DB1.pdf , date=2010-11-17
DIAGNOSIS OF DYNAMITRON ACCELERATOR FAULTS THROUGH THE OBSERVATION OF NARROW NUCLEAR RESONANCES
Particle accelerators