|Products||Model Number||Spec Sheet||References|
|B-dot probes||M1-B-Single||Diagnostics-Magnetics-Single||References||Get a Quote »|
|Linear arrays||M1-B-Array||Diagnostics-Magnetics-Array||References||Get a Quote »|
|Rogowskis||M1-R||Diagnostics-Magnetics-Rogowski||References||Get a Quote »|
|Rogowskis for banks||M1-R-Air||Request spec sheet||References||Get a Quote »|
|Insitu calibration jig||M1-C-IS||Request spec sheet||References||Get a Quote »|
|Calibration jigs||M1-C||Request spec sheet||References||Get a Quote »|
|Insertable rogowskis||M1-R-Vac||Diagnostics-Magnetics-Rogowski||References||Get a Quote »|
|Flux loops in Air||M1-FL-Air||Request spec sheet||References||Get a Quote »|
|Flux loops in a Vacuum||M1-FL-Vac||Request spec sheet||References||Get a Quote »|
|Electrostatic||Model Number||Spec sheet||Reference|
|Voltage monitors (HV, voltage dividers)||E1-Vdiv||Request spec sheet||Electrostatic References||Get a Quote »|
|Langmuir probe – static||E1-L-[# of tips]||Diagnostics-Electrostatic-Langmuir||Electrostatic References||Get a Quote »|
|Langmuir probe – reciprocating||E1-L-R||Diagnostics-Electrostatic-Langmuir||Electrostatic References||Get a Quote »|
|Retarding Grid Energy Analyzers||E1-RFA||Diagnostics-Electrostatic-RFEA||Electrostatic References||Get a Quote »|
|Ball pen probe||E1-Bpp||Request spec sheet||Electrostatic References||Get a Quote »|
|Faraday cup||E1-FC||Request spec sheet||BElectrostatic References||Get a Quote »|
|Mach probes||E1-M||Request spec sheet||Electrostatic References||Get a Quote »|
|Refractive index||Model Number||Spec sheet||References|
|CO2 Interferometer||R1-CO2||Request spec sheet||Refractive Index References||Get a Quote »|
|HeNe interferometer||R1-HeNe||Diagnostics-Refractive-HeNe||Get a Quote »|
|Microwave interferometer||R1-M||Diagnostics-Refractive-Microwave||Get a Quote »|
|Polarimetry||R1-P||Request spec sheet||Refractive Index References||Get a Quote »|
|mmWave Reflectometer||R1-R||Request spec sheet||Get a Quote »|
|Fiber-Coupled Interferometer||R1-F||Request spec sheet||Get a Quote »|
|Fiber-Coupled, Two-Color Interferometer||R1-F-2C||Request spec sheet||Get a Quote »|
|Scattering||Model Number||Spec sheet||References|
|Profile Thomson Scattering-YAG||S1-T-YAG||Request spec sheet||Scattering References||Get a Quote »|
|Profile Thomson Scattering-RUBY||S1-T-RUBY||Request spec sheet||Scattering References||Get a Quote »|
|Radiation||Model Number||Spec sheet||References|
|Photodiode bolometer||SP1-B||Request spec sheet||Get a Quote »|
|3 channel filtered bolometer array||SP1-B-3||Request spec sheet||Get a Quote »|
|1 channel thermistor||SP1-B-T||Request spec sheet||Get a Quote »|
|Charge exchange particle neutral analyzer||SP1-NPA||Request spec sheet||Get a Quote »|
|Visible spectrometer||SP1-SP-VIS||Request spec sheet||Get a Quote »|
|Hard X-ray||Request spec sheet||Get a Quote »|
|VUV monochrometers||SP1-SP-VUV||Request spec sheet||Get a Quote »|
|H-alpha array||SP1-SP-Ha||Request spec sheet||Get a Quote »|
|TV cameras||SP1-SP-TV||Request spec sheet||Get a Quote »|
|Microwave Imaging Reflectometer||Request spec sheet||Get a Quote »|
|Scintillator||SP1-S||Request spec sheet||References||Get a Quote »|
|Neutral Particle Analyzer||Request spec sheet||References||Get a Quote »|
|Gas||Model Number||Spec sheet||References|
|Residual gas analyzer||RGA-1||Request spec sheet||Get a Quote »|
WSI has nearly a decade of experience designing and manufacturing diagnostics for plasma experiments. Browse our product listings to the left or download a flyer (pdf).
Recently WSI was awarded a Phase I and Phase II SBIR to examine the role that Additive Manufacturing can play in the development of plasma diagnostics.
During the last 50 years, plasma diagnostics have matured into a standard set that now measure most of the dominant parameters needed to understand plasma confinement. New diagnostics are being developed that allow new parameters to be measured. However, when presented with the opportunity to start a new facility or maintain an existing facility with failures in diagnostics occurring relatively frequently, the recourse is to utilize techniques and technologies dating back 50 years or more, resulting in expensive, large and often time-consuming diagnostic development activities.
A principal cost associated with any new fusion system is the subsystem comprising all of the measurements needed to ensure that the plasma is reaching the temperature, density and confinement time needed for fusion conditions. This `diagnostic' subsystem relies on technology that is decades old, and any custom system is expensive. Some diagnostic components are known to fail regularly (such as plasma-facing mirrors on larger devices), and solutions for their cleaning or replacement are not straightforward to implement. Additive manufacturing with vacuum compatible and plasma-compatible materials could therefore significantly impact the costs of the diagnostic subsystems, allowing in some possible cases for in-situ manufacture in vacuum, thereby reducing costs and shortening time-lines for commercial deployment.
Diagnostic costs are also prohibitive for entry into fusion research: typically a magnetic system can cost several thousand dollars, and usually custom made. Open source designs are now eliminating design costs - optical mount components are now available free for download and a few cents for printing. We provide magnetic system components on our website for download and printing already. Having a complete set of diagnostic designs available to academics and students will significantly impact development costs and time, and significantly reduce barriers to entry into plasma physics as a field.
Fostering a community of 'open-source diagnosticians' can only help to improve the development of fusion technology and expedite transfer of technology to areas of high tech industry. All of the diagnostic designs (not printer technology) that we will develop during the Phase I SBIR will therefore be offered as open-source on one of the available forums (or through our website). The designs will be available to serious academic studies and a wider sphere of high school educational projects.
For magnetic fusion energy (MFE) systems, measurements of the magnetic field and associated current are the primary diagnostic interest. Faraday's law states that a time-varying magnetic field, B(t), will induce an electric field, E(t), in a loop of wire: ∇×E = -dB/dt. For n loops of wire with cross-sectional area, A, the resulting electric potential is φ(t) = nAdB/dt (where B is the component of B along the axis of the loops). Measuring the voltage produced by such a coil will therefore give the time- variation of B, which after integration (numerical or passive) will yield B(t). Magnetic probes typically comprise many loops of magnet wire wound around a plastic form. These coils are commonly mounted around the perimeter of an experiment and designed either to measure either the slow or fast variations in B (so-called equilibrium coils or fluctuation coils). Coils can also be wound to be sensitive to multiple orthogonal components of B, measuring all at the same time. A similar type of probe called a Rogowski coil measures the time-variation of the current passing through it, which is integrated to find I(t). We have engineered various ultra-high vacuum (UHV) compatible magnetic probes for various purposes, including single coils and arrays. We have also developed Helmholtz coil arrays used to calibrate these coils either in-situ or on a bench. A good reference for magnetic probes is Hutchinson's Principles of Plasma Diagnostics. References for specific applications can be found in Magnetics References.When requesting a quote for a magnetic diagnostic, please consider the following:
Download this coil for 3D-Printing (.stp file)
A Fundamental technique for measuring the properties of plasmas is the use of electrostatic probes, most notably the Langmuir probe, Mach probe, and retarding field analyzer (RFA). These probes are inserted into the plasma and thus allow local measurement of several plasma properties. The Langmuir probe measures the electron energy, temperature, and density and comes in single, double, and triple tip configurations, which have various effects on the plasma. Some of these configurations are able to measure the floating potential and/or plasma potential. A Mach probe is used to measure the ion flow velocity. Retarding field analyzers can measure the ion or electron energy and temperature in specific directions. Each electrostatic probe configuration has its advantages and disadvantages and the scientists at WSI can help you decide which probe is right for you. Two excellent references for electrostatic probes are Hutchinson's Principles of Plasma Diagnostics and Noah Hershkowitz's chapter in Plasma Diagnostics: Discharge Parameters and Chemistry. References for specific applications of each type of probe are provided in the sections below.When requesting a quote for an electrostatic diagnostic, please consider the following:
Available in Single, Double, Triple, or Quad tip configurations. Built for UHV environments. Probe size customizable depending on plasma parameters. Reciprocating probes available. Flat probes also available.
The refractive index of a plasma is a robust indicator of the electron density. Interferometers are commonly used to take a chord-averaged measurement of the refractive index, thereby measuring the density along the beam line. An interferometer is favored for its non-perturbing measurement, at the expense of point resolution. Interferometers are often deployed in sets, sampling several chords to build up profile information for the target plasma. Woodruff Scientific provides interferometers in microwave, infrared (CO2), and visible (HeNe) wavelengths to meet your specifications for sensitivity range and vibration tolerance. Density profile information can also be recovered through additional refractive-index diagnostics such as reflectometry (in which the beam is reflected by a surface at the cutoff density) and refractometry (in which the deflection or spread of the transmitted beam is used to infer the density profile). Finally, one can also use the difference in refractive index between left and right circularly polarized waves in a polarimeter to achieve a chord-averaged measurement of the magnetic field component parallel to the beam. An excellent reference for refractive index diagnostics is Hutchinson's Principles of Plasma Diagnostics 2nd Edition.
Fiber-coupled interferometers are very flexible and robust systems, often allowing for lines of sight to be quickly changed without the need for optical realignment.
This two-color system provides vibration compensation in addition to the flexibility and robustness of fiber-coupled systems.
Over time, we plan to develop a whole range of mechanical components for use in our diagnostics, passing on cost savings to customers in the diagnostics. It is also possible that we can design the entire optical system as a single monolithic structure to be printed with alignment built-in. Check back in the coming months as we add more information here, and to our thingiverse pages.
Download files ready for 3D-printing: Beam splitter Mount (for 40mm cube beam splitter)
Download files ready for 3D-printing: Laser Mount (uses 1/4 20 nuts and screws)
Scattering of electromagnetic radiation from the plasma is a non-perturbing method of determining detailed information about the electron distribution function, and sometimes of the ions. Excellent references for Thomson scattering include Sheffield's Plasma Scattering of Electromagnetic Radiation 2nd Edition
Line radiation from the plasma due to bound state transitions of the electrons can yield information about the power losses and impurity concentrations, and also about the velocities of impurities. An excellent secondary reference summarizing the physics is Hutchinson's Principles of Plasma Diagnostics 2nd Edition
Neutral particles are able to escape the confining magnetic field since they are not charged. It is also possible to use neutral particles as probes, which then relies on radiation of some other sort from the plasma for diagnosis. An excellent resource for neutral particle analysis is Hutchinson's Principles of Plasma Diagnostics 2nd Edition
Neutrons escape readily from fusion plasmas, generated in the fusion of deuterium and tritium. Neutron diagnostics can provide information about the rate and also temperature of the fusion plasma. Primary reference for neutron detection is Harvey and Hill's 1979 article Scintillation detectors for neutron physics research