The Varadis RADFET is a microelectronic chip, specially engineered to be sensitive to high energy (ionising) radiation. The RADFETs are small, robust, require no power to detect radiation, can easily be integrated into electronic systems, and are cost effective.
Varadis RADFET VT01
400nm RADFET in Six Lead SOT-23 Plastic Package
For doses between 1 cGy (1 rad) and 1 kGy (100 krad)
RADFET is a discrete p-channel MOSFET optimized for radiation sensitivity. RADFETs are sensitive to ionizing radiation: gamma rays, X-rays, and protons.
The critical region of the RADFET is its gate oxide. Through generation and trapping of radiation-induced charges in the gate oxide, radiation exposure changes the output voltage of the RADFET and this change is related to the radiation dose. The RADFET response is non-linear and a pre-recorded calibration curve is used to read the dose. The read-out is done by forcing a DC current (in the range of 10s of μA) into the device and measuring the DC voltage (in the range of 0.5 to ~8 Volts).
Varadis RADFET VT02
400nm RADFET in Eight Lead Ceramic Side Braze Package
For doses between 1 cGy (1 rad) and 1 kGy (100 krad)
RADFET is a discrete p-channel MOSFET optimized for radiation sensitivity. RADFETs are sensitive to ionizing radiation: gamma rays, X-rays, and protons.
The VT02 is used by organisations such as the European Space Agency and a number of other space agencies across the globe. The VT02 is hermetically sealed and slightly larger than the plastic version.
The critical region of the RADFET is its gate oxide. Through generation and trapping of radiation-induced charges in the gate oxide, radiation exposure changes the output voltage of the RADFET and this change is related to the radiation dose. The RADFET response is non-linear and a pre-recorded calibration curve is used to read the dose. The read-out is done by forcing a DC current (in the range of 10s of μA) into the device and measuring the DC voltage (in the range of 0.5 to ~8 Volts).
Important Information: The VT01 & VT02 RADFETs have a large dynamic range, from 1 cGy (1 rad) to 1 kGy (100 krad). To fully understand capabilities and limitations of these products, please review datasheets available on this web page.
RADFET Reader PRO
For measuring the output voltage of RADFET
The RADFET Reader PRO is a hand-held, battery-operated instrument designed for measuring the output voltage of Varadis RADFETs.
Built on a novel technology currently used in space applications, the RADFET Reader PRO offers the convenience and cost benefits of passive systems but with the added value of active dosimetry and the functionality of more expensive, bulkier devices.
Compatible with the following Varadis products:
The Varadis 400nm RADFET
The Varadis 100nm RADFET
The Varadis 1μm RADFET
Additional RADFET Products
In addition to the VT01 and VT02 Varadis 400nm RADFETs, we have a range of other products that we can supply on request.
These include:
- 100nm: suitable for the highest doses, up to 10 kGy and even beyond
- 1μm: suitable for lower dose range, approaching 1 mGy
Please contact us for more information on these products.
Varadis Supporting Documentation
RADFET VT01 (Datasheet)
RADFET VT02 (Datasheet)
RADFET Reader PRO (Manual)
Additional RADFETs Overview