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
Six Lead SOT-23 Plastic Package
400nm doses between 10 cGy (10 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 4 volts).
Varadis RADFET VT02
Eight Lead Ceramic Side Braze Package
400nm doses between 10 cGy (10 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 4 volts).
Important Information: The VT01 & VT02 RADFET has a large dynamic range, capable of 1 cGy (1 rad) to 1 kGy (100 krad). 1 cGy can be achieved with ideal temperature compensation and high-precision I-V measurement instrumentation (e.g. high-quality bench-top equipment) for RADFET read-outs.
Please note the VT01 and VT02 will operate comfortably from 10cGy outside of the above conditions.
VT01 and VT02 products can also measure doses even higher than 1 kGy. They come calibrated up to 1 kGy but additional calibration can be applied for measurements beyond this limit. Please contact support@varadis.com for further details.
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 V01 and V02 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
The exact dose ranges will depend on the customer’s application requirements and the design of readout circuitry.
Please contact us for more information on these products.
Varadis Supporting Documentation
RADFET VT01 (Datasheet)
RADFET VT02 (Datasheet)
RADFET Reader PRO (Manual)
Varadis Price Guide
Additional RADFETs Overview