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The Radiological Detection System (RDS) Field Instrument for the Detection of Low Energy Radiation (FIDLER) Probe is used for low-energy X-ray and gamma radiation detection. The FIDLER Probe detects and distinguishes between low-energy X-rays and gammas. It simultaneously records data over four separate energy windows, by use of a multichannel discriminator. Analysis of this information can enable the detection of materials commonly used in weapons of mass destruction. The FIDLER Probe monitors all four of the following energy windows simultaneously. The Base Unit Home screen has the ability to display one or two energy channels at a time.

• Energy Window 1: 13 – 18 keV

• Energy Window 2: 59 – 60 keV

• Energy Window 3: 143 – 220 keV

• Energy Window 4: 13 – 220 keV 

FIDLER Probe Features:

  • Large gamma NaI(Tl) scintillator

  • Part of the RDS radiation detecting probe family

  • Adjustable handle 

  • Multi-channel discrimination

  • Simultaneous detection of 4 channels + display of 2 selectable channels

  • Works with Rad-Extender to download data

  • Common probe connector cable can be used with any Rad Defender probe

  • Durable, easy-to-use ergonomic design with optional shoulder strap

  • Robust cable connections

  • Smart Probe functionality stores calibration on probe - can be used with any Base Unit

  • Designed and tested for military ruggedness to meet both military/defense requirements and industrial applications


As a smart probe, the FIDLER Probe contains a microprocessor and high voltage circuitry for creating its own high voltage. No high voltage is transferred across the interface cable. When connected to the Base Unit, the display will show the probe’s image and radiation measurement—the probe’s onboard memory stores the probe type and calibration information.


RDS Products

RDS Base Unit

Powerful and easy-to-use radiation detection. Powers and displays the full suite of RDS probes

Beta Photon Probe

Expanded capability for detecting high energy photons and beta radiation

Neutron Probe

Solid state neutron detection from 0.025 eV to 15 MeV

Alpha Beta Probe

Detect alpha and beta surface contamination

Sensitive Gamma Probe

Detect low levels of gamma radiation across a broad range of energies

RDS Accessories

Expand the RDS capabilities with a broad range of rugged equipment options

Alpha Beta Gamma Pancake Probe

Small and lightweight probe for detecting alpha, beta, and gamma contamination


Simultaneously detect low-energy x-ray and gamma radiation over four energy windows

Manual Icon

Learn more about the RDS operation and specifications

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