The Measall KC761A is a portable radiation multimeter and spectrometer designed to provide considerably more information than a conventional Geiger counter.

At its core is a 2.54cm³ CsI(Tl) scintillation detector coupled to a SiPM sensor and integrated multi-channel analyser. By measuring both the energy and intensity of detected radiation, the KC761A can display radiation spectra, identify characteristic energy peaks and provide energy-compensated dose measurements.

With an energy response from approximately 9keV to 3MeV, high gamma sensitivity and spectral resolution of up to 8.2% FWHM at 662keV, it is particularly well suited to gamma and X-ray measurement, isotope investigation and field radiation monitoring.

High-Resolution Radiation Spectrometer

Unlike a basic counter that primarily reports the number of detected events, the KC761A incorporates a multi-channel analyser to measure the energy distribution of incoming radiation.

This allows the instrument to display a full spectrum and examine characteristic energy peaks from different radiation sources. The CsI(Tl) scintillator and low-noise SiPM front end provide a typical spectral resolution of up to 8.2% FWHM at 662keV.

Spectrum Mode

Spectrum Mode displays the measured radiation energy spectrum, allowing individual peaks and spectral characteristics to be examined directly on the instrument.

Measurement data can also be saved for later analysis, making the KC761A useful for experimental work, source comparison, educational applications and more detailed radiation investigation.

Energy-Compensated Dose Measurement

In Dose Mode, the KC761A displays radiation dose rate together with a time-based graph showing how radiation levels change during the measurement.

Rather than relying solely on pulse count, the instrument measures pulse energy and applies compensation for the detector's differing sensitivity across the energy range. This allows more representative dose and dose-equivalent measurements than a simple uncompensated count-rate display.

Cumulative dose can also be recorded, giving the operator additional information during longer measurements.

Secondary PIN Detector

In addition to the main scintillation detector, the KC761A incorporates a 16mm² PIN detector.

The PIN detector is housed to minimise electrical and optical interference and is covered by a Mylar film. It can be used for experimental measurements involving alpha and beta radiation.

An additional internal sensor position also provides provision for optional sensor modules, such as a neutron detector.

Temperature-Compensated Measurements

The KC761A incorporates active temperature compensation within the scintillation probe. The instrument has been characterised across a wide temperature range, helping reduce measurement drift as ambient conditions change.

This is especially useful during long spectrum accumulation periods where changes in temperature could otherwise shift measured energy peaks.

USB-C, Ethernet, PoE and Data Storage

Multiple interfaces provide extensive options for standalone, portable and permanently networked use.

Pulse signals from the detector can also be output through the 3.5mm connection for use with external analysis equipment.

Save and Export Measurement Data

A dedicated Save function allows measurement results and screen captures to be stored to a compatible TF card, sold separately.

Supported stored information includes:

• Screen captures in BMP format
• Dose-rate data
• Spectrum data
• Multi-channel analyser raw data in CSV format

Saved spectrum files can be transferred for further analysis using compatible software, including open-source spectrum analysis applications such as InterSpec.

Android, iOS and Network Connectivity

The KC761A can connect to compatible Android and iOS devices using the KCSDI app, allowing remote operation and measurement data export.

Ethernet connectivity also allows network-based monitoring and viewing from a computer, while Power over Ethernet simplifies permanent installations where multiple instruments are used as part of a monitoring network.

AA Battery Power for Long-Term Readiness

The KC761A uses readily available AA batteries and is designed for approximately 300 hours of battery operation, making it suitable for portable field use and long-term emergency storage.

Compatible rechargeable NiMH batteries can also be charged by the instrument.

Rugged Field Design

The KC761A is built for portable use with a rugged, flame-retardant enclosure designed for exploration, scientific fieldwork, monitoring and emergency applications.

It carries an IP65 rating, provides approximately 1.5m drop protection and is designed for operation from -10°C to +50°C.

Audible, visual and vibration alerts can be used to warn the operator when radiation levels exceed the configured threshold.

Technical Specifications