May 8, 2024

Pulsed radiation dose measurement added to the GMS595


In a groundbreaking collaboration between AWE (The Atomic Weapons Establishment) and JCS Nuclear Solutions, the GMS595 has emerged as a game-changer in the field of gamma monitoring.

Unlike conventional gas-filled detectors, which require warm-up time and are affected by temperature and pressure, the GMS595 operates seamlessly without delays. From nano Sieverts per hour (nSv/hr) to 1 Sievert per hour (Sv/hr), this instrument provides accurate measurements across a wide gamma dose-rate range and an impressive energy response from 32 keV to 7 MeV.

Today, JCS are happy to announce the first in a suite of upgrades to the GMS595: the ability to measure pulsed fields.

Pulsed Gamma and X-ray Fields

The latest development in the GMS595’s capabilities is its ability to measure dose rates in pulsed gamma and x-ray fields.

This breakthrough extends its applications beyond traditional gamma monitoring. Now, radiation protection professionals can confidently use the GMS595 for non-destructive testing (NDT) and shielding surveys, even in high-powered betatron and x-ray generator environments.

Continuous Pulsed Radiation

Continuous pulsed radiation refers to a mode of radiation exposure where short pulses of radiation are used instead of continuous exposure. Unlike continuous (uninterrupted) radiation, which maintains a constant intensity, pulsed radiation involves periodic bursts or pulses of radiation.

Pulse Frequency and Dose Reduction

In contrast to continuous fluoroscopy, which provides a continuous stream of X-rays, pulsed fluoroscopy aims to reduce the dose to patients and staff by using short pulses of radiation. The pulse frequency should be as low as possible while still achieving clinically desired results. Short pulses minimise the overall radiation exposure, leading to reduced dose accumulation over time.


  • Frequency: 200 Hz
  • Pulse Width: 1 µs (microsecond)
  • Betatrons are commonly used for high-energy electron beam therapy in cancer treatment.


  • Frequency: 360 Hz
  • LINACs accelerate charged particles (usually electrons) along a linear path.
  • They are used for various medical procedures, including radiation therapy for cancer treatment.
  • So far, only very low dose rates have been tested with LINACs, further testing is planned for later this year.

X-Ray Generators

  • These devices are portable X-ray generators used for NDT and security applications.
  • Frequency: 10 Hz
  • Pulse Width: 10 ns (nanoseconds)
  • Maximum Energy (Emax): 250 keV (kilo-electronvolts)
  • The short pulse width allows for precise imaging while minimising radiation exposure.


The GMS595 finds relevance in various sectors:

  • Nuclear power generation: ensuring safety during reactor operations and maintenance.
  • Nuclear fuel processing: monitoring radiation levels in fuel processing facilities.
  • Non-destructive testing (NDT): assessing material integrity without damaging the structure.
  • Fusion energy research: supporting experiments in controlled nuclear fusion.
  • Nuclear decommissioning: safeguarding workers during decommissioning activities.
  • Defence and security: detecting radiation threats in critical areas.
  • Medical physics and nuclear medicine: precise dose-rate measurements in medical settings.

Visit the GMS595 web page here >>>

Firmware Updates

The GMS595 has undergone several firmware updates, enhancing its functionality and compatibility:


First production release firmware providing the following:

  • Primary operational requirements achieved
  • Laid the foundation for subsequent improvements.


The first major firmware update brings the following improvements:

  • Integrated dose feature, allowing operators to select functionality between standard dose-rate measurements and setting up total dose interval parameters for integrated dose measurements.
  • ntroduces a new boot-loader functionality, giving calibrators and admins the ability to upgrade new instrument firmware. Removing the requirement to return the instrument to the JCS Nuclear Solutions for firmware upgrades.


Pulsed-field measurement capability comes to the GMS595 for non-destructive testing and shielding survey applications  This update brings the first wave of pulsed-field measurement capability after extensive testing with Betatron generators:

  • Betatron compatible.
  • Updated hardware support.


This update is all about laying the foundation for exciting hardware upgrades, including a new beta detector. This firmware will allow efficient manufacture, set up, test and calibration of each GMS595 model variant:

  • Support was added for beta detector measurements.
  • Automatic detector recognition streamlines manufacturing and setup operations.
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