RAMO HENT31-021A Handheld Personal Dosimeter

Overview

The RAMO HENT31-021A Handheld Personal Dosimeter is a compact, field-deployable radiation monitoring instrument engineered for real-time measurement of ambient gamma and X-ray photon exposure in occupational and environmental settings. Unlike conventional Geiger-Müller (GM) tube–based dosimeters, this device employs a scintillation detector coupled with energy-compensated photomultiplier readout architecture—enabling enhanced detection efficiency across the 60 keV to 1.33 MeV energy range. Its operational principle relies on pulse-height analysis of scintillation light output, which is then converted into dose equivalent (µSv/h) and integrated dose (µSv to Sv) using ICRP-74 fluence-to-dose conversion coefficients. Designed for continuous wear or spot-check deployment, the HENT31-021A supports ALARA (As Low As Reasonably Achievable) compliance by delivering rapid, repeatable measurements without requiring external calibration sources during routine use.

Key Features

• Scintillation-based detection system offering >3× higher sensitivity than standard GM detectors at low dose rates (≤1 µSv/h), reducing required measurement time and operator exposure.
• Energy compensation circuitry ensures flat response across the specified photon energy spectrum—critical for accurate dose estimation in mixed-field environments (e.g., nuclear medicine departments or decommissioning sites).
• Multi-modal alert system: audible tone frequency increases linearly with dose rate; dual-color LED (green/yellow/red) and variable blink rate provide immediate visual feedback; haptic vibration triggers when user-defined threshold is exceeded.
• Ruggedized housing rated IP65—dust-tight and protected against water jets from any direction—validated for extended operation in high-humidity, outdoor, or industrial settings including nuclear power plant auxiliary buildings and radioactive waste handling facilities.
• Human-centered interface with backlit LCD display showing simultaneous real-time dose rate (µSv/h), accumulated dose (µSv/Sv), and elapsed measurement time; intuitive three-button navigation requires no training manual for basic operation.
• Low-power design powered by two standard AA alkaline cells, supporting ≥2,000 hours of intermittent use (typical duty cycle: 2 hrs/day); battery status indicator prevents unexpected shutdown during critical surveys.

Sample Compatibility & Compliance

The HENT31-021A is calibrated per ISO 4037-3:2019 (X- and gamma-reference radiations) and conforms to IEC 61526:2013 for portable radiation protection instrumentation. It meets performance criteria for personal dosimetry under national regulatory frameworks aligned with IAEA Safety Standards Series No. RS-G-1.3. While not a TLD or OSL badge replacement for formal dosimetry records, it satisfies supplementary monitoring requirements under GBZ 128–2019 (Chinese standard for occupational external radiation monitoring) and supports GLP-aligned documentation workflows where instantaneous situational awareness is required. The device does not require annual recalibration if operated within manufacturer-specified environmental limits and stored per IEC 61000-4-2 ESD guidelines.

Software & Data Management

Data export is supported via optional USB-C adapter (sold separately), enabling CSV-formatted logs of timestamped dose rate and cumulative dose values. Firmware updates are performed offline using vendor-provided utility software compatible with Windows 10/11. Audit trail functionality includes internal event logging (e.g., alarm triggers, battery swaps, self-test results) with UTC timestamps—facilitating traceability during internal QA reviews or regulatory inspections. No cloud connectivity or remote telemetry is implemented, preserving data sovereignty in secure nuclear infrastructure environments.

Applications

• Radiation safety officers conducting perimeter surveys around reactor containment structures or spent fuel pools.
• Nuclear medicine technologists verifying shielding integrity before PET/CT suite entry or after radiopharmaceutical preparation.
• Decommissioning teams performing clearance measurements on dismantled components prior to release as non-radioactive scrap.
• Environmental monitoring personnel assessing background variability near uranium mining tailings or legacy research reactor sites.
• First responders equipped with rapid-deployment kits for initial hazard characterization during radiological incident response (RDD scenarios).

FAQ

Is the HENT31-021A suitable for neutron radiation monitoring?
No. This instrument is optimized exclusively for photons (γ/X-rays) and does not incorporate neutron-sensitive converter materials or moderation geometry.
Can it be used for legal dosimetry recordkeeping?
It is not certified as a primary legal dosimeter per ISO 14146:2013; it serves as a supplementary tool for operational awareness—not statutory dose-of-record documentation.
What is the recommended calibration interval?
Annual calibration is advised under normal use conditions; more frequent verification is required after mechanical shock, exposure to extreme temperatures (>50 °C), or following any firmware update.
Does the device store historical dose data internally?
Yes—it retains up to 1,000 timestamped measurement records in non-volatile memory, accessible via USB download or on-device scrolling review.
Is the IP65 rating maintained when the battery compartment is open?
No. The IP65 seal integrity applies only when both the main housing and battery cover are fully latched and gasket-sealed per factory specification.