BHC336 Scaler for Radioactivity Measurement

Overview

The BHC336 Scaler is a high-stability, multi-purpose radiation measurement instrument engineered for precise pulse counting and spectral analysis in low- to medium-count-rate applications. Based on single-channel pulse-height analysis (SCA) architecture, it operates as a digital scaler-timer with integrated discriminator functionality—enabling discrimination, windowing, and integration modes for gamma, alpha, beta, neutron, and radon/thoron detection. Its core measurement principle relies on pulse amplitude discrimination of detector output signals, allowing selective counting within user-defined energy windows. Designed for laboratory, environmental monitoring, and industrial radiometric applications, the BHC336 supports interchangeable detector interfaces—including NaI(Tl) scintillators, Geiger-Müller tubes, proportional counters, ZnS(Ag) alpha detectors, plastic scintillators for beta, Li-glass/³He/BF₃ neutron detectors, and FD125-type radon chambers. The system integrates an ARM9-based embedded controller, high-resolution color TFT touchscreen, and dual-polarity programmable HV/LV power supplies—eliminating the need for external bias sources across most standard radiation detectors.

Key Features

• Single-channel analyzer (SCA) with three operational modes: differential (peak search), narrow-window (energy-selective counting), and wide-window (integrated spectrum counting)
• Dual-mode counting: preset time (timer) or preset count (scaler) acquisition protocols with automatic termination and data freeze
• Programmable high-voltage supply (–1000 V to +1000 V, 0.1 V resolution) and low-voltage outputs (±12 V, ±5 V) for direct probe powering
• Real-time plateau curve acquisition: automated HV stepping, count-rate logging, and graphical display for optimal operating voltage determination
• Maximum input count rate: 5 MHz with <100 ns dead-time correction capability and pulse-pair resolution
• Embedded ARM9 processor with 64 MB RAM and 128 MB flash storage for onboard data logging (up to 10,000 spectra or timed runs)
• 7-inch resistive touchscreen (800 × 480 pixels) with intuitive GUI supporting Chinese/English language switching
• Multi-interface connectivity: RS-232 serial port, USB 2.0 host/device, and 10/100 Mbps Ethernet for remote control, firmware updates, and real-time data streaming

Sample Compatibility & Compliance

The BHC336 is compatible with industry-standard radiation detectors requiring analog pulse output and bipolar HV bias. It meets electromagnetic compatibility (EMC) requirements per GB/T 18268.1–2010 (equivalent to IEC 61326-1) for laboratory equipment used in radiological measurement environments. Its thermal design ensures stable operation under ambient conditions of 0–40 °C and ≤90% RH (at 30 °C), conforming to IEC 60068-2 environmental testing standards. While not certified for clinical use under ISO 13485 or FDA 21 CFR Part 11, its data export protocols (CSV, TXT, binary) support traceable recordkeeping in GLP-compliant laboratories. The instrument adheres to national metrological verification regulations JJG 859–2019 (Calibration Specification for Radiation Scalers) for accuracy validation in China’s regulatory framework.

Software & Data Management

The embedded firmware supports local parameter configuration—including acquisition duration, count threshold, SCA window settings, HV ramp parameters, and auto-save intervals—without PC dependency. All configurations and raw count data are stored internally with timestamping and session ID tagging. Via the included Windows-compatible PC software (BHC-Control Suite v3.x), users can perform advanced post-processing: spectral deconvolution, efficiency calibration using reference sources (e.g., ¹³⁷Cs, ⁶⁰Co), background subtraction, and dose rate conversion using detector-specific response factors. Data exports include ASCII-delimited files suitable for import into MATLAB, OriginLab, or Excel; binary archives retain full pulse-height histogram metadata. Audit trails—comprising operator ID, timestamp, HV setting, and acquisition mode—are recorded per session and exportable for QA documentation.

Applications

• Nuclear physics education and research: gamma spectroscopy fundamentals, half-life measurements, coincidence timing studies
• Environmental radioactivity monitoring: soil/water radon (²²²Rn) and thoron (²²⁰Rn) concentration via FD125-type diffusion chambers
• Industrial NDT: thickness gauging using beta transmission, surface contamination screening with GM probes
• Agricultural radioisotope tracing: ³²P or ¹⁴C uptake kinetics in plant tissues
• Medical physics QA: constancy checks of brachytherapy source strength and survey meter linearity verification
• Regulatory compliance: routine performance testing of radiation protection instrumentation per CNIC guidelines

FAQ

Does the BHC336 support energy calibration with standard gamma sources?
Yes—it accepts manual or semi-automated energy calibration using two-point (e.g., ⁶⁰Co at 1173 keV and 1332 keV) or multi-point methods via the SCA window adjustment interface.

Can it operate standalone without a PC connection?
Yes—all core functions—including timer/scaler acquisition, plateau analysis, and data storage—are fully operational without external computing devices.

What is the minimum detectable activity (MDA) for radon using FD125?
MDA depends on chamber volume, airflow, and counting time; typical values range from 2–5 Bq/m³ for 60-min integrations under lab conditions.

Is firmware upgrade possible in the field?
Yes—via USB flash drive or Ethernet; version history and release notes are provided with each update package.

Does it meet CE or RoHS requirements?
The unit complies with China’s CCC certification requirements; CE marking is not applicable as it is domestically manufactured and distributed under PRC regulatory scope.