Product Introduction

The CIT-3800 Low Background High Purity Germanium Gamma Spectrometer is composed of high purity germanium detectors, a low-temperature恒温器, a shielding lead chamber, a digital energy spectrometer, and a multi-functional spectrum analysis software. It is widely applicable in measuring the types and levels of radioactive nuclides in various environmental samples, reactor effluents, post-processing samples, radioactive pharmaceuticals, and low-activity lake sediment samples.

The product is applicable in fields such as nuclear power, environmental testing, inspection and quarantine, archaeology, material analysis, nuclear structural analysis in nuclear physics, molecular physics research, atomic collision research, chemistry, geometallurgy, and more.

Technical Specifications

Work Conditions

• Power: 220V ~ 240V, 50Hz

• Temperature: -10~55℃

• Humidity: ≤ 85% (no condensation).

Relevant Standards

• Meets the current national standards, such as GB/T 16145-2022 "Method for Analyzing Gamma Energy Spectrum of Radioactive Nuclides in Environmental and Biological Samples."

High-purity Germanium Detector

• Adaptable to various specifications and models of HPGe detectors according to customer requirements; for example, a P-type coaxial wide-energy detector with a 50% efficiency:

• Energy Range: 3 keV ~ 10 MeV

• Relative Detection Efficiency: ≥50%

• Energy Resolution (FWHM): ≤0.87 KeV for the 122 keV peak (Co-57)

• For the 1.33 MeV peak (Co-60): ≤1.9 keV

• Peak 康比：≥ 64:1

• Peak Parameters: FW0.1M/FWHM ≤2.0; FW0.02M/FWHM ≤3.00.

Digital Multi-Analyzer

• Data Throughput: Greater than 100 kcps

• Coarse Gain: Options available are 1, 2, 4, 8, 16, or 32.

• Fine-tune Gain: adjustable from 10,000 to 60,000 levels

• Address: 8K/16K/32K adjustable

• Forming Time Constant: Rise time adjustable from 0.05μs to 50μs in steps of 0.05μs; flat-top time from 0 to 32μs in steps of 0.05μs, selected by the *computer (automatically adjusted under the automatic optimization feature).

• Linear: Integral non-linearity ≤ ±0.025%; Differential non-linearity ≤ ±1%.

• Output Stability: Long-term Drift: ≤0.01%/h; ≤0.02%/8h

• Temperature Coefficient: Gain < 35 ppm/°C; Zero Point < 3 ppm/°C

• Signal Processing: Features digital spectrum stabilization, automatic pole-zero identification, digital gate-controlled baseline recovery, and low-frequency noise suppression.

• Dead-time correction: (with peak area change) <3% (0~50,000 cps)

• High Voltage Module: adjustable from 0~5kV, output current 0-100uA.

• Communication Interface: Network interface, with good compatibility.

• Operating Temperature: -10~50°C.

Energy Spectrum Analysis Software

• Features include spectrometer control, energy scaling, peak hunting, spectrum analysis, isotope library search, data management, and automatic generation of analytical reports.

• The spectrometer parameter adjustments include: fine gain adjustment, initiating digital stabilization, adjusting high voltage, displaying dead/living time, setting up/down discrimination thresholds, etc.

• Energy Scale: Peak positioning via single-peak fitting, real-time nucleotide peak information query feature.

• Seek Peak: Utilize first and second derivative methods to locate isolated peaks, and based on peak shape fitting, conduct a secondary peak search to determine the position of double peaks.

• Efficiency Scale: Utilizes the efficiency scale curve obtained from experimental measurements, featuring built-in cascade and cumulative efficiency scale factor correction calculations.

• Peak Fitting: Subtracts the background through peak fitting to resolve overlapping peaks, obtaining a net counting rate. Features a non-linear background subtraction method and automatically adjusts to the trend of energy spectrum changes. Utilizes Gaussian functions or a combination of Gaussian and exponential functions for tail fitting, demonstrating excellent fitting capability for distorted peak shapes.

• Activity Calculation: For different γ peaks of the same nuclide, the activity is calculated through weighted average, taking into account branching ratios and efficiency scale factors. During the activity calculation, consider the nuclide decay during the measurement process and dead-time correction, etc.

• Small detectable limit calculation

• Uncertainty Analysis: Calculates the uncertainty in energy spectrum measurements by integrating the uncertainty of detection efficiency and counting rate.

• Analytical Nuclide Library: Comprises over 200 radioactive isotope spectral lines, allowing users to customize and add as needed during use, with real-time querying of spectral line information.

• Features full-automatic quantitative analysis, allowing users to customize the format of measurement result reports.

• Built-in passive efficiency scale function; input characteristic scale files and correction files; editable container density, volume, material, and other element information to obtain sample efficiency curves.

Lead Shielding Room

• Shell: 10mm low-carbon steel

• Primary Shielding Body Lead Thickness: ≥ 10 cm

• Segmented Lining: 2mm Low Background Tin and 2mm Low Background Copper

• Lead room interior dimensions: ≥ 28cm diameter × 40cm height

• Base Points: ≤2cps (50% efficiency detector, 40keV~2000keV).

Electro-cooled Liquid Nitrogen Recompression Unit

• Compressor lifespan exceeds 180,000 hours.

• Continuous refrigeration for the detector for over 18 months without power interruption.

• Fueled with liquid nitrogen, the system ensures continuous operation for over 7 days without power.

• LCD display, capable of showing parameters such as power, pressure, liquid level, and temperature.

• Equipped with two safety pressure relief valves, ensuring the equipment itself does not pose an overpressure risk due to power failure, and also preventing the failure of a single hydraulic valve.

Configuration List

• 1 set of high-purity germanium detectors

• 1 digital multi-channel analyzer

• 1 unit of electric refrigeration liquid nitrogen condensation unit

• 1 set of low-background lead room

• Spectrum analysis software 1 set

• 1 set of computers and printers

• Optional electric refrigerated detectors, calibration sources, Dewar flasks, UPS power supplies, and Marin cups, etc., as low-value consumables.