How to select a right linear electron accelerator for your electron beam irradiation plant? It’s a big problem for a beginner or new player in industrial irradiation sterilization business. Here to introduce some key factors to help you select right electron beam irradiation equipment and electron beam irradiator.
1. Basic Components of Linear Electron Accelerator Irradiation Devices
1.1 Main System
Accelerates electrons emitted by the electron gun to near the speed of light. The electron beam is output through a titanium window and scans objects. As the object moves forward at a uniform speed, it receives uniform irradiation, and the required irradiation dose is achieved based on the amount of energy absorbed by the electron beam.
1.2 Microwave Power Source
The microwave power source outputs 5000 kW of microwave pulse power (equivalent to the power output of 6000 household microwave ovens) to drive electron acceleration. This system is extremely complex and critical to the performance, efficiency, safety, and reliability of the entire equipment set.
1.3 Control System
Coordinates the operation of each equipment system and provides emergency protection. Typical irradiation accelerator control systems use highly reliable programmable logic circuits (PLC) for industrial control. These systems offer basic on/off logic and interlock protection but have limited functionality and slow speeds.
High-end irradiation accelerators adopt FPGA-based intelligent computer control systems, integrating high-speed data sampling, database storage, remote control, and rapid protection features. This setup facilitates refined analysis of system operation, long-term data storage and retrieval, and fault analysis.
2. Key Technical Specifications of the linear electron accelerator
2.1 Output Beam Current
The quantity of electrons emitted from the titanium window per unit of time, also known as the electron beam current. It uses the same unit as electric current, measured in amperes (A) or milliamperes (mA).
2.2 Output Energy
The kinetic energy of the electron beam emitted from the titanium window, measured in electron volts (eV) or mega-electron volts (MeV). The standard output energy of irradiation linear accelerators is 10 MeV.
2.3 Output Power
Calculated as:
Output beam current (A) × Output energy (eV) = Output beam power (W)
During operation, the output power (W) is determined by measuring the beam current (A) while the electron beam energy reaches its nominal value. It is crucial to avoid separately measuring energy and beam current under different conditions, as this could lead to an overestimated calculated power. Currently, many electron linear accelerators with a nominal power exceeding 30 kW fail to achieve their rated power in practice.
2.4 Energy Conversion Efficiency
Calculated as:
Output beam power / Input electrical power = Energy conversion efficiency
Electrical power from the grid is converted to high-voltage pulse power, then to microwave power, and finally to electron beam power. Factoring in these efficiency losses and auxiliary power consumption, the energy conversion efficiency of electron linear accelerators is about 8–18%. An accelerator producing 20 kW of beam power consumes 250 ~ 111 kW of electrical power. The system design of irradiation accelerators significantly affects energy efficiency.
3. Analysis of Linear Electron Accelerator Production Capacity
3.1 Definition of Object Absorbed Dose
One joule of energy absorbed by one kilogram of material represents one dose unit, Gy (Gray). When 1000 joules of energy are absorbed by one kilogram of material, the dose is 1 kGy.
3.2 Output Energy of Irradiation Accelerators
An accelerator with 20 kW beam power outputs 20 kJ of radiation energy per second or 72,000 kJ per hour.
3.3 Irradiation Capacity
For products requiring an irradiation dose of 8 kGy, using a 20 kW accelerator, assuming all radiation energy is absorbed uniformly, 72,000 kJ ÷ 8 kJ = 9,000 kg of goods can be irradiated per hour. If the radiation utilization efficiency is 70%, the hourly throughput is approximately 6.3 tons. If actual throughput is significantly lower than the calculated value, it may indicate either the actual beam power is much lower than the nominal value or system design issues causing low beam utilization efficiency.
4. Analysis of Linear Electron Accelerator Operating Costs
4.1 Operating Costs
The main costs include electricity, labor, financial expenses, and depreciation (excluding maintenance costs, which are calculated separately). Electricity costs dominate. Inefficient accelerators operating at full power consume 250 kWh, typical ones consume 180 kWh, fully solid-state ones consume 135 kWh, and the most advanced ones consume 110 kWh. Assuming 6,000 hours of operation annually, electricity consumption could exceed 500,000 kWh, with substantial cost differences.
4.2 Maintenance Costs
The key consumables are electron guns, klystrons, and thyratrons, with supplier-guaranteed lifespans of approximately 2000h, 5000h, and 4000h, respectively. Actual lifespans are around 4000h, 10,000h, and 8000h. High-end accelerators can achieve lifespans exceeding 30,000h, 20,000h, or even unlimited lifespans. Comprehensive maintenance packages (including labor and consumables) cost around USD 600,000.00 annually, while labor-only maintenance costs USD 400,000. Long-term average maintenance costs can vary significantly across different suppliers.
5. Existing Issues with Linear Electron Accelerator Irradiation Devices
5.1 Limited Industrial Application History and Maturity
The use of electron linear accelerators in irradiation processing is relatively recent. The technology is still maturing and undergoing research to improve its reliability. While high irradiation efficiency promotes rapid adoption, applications in fields like medical product irradiation involve certain risks. Continuous technological advancement is key to ensuring safe and efficient usage.
5.2 Misalignment Between Technical Indicators and Application Needs
Some technical indicators do not directly relate to irradiation applications, and promotional claims may mislead even professionals. A deeper understanding of equipment performance and irradiation applications is necessary.
5.3 Harsh Operating Environment
Irradiation accelerators operate under high voltage, strong electric fields, and intense radiation. Without long-term application testing and improvement, it is challenging for equipment to achieve stable, long-term operation.
6. Importance of Intelligent Linear Electron Accelerator
6.1 Reaction Time of Control Commands
The pulse width of irradiation accelerators ranges from 4–16 microseconds. Traditional PLC control systems, with instruction cycles of around 2 milliseconds, cannot respond rapidly to pulses, limiting their control capabilities. High-end equipment achieves microsecond-level response times, ensuring precise and stable operation.
6.2 Importance of Data Storage and Computation
Large vacuum electronic components in accelerators experience gradual parameter changes over time. Data storage and computation over periods exceeding six months are essential for assessing electrical parameters and expected lifespans. Similar monitoring is required for other components.
6.3 Data Transmission and Remote Monitoring
Data sharing and remote monitoring via networks are crucial for analyzing equipment operation, diagnosing faults, and resolving issues.
7. Construction of Radiation Protection Facilities
7.1 Construction of Radiation Protection Facilities
Radiation protection facilities are designed based on supplier specifications and must be approved by local nuclear agencies. Construction costs can vary significantly depending on the design and implementation.
7.2 Ownership Division in Construction
Due to technical and communication challenges, integrating protection facilities into factory buildings can be difficult, leading to increased investment costs. Constructing these facilities as part of equipment systems within completed buildings can simplify processes and significantly reduce costs.
7.3 Quality Control in Construction
Radiation protection facilities differ from general building construction. Any quality control errors can prevent rework or corrections. Communication and coordination between design, construction, supervision, and acceptance teams are particularly important.
8. Comprehensive Evaluation Considerations
8.1 Investment Costs
The equipment investment cost for a new linear accelerator system may not vary much based on market conditions, but site construction costs can lead to significant differences in overall investment.
8.2 Production Efficiency Considerations
Operational efficiency greatly influences the return on investment. In-depth understanding of equipment performance and analysis of operational parameters are essential.
8.3 Operating Cost Considerations
Factors such as energy consumption, consumables, maintenance costs, and fault rates can cause significant differences in operating costs, which cannot be overlooked.
Conclusion
The linear electron accelerator is key component in the electron beam irradiation equipment. If you can not select a right accelerator, it will affect your business profit. EBM MACHINE provide you a high throughput, low electrical power consumption, cost-effective and low maintenance cost electron beam irradiation equipment for your industrial sterilization business.