Low-frequency magnetic shielding room for cathode luminescence systems, scanning electron microscopes, transmission electron microscopes, material analysis equipment, and other precision instruments.

Basic Requirements

The laboratory will be composed of a gas cylinder room, a changing room, a wind shower room, and a clean room, all outside the laboratory space. Upon completion, the laboratory will meet the installation conditions specified by the instrument manufacturers.

The site laboratory report indicates that the DC magnetic field exceeds the standard, necessitating the implementation of a passive magnetic shielding system.

Engineering design fundamentals include: 1) Rational structure, with materials selected for energy conservation, environmental protection, flame retardancy, and rust prevention; 2) Adhere to the people-oriented principle, ensuring the overall aesthetics of the laboratory; 3) Stable and reliable system, easy for daily maintenance and repair.

Completion of laboratory construction required

1. Ensure the AC magnetic field inside the electron microscope room: Frequency between 10 Hz to 1 kHz, <1mG (peak-to-peak), DC magnetic field: Change less than 0.5mG within 5 minutes, and fully consider the impact of subsequent magnetic field changes.
2. 2. Ensure electron microscope room noise: 20-120Hz: <52dB, 120-450Hz: <43dB, above 450Hz: <47dB
3. 3. Ensure indoor vibration: Vibration in the horizontal direction with frequencies between 0-10Hz, vibration rate < 7 um/sec; frequencies between 10-60Hz, vibration rate < 15 um/sec; frequencies above 60Hz, vibration rate < 20 um/sec.
4. Vertical vibration with frequencies ranging from 0-10 Hz, vibration rate < 6 um/sec; frequencies between 10-60 Hz, vibration rate < 20 um/sec; frequencies above 60 Hz, vibration rate < 30 um/sec.
5. 4. The ground under the electron microscope's main unit should not be paved with steel plate, and it should be sturdy and durable, easy to maintain.
6. 5. Detailed descriptions of the key technologies for laboratory magnetic field shielding control are required.
7. 6. Supply exhaust ventilation and air conditioning systems that meet the indoor constant temperature requirements (environmental temperature: 21°C +/- 4°C, stability: 0.5°C/h), low noise, and long-lasting durability.
8. 7. The laboratory door width and height should accommodate the entry of equipment.
9. 8. The power supply for the electron microscope main unit should be 220V, single-phase three-wire, without leakage protection, and a 25A current with an independent switch.
10. Magnetic shielding decorative section:
11. The main shielding shell is constructed using a high permeability material welding structure to form a hexahedral magnetic shielding shell.
12. 2. The low-carbon shielding steel plate (magnetized treated) requires continuous full welding, and the structural shell needs to be double-sided welded.
13. 3. Ribs: Welded with square steel for support; beams are reinforced with square steel welding.
14. 4. Welding Method: Full seam welding is used between the panels.
15. 5. The structure is assembled on-site. Based on the site conditions and technical requirements of the drawings, assembly and hoisting plans are formulated to ensure engineering and technical quality.
16. 6. After the steel plate is processed and trimmed, it must undergo a special anti-magnetic treatment before it can be transported to the construction site.
17. Vibration Resistance Section:
18. 1. Method of vibration isolation for waveguide mounts. Active damping equipment as a backup solution.
19. 2. The quality of the concrete vibration-reducing foundation is determined by the specific foundation conditions. The concrete vibration-reducing pad should be connected to the outside world through a "soft connection."