GB 7667-1996 Electron microscope X-ray leakage dose

This standard specifies the X-ray leakage dose, test methods and inspection rules for electron microscopes (hereinafter referred to as electron microscopes). This standard applies to different types of electron microscopes such as transmission, scanning, reflection, transmission scanning and electron probes. GB 7667-1996 X-ray leakage dose of electron microscope GB7667-1996 Standard download and decompression password: www.bzxz.net

National Standard of the People's Republic of China
The dose of X-rays leakage from electron microscope1The subject content and scope of application
GB 7667--1996||tt| |Replaces GB7667--87
This standard specifies the X-ray leakage dose, test methods and inspection regulations for electron microscopes (hereinafter referred to as electron microscopes). This standard applies to different types of electron microscopes such as transmission, scanning, reflection, transmission scanning and electron probes. 2 Technical requirements
The air absorbed dose rate of X-ray leakage from the electron microscope should not be greater than 2.5 μGy/h. 3 Test methods
3.1 Test equipment
X-ray dose rate meter with correction factor (referring to corrected X-rays), its level is Level 2. The minimum scale value cannot be greater than 1μGy/h. 3.2 Test steps
3.2.1 Adjust the accelerating voltage to the highest level, and select the maximum normal operating beam current and maximum beam spot. 3.2.2 Adjust the condenser to normal working condition, adjust the magnification to the lowest level, and exit all movable apertures. For scanning electron microscopy and electron probe measurements, tungsten should be used as the sample and the absorption current should be adjusted to the maximum value. 3.2.3 The test parts are the photographic room, observation room, sample room, movable aperture, electron gun (the tested part of the electron gun when the electron microscope acceleration voltage is equal to or greater than 400kV refers to the isolation layer), vacuum pipeline, picture tube, lens barrel and its ancillary devices. When testing a location above the sample chamber, the movable aperture of the objective lens should be inserted into the electron beam channel.
3.2.4 Move the X-ray dose rate meter slowly 50mm away from the test site to measure the X-rays. Air absorbent base rate for maximum leakage.
4 Inspection Rules
The product inspection sampling plan is carried out according to the unit-by-unit inspection plan. Additional notes:
This standard is proposed by the Ministry of Machinery Industry of the People's Republic of China. This standard is drafted and managed by Shanghai Institute of Electronics and Optics Technology. Approved by the State Bureau of Technical Supervision on 1996-08-13 634Www.bzxZ.net
implemented on 1996-12-01
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