IEC 62976-2021 pdf free download – Industrial non-destructive testing equipment – Electron linear accelerator.
4.3 Operating conditions
4.3.1 Environmental requirement
• environment temperature: (5 to 40) °C;
• relative humidity: ≤90 %.
4.3.2 Power supply
• voltage: 380 V ±1 0 % three-phase four-wire AC system;
• frequency: 50 Hz ±2 % / 60 Hz ±2 %;
• power supply: it is put forward in the product manual according to the accelerator model;
• grounding resistance: special grounding resistance of modulator is less than 4 Ω.
5 Technical requirements
5.1 Appearance
The surface shall be smooth, uniform color, no obvious scratches, bumps or holes.
5.2 Control system
5.2.1 Design principle
The design of the control system shall ensure the safety of the operator, the device and the delivered dose.
5.2.2 Operation of start and stop
Operation of X-ray source start and stop shall be executed in the control console.
5.2.3 Functions of control system
The basic functions of the control system shall include:
• normal start-up and shut-down,
• display of the status of normal, fault, alarm and auto-stop,
• display of the main operational parameters,
• safety interlock,
• emergency stop.
5.3 Performance
5.3.1 X-ray beam energy
Commonly used X-ray beam energies of accelerators are shown in Table 2 and the corresponding half value layer should not be less than the value in Table 2.
5.3.2 X-ray homogeneity
X-ray homogeneity shall not be less than the value in Table 3 by using a beam flattening filter.
5.3.3 X-ray beam air kerma rate
X-ray beam air kerma rate shall achieve the value shown in Table 4 (can be reduced based on purpose).
5.3.4 X-ray beam focal spot
The diameter of the X-ray spot shall be less than or equal to 2,0 mm when the X-ray beam energy is less than 9 MeV; the diameter of X-ray spot shall be less than or equal to 3,5 mm when X-ray beam energy is equal to or higher than 9 MeV.
5.3.5 X-ray beam asymmetry
X-ray beam asymmetry shall be less than 3 % at 7,5° away from X-ray beam center axis when the X-ray beam energy is less than or equal to 9 MeV; X-ray beam asymmetry shall be less than 5 % at 6° away from X-ray beam center axis when X-ray beam energy is higher than 9 MeV. 5
.3.6 X-ray sensitivity
In the range of the X-ray beam energy and the corresponding equivalent steel thickness stated in Table 5, X-ray sensitivity shall be less than 1 % as determined by linear densitometry for imaging detection.
5.3.7Dose leakagea) X-ray dose leakage
measure of leakage is given by the ratio of X-ray dose rate 1 m away from the target ina variety of directions to the X-ray dose rate on the central beam axis. This shall beexpressed as a percentage and shall be less than 0,1 %.
b) Neutron dose leakage (if the accelerator energy is higher than or equal to 10 Mev)
Neutron dose rate shall be no more than 0,01 mSv/h 1 m away from the target beyond thex-ray field formed by the forward collimator and no more than 0,001 mSw/h in other places.5.4 Electrical safety
5.4.1Protective grounding
Separated electric shock protection is essential. The resistance between metal surface andgrounding terminal shall not be more than 0,1 Q.
5.4.2Insulation resistance
The insulation resistance between wires (including phase line and zero line) and ground ofeach independent electrical part of the equipment should not be less than 1 MQ when the testvoltage (AC RMS or DC aweragey reaches to 1 000 v.
5.4.3Dielectric strength
Electrical equipment with electrical grounding should tolerate the dielectric strength testing of2 000 v(AC RMS or DC average) with no breakdown and no repeated arcing during the test.
5.4.4Protection against electric shock
Electrical equipment of the accelerator should have anti shock functionality under thecondition of normal use,the touchable parts should not be hazardous or live. The voltagebetween accessible component and ground terminal should be less than AC 30 v or Dc 60 v,The warning symbols for“high voltage”shall be posted near the high voltage device.
5.5 Reliability
5.5.1Continuous operation
The device shall be able to operate for 8 h with less than 4 interruptions lasting no more than3o min each.
5.5.2Recovery
The time of reaching the normal work status shall be less than 15 min when the downtimewithout fault is longer than 1 h after shutdown.
5.5.3Restart
The time of reaching the normal work status shall be less than 150 min when the downtimewithout fault is longer than 48 h after shutdown.IEC 62976 pdf download.