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This document specifies methods for routine verification of the performance of acoustic emission (AE) equipment comprising one or more sensing channels. It is intended for use by operators of the equipment under laboratory conditions. Verification of the measurement characteristics is advised after purchase of equipment, in order to obtain reference data for later verifications. Verification is also advised after repair, modifications, use under extraordinary conditions, or if one suspects a malfunction. The procedures described in this document do not exclude other qualified methods, e.g. verification in the frequency domain. These procedures apply in general unless the manufacturer specifies alternative equivalent procedures. Safety aspects of equipment for use in potentially explosive zones are not considered in this document.

This part of ISO 16526 specifies a method for the direct and absolute measurement of the average high voltage of constant potential (DC) X-ray systems on the secondary side of the high voltage generator. The intention is to check the correspondence with the indicated high voltage value on the control unit of the X-ray system. This method is applied to assure a reproducible operation of X-ray systems because the voltage influences particularly the penetration of materials and the contrast of X-ray images and also the requirements concerning the radiation protection. .

This part of ISO 16526 􀀃specifies a constancy check of a X-ray system where mainly the X-ray voltage is checked and also the tube current and the constitution of the target which can be changing due to ageing of the tube.

The thick filter method is based on a measurement of the dose rate behind a defined thick filter using defined distances between the X-ray tube, the filter and the measuring device.

This method is very sensitive to changes of the voltage, but it does not provide an absolute value for the X-ray tube voltage. Therefore, a reference value is needed and, it is recommended to find this reference, for example, within the acceptance test of the system.

The thick filter method is a rather simple technique and may be applied by the operator of an X-ray system to perform regularly a constancy check of the system.

The method can also be applied for consistency checks after changing components which may affect the X-ray tube voltage.

This method can be applied for all types of X-ray systems, i. e. for constant potential, half wave and impulse wave generators with a tube current larger than 1 mA.

This part of ISO 16526 specifies the test method for a non-invasive measurement of X-ray tube voltages using the energy spectrum of X-rays (spectrometric method). It covers the voltage range from 10 kV to 500 kV. The intention is to check the correspondence of the actual voltage with the indicated value on the control panel of the X-ray unit. It is intended to measure the maximum energy only and not the complete X-ray spectrum. The procedure is applicable for tank type and constant potential X-ray units.