This part of ISO/TS 18090 is directly applicable to pulsed X-radiation with pulse duration of 0,1 ms up to 10 s. This covers the whole range used in medical diagnostics at the time of publication. Some specifications may also be applicable for much shorter pulses; one example is the air kerma of one pulse. Such a pulse may be produced, e.g. by X-ray flash units or high-intensity femtosecond-lasers. Other specifications are not applicable for much shorter pulses; one example is the time-dependent behaviour of the air kerma rate. This may not be measurable for technical reasons as no suitable instrument is available, e.g. for pulses produced by a femtosecond-laser.

This part of ISO/TS 18090 specifies the characteristics of reference pulsed radiation for calibrating and testing radiation protection dosemeters and dose rate meters with respect to their response to pulsed radiation. The radiation characteristics includes the following:
a) time-dependent behaviour of the air kerma rate of the pulse;
b) time-dependent behaviour of the X-ray tube high voltage during the pulse;
c) uniformity of the air kerma rate within a cross-sectional area of the radiation beam;
d) air kerma of one radiation pulse;
e) air kerma rate of the radiation pulse;
f) repetition frequency.