tokens: The energy deposition spectrum by direct ionisation shall be calculated by one of the following methods : 1 . By using the formula of Clause 10.4.9.1 , if both of the following conditions are met : ( a ) the sensitive volume of the sensor is so small that the incident particle spectrum changes by less than 10 % in either intensity or energy after passing through the volume ; ( b ) the pathlength distribution changes by less than 10 % as a result of multiple scattering . 2 . By a radiation transport simulation agreed with the customer . NOTE For guidelines , see ECSS - E - HB-10 - 12 Section 5.7 .