Abstract: The contribution from the geometrical factors to the radiation nonuniformity in the case of an open-end cylindrical hohlraum is discussed. The analysis is facilitated by using temperature profile of the cylindrical hohlraum heated by the two ring sources, the temperature profile of a Tsakiris’Style. The temperature profile is separated from the geometrical factors in the case of vacuum cylinder and small target ball. It is demonstrated how the geometrical factors influence the irradiation nonuniformity with lapse of time. The misalignment and energy imbalance produces odd order rms variation. It is also found that those locations of X ray converters, which have minimum value of rms variation, move toward the edge of cylinder with lapse of time. This suggests that the expansion of wall pla