The NE2528/3A is used for the dosimetry of 2 to 10 MV X-rays, 137Cs and 60Co gamma ray beams. It has a fixed water equivalent depth of 5 cm along the beam axis, providing good characteristics for routine checks of the beam output. This phantom also uses a thin, acrylic sleeve to support the chamber (e.g. NE2577C or NE2581A) and is fitted with expansion vessels to extend the practical range of temperature and pressure.