Described is a portable dosimeter reader that is small in size and light in weight comprising an optically stimulated luminescence (OSL) reader for reading one or more OSL sensors of a dosimeter sled. The portable dosimeter may also include a sled slider that is driven by an engine to position in turn each of the one or more OSL sensors of the dosimeter sled at a reading position where the OSL reader reads each respective OSL sensor. A display may be provided for displaying information relating to reading the one or more OSL sensors. The portable dosimeter may also include a battery compartment for one or more batteries and a case enclosing the device.