If you use a Kimwipe for your wipe test the width of the wipe might be approximately 1 cm. Training Provided by the Principal Investigator Specific training for each laboratory will be given by the principal investigator for that laboratory. The basic principles for reducing a possible radiation dose from external sources are described by the rules for time, distance, and shielding. Practice runs without source may help to reduce exposure times when an actual experiment is performed. If limitation of the stay time in the vicinity of an external radiation source is not possible due to the required time to perform a given task, then other means of exposure reduction should be utilized.
Distance is a simple, inexpensive, and very effective way of dose reduction.
Alpha radiation requires no shielding. High beta radiation can be effectively shielded by low atomic number material such as Lucite and plastic. Gamma and x-rays however require a high density material such as lead. Shielding can be very effective to reduce exposure but it may be more expensive. Shielding material selection is dependent on the type and energy of radiation.