Alpha Particle training at Treasure Island was conducted in Building 343 in a chamber that held various devices that would expose different types of nuclear radiation and the students were required to find the source and determine the safe levels away from the source and mark those on the floor.
Generally counting devices were used that had three settings, the default was gamma and for beta particles you removed one of two slides of glass to take the beta reading and then remove the remaining slide to detect alpha particles. Usually that was not enough and so they conducted swipe tests whereby the instructor would place a powder containing alpha particles onto surfaces and the student would have to find it and take a swab. This test was done on all bases and ships as it is very important to find alpha particle radiation indicating the presence of a nuclear weapon. The last photograph of this article is from the USS Proteus a nuclear submarine showing the areas used for regular training in radiation detection.
This means they had to secure the gamma and beta sources the Cesium 137 sources (Cs 137) so a good reading can be made.
But because the radiation training involved direct exposure to all the safety requirements often resulted in instructors avoiding the swab tests as they took on larger doses if this was done regularly and hence the use of devices. The problem is that in order to test properly for alpha particles you need to do the swab tests. A problem to this day.
We know they did this training because of the devices were in the building and other reports where they detail the swab testing. Here is a diagram of the building, a notice about the devices used, a photograph of the building today and the instructions from United States. Army. U.S. Army Nuclear, Biological And Chemical School (AL,MD): Environmental Impact Statement. , 1979.
Note the cleanup broke into this building and ripped off the roof and broke into the “Radium Vault” which is between the two buildings in the mid left which contained all sorts of nuclear isotopes, probably still does and they in their recklessness damaged it not realizing it was fortified for a reason. They destroyed it with barbarism and ignorance.
Here are the exposures from the AN/UDM 1A exposure room amounts that the Navy admitted to in 1974 (below)
Note that the Treasure Island Development Board allowed the placement of the Treasure Island Skatepark to be made adjacent to the buildings used for radiation training to normalize the base, make it socially acceptable to live with the radiation without telling the youth that they are operating on not only a toxic waste site but a nuclear site as well. Here is the article