Fertilizer Tests

For those who haven't done this, take your detector to a store that sells fertilizers for plants and gardens. Some are fairly hot, since they contain phosphates derived from apatite mineral, which in turn usually contains uranium and thorium compounds. Sometimes, the radioactive content is rather high.

Right now, I have a plastic baggie of Miracle Grow under my LND7317 1.75" mica window pancake detector with a GK Plus. Here's a short table of readings. With this pancake detector, the background is usually 33 - 34 CPM. File is tab delimited from Excel 2016.

Terminal log file Brian Gage, GK Plus with LND7317
Date: 26/01/202009:1
Time CPM Average
09:21:04 97 105
09:22:04 92
09:23:04 110
09:24:04 93
09:25:04 125
09:26:04 107
09:27:04 109
09:28:04 107
09:29:04 116
09:30:04 105
09:31:04 95
09:32:04 101
09:33:04 98
09:34:04 100
09:35:04 91
09:36:04 111
09:37:04 96
09:38:04 97
09:39:04 116
09:40:04 100
09:41:04 118
09:42:04 94
09:43:04 110
09:44:04 131
09:45:04 95
09:46:04 118
09:47:04 110

As you can see, this fertilizer definitely puts out some gamma and beta radiation. Haven't tested for alpha yet, since keeping the powder in a plastic bag is less messy.