This listing is for the pictured thoriated glass lens extracted from a pre-1970s Canon camera lens.

Size: 21x7mm

Thoriated glass may contain up to 30% thorium by weight.

Thorium is an ideal source for the Radiacode 101 because it provides the three data points required for calibration at 88, 583 and 2614kEv.

We have many other scary sounding check sources but those are no longer allowed . Our online shop should be very easy to find.

For more information regarding measurements between Geiger counters, please search the web for "How Many CPM Should My Sample Read?" quotes included.

If the lens has developed a brown tint over time, the discoloration can be mitigated by exposing the lens to ultraviolet light.

This listing meets the requirements of NRC 10 CFR 40.22 It also meets U.S.P.S domestic shipping requirements for exempt limited quantities of class 7 materials according to –347.22 “are eligible under 49 CFR to be shipped as excepted packages for limited quantities” and –Exhibit 347.22 Activity Limits– and also –173.435– Table of A1 and A2 values