Do you know what this is?
This is a replacement Coleman Lantern mantel; replaced when the old one gets damaged or burnt out. I didn't use them for that purpose.
The mantel exhibits a peculiar property in that it is slightly radioactive. Because high radioactive sources were tightly controlled and inventoried in my work I needed a quick OP/NO-OP method for checking radiation monitors such as a Gamma-Ray tool. Potting two of these together and placing them near the GR detector would quickly tell me that it worked by registering the counts. Also, the same potted mantels would sub for a source to troubleshoot Geiger-Mueller bundles.
In any case the mantels were NOT for calibration; test sources were used for that and those were tightly controlled.
Another "source" that oil well logging companies use is sand. Not just any sand but sand gathered from the beaches of Guarapari, Brazil and potted in a flexible blanket.
My start in electronics, as a Radio-TV Repairman's helper, in 1963.
ACME Radio and TV
127 N Carrollton Avenue
New Orleans 19, Louisiana
My boss and the owner of the shop was Victor Cangelosi, a fantastic guy. He needed a helper to carry TVs to and from customers' homes. My pay wasn't much, I believe it was about $15 per week during school year, increased to $20 summer. That wasn't much money but the benefits were great; I was learning electronics.
Not only did he pay me but he also gave me some of his test equipment such as a VTVM and a Hickok O-Scope. My text books were SAMS Photofacs, Riders Radio Manuals and the reference bible of consumer electronics, the RCA Tube Manual.
As I gained more knowledge Mr Cangelosi let me repair some radios, especially the FIVE TUBE types. Those are super easy to fix.
Everything came to a crashing end during Christmas vacation 1964. I was sick, laid up in bed and during that time Mr Cangelosi had a fatal heart attack. Three days passed and his son had a junk man clean up the shop and the adjoining house where hundreds of classic and antique radios were stored. The shop was cleared to the bare walls. My test equipment and my school science project got trashed! Customers' sets gone! We didn't have tags on individual sets as those got ripped off; the ID on customer sets were coded labels with an index in a book.
I tried to recover some of the "junk" but the bulldozers at the Almonaster dump already crushed it all.
Brilliant son, don't you think? He was a History Professor.
Science Project for school – ruined, with no time to re-do.