Problems with radioactive dating methods

19-Jun-2017 05:25

Unfortunately, the rare earths include some chemically very similar elements as contaminants, many of which are mildly radioactive.

The chemistry of lanthanum and its associated rare earths is so closely related that it is readily possible to have radioactive contaminants end up in the desired lanthanum salts used in making optical glasses.

The amount of such contaminants could also easily vary from batch to batch, depending on the degree of contamination in the original monazite or other mineral sources being used.

I don't think that the original levels of thorium or lanthanum specified for use in these lenses [e.g., in patent filings] is the cause of their radioactivity.

Sometimes I have kept copies in different formats of information on those sites.

Rather than let such information disappear into the ether, occassionally I have reproduced some or all of it here. If I have reproduced this inappropriately and you are its original author, please contact me and I will remove it.

But if you have a lens using early specialty glasses (wide angles, fast lenses..) from before the 1970s, you should consider checking your lens for radioactivity.

problems with radioactive dating methods-44

micromax tablet p650 online dating

Eventually a more highly radioactive equilibrium will be reached, as in the original radioactive ores.So it isn't the thorium or the lanthanum that causes the problem here.The radioactivity of these early lenses is caused by contaminants in the ingredients (e.g., thorium salts) used to make the early lenses.So over the years, your "hot" lenses are likely to get more radioactive rather than less. Lanthanum has two isotopes in its natural form, one of which is weakly radioactive.

Another source of rare earths such as lanthanum is cerite, which contains the element cerium.

These slightly radioactive elements such as thorium or rare earth elements such as lanthanum were used to produce desired highly refractive glasses.

Best regards, Kris Kris, Please post the images of your DKE.… continue reading »

Read more

Wij houden voor u een stevige vinger aan de pols bij actuele gebeurtenissen. Met de Leeuwarder Courant zit u dagelijks bovenop het actuele nieuws. Wekelijks ontvangt u extra specials over boeiende thema’s als wonen, gezondheid, cultuur en sport. Het hele jaar door kunt u kiezen uit interessante lezersreizen. U stapt dicht bij huis op en maakt kennis met medereizigers uit het noorden. Met de app LC Krant heeft u (welke dagen is afhankelijk van uw abonnement) toegang tot onze digitale editie.… continue reading »

Read more

HSC Programs transitioned to a new medical provider for 2018. HSC departments should be using the latest version of the HSC Freeze Form that was made available in December 2017.… continue reading »

Read more

Your site on CS is your place where friends and members can come to view all these items, to contact you, send you flowers, rate your photos and leave you comments, shouts, and testimonials.… continue reading »

Read more

The purpose of this thesis was to explore how Evagrius’ apophatic approach to the knowledge of God informs his ascetical concept of apatheia, a fusion of doctrinal reflection and spirituality.… continue reading »

Read more

I have 5.5 years’ experience as a middle school teacher and counselor.… continue reading »

Read more

They don't go bad or anything and after you take a glimpse at the stunning fatties online, you will understand that you will be spending it fast.… continue reading »

Read more