Re: Conversion of Half-life Years to Seconds

[Dimiter Popoff <tgi@cit.bg>]

Leo Lowe,



now that you know you have asked the wrong question, may I re-ask it:



> Which "year" is used by the standards organizations, such as NIST, when

> publishing half-lives?



Several years back, when I was writing my spectrum evaluation software,

I programmed the interactive nuclide library to switch the unit of the

half-life every time you click it. 

 I had the same question then - but given the issue was of no analytical

concern, I just took 365.25 days/year and called it a day. Also, this was

the better choice for me because in the sample report you can click and

edit the date of any isotope and see what its activity was/will be then;

this implies 365.25 precisely.



 I certainly would be curious if there is a "standard" for that.



Dimiter



--------------------------------------------------------------------

Dimiter Popoff

Transgalactic Instruments, Gourko Str. 25 b, 1000 Sofia, Bulgaria

http://transgalactic.freeyellow.com









> I want to calculate relatively precisely the specific activities of

> radionuclides with half-lives that are given in units of years.  This

> requires a conversion from "years" to seconds.

>

> So which "year" should I use: the calendar year (365 days), the mean solar

> year (365.24219 days), the sidereal year (365.25636 days), ....?  (where 1

> day = 24 hours = 86,400 seconds).

>

> Which "year" is used by the standards organizations, such as NIST, when

> publishing half-lives?

>

> Regards,

>

> Leo M. Lowe, Ph.D., P.Phys.

> Principal, Senior Health and

> Environmental Physicist

>

> SENES Consultants Limited

> 121 Granton Drive, Unit 12

> Richmond Hill, Ontario

> Canada L4B 3N4

> Tel:    (905) 764-9380

> Fax:    (905) 764-9386

> llowe@senes.ca

> www.senes.ca

>



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