Navigation Links
Accurate measurement of radioactive thoron possible at last
Date:3/7/2011

"Many people are now saying: 'Is it really that easy? Then why didn't anyone think of it a long time ago?' But you have to have the right idea at the right time," says Annette Rttger, physicist at the Physikalisch-Technische Bundesanstalt (PTB), in a pleased way. Annette Rttger and her scientific team managed to do something that was previously thought to be impossible: they developed a primary standard for the measurement of short-lived radioactive thoron. Thoron measuring instruments from all over the world will now be calibrated at this unique device which is currently the only one of its kind in the world. This is the basis for accurate measurements of radioactive gas, which occurs naturally in the ground, can collect in living areas and whose progenies are considered carcinogenic.

The same as its sister isotope radon (Rn-222), the radioactive gas thoron (Rn-220) can also cause lung cancer through its progenies if these are breathed in over long periods of time and in high concentrations. The degree of the radiation exposure of living areas varies greatly and is dependent on the construction of the house and the way it is ventilated. The measurement of Rn-222 has worked very accurately for a long time, whereas measuring instruments for thoron have delivered results with considerable uncertainties up till now. And what was worse: sometimes the results were simply wrong! The exact measurement of thoron is, however, important for the estimation of risks, as at the same activity concentration, a 14-fold higher radiation level results from the thoron progenies than from the progenies of the Rn-222, which is already measured well.

"It was clear that all thoron measuring instruments need a uniform standard with which they can be calibrated so that all the measurements are comparable, and so that you know the uncertainty of each individual measuring instrument," explains Annette Rttger. But the development of a standard that is valid everywhere metrologists speak of a primary standard like the one that already exists for Rn-222, was considered impossible for a long time, because thoron has a relatively short half-life of only 55 seconds. The PTB team finally had a brilliant idea:

The core of the primary standard is a test container which is filled with a defined amount of thoron. In view of the short half-life, a closed container, such as for radon, did not come into question, as the activity would quickly decay in that, in a short time. For this reason the scientists developed a circuit system that constantly introduces newly produced thoron with a high flow air stream and keeps the activity in the container constant.

The production and the accurate measurement of the activity which was fed in, was a metrological challenge. It was possible through a novel measuring arrangement called the thoron emanation measuring facility (TEM). The activity thereby comes from a thorium (Th-228) preparation which continually produces thoron. A constant, strong air stream transports the thoron into the test container. The tough nut that had to be cracked was: how much thoron is transported away and how much stays in the source? The PTB team finally succeeded in determining this ratio to one tenth of a per cent exactly.

Parallel to operating the TEM, the measuring instrument to be calibrated can be connected to the test container. As a rule, all the connected devices show more or less different results. You might even have a factor of 4! The manufacturers then receive a correction factor from PTB with which they have to multiply the measurement result to get to the correct result.

As more and more geological and epidemiological studies in Asia, Europe and Latin America are focussed on thoron (to which little attention had been paid to date), the newly set up measuring arrangement at PTB is constantly fully booked by international customers.


'/>"/>

Contact: Dr. Anntette Roettger
annette.roettger@ptb.de
49-531-592-6130
Physikalisch-Technische Bundesanstalt (PTB)
Source:Eurekalert

Related medicine news :

1. Rapid Flu Test Most Accurate for Young Kids
2. LifeScan Recalls Specific Lots of Consumer and Professional OneTouch(R) SureStep(R) Test Strips Due To Inaccurate Readings at High Levels
3. Study: Mechanomyography to be accurate in detecting nerves during minimally invasive spine surgery
4. Whole body MRI is highly accurate in the early detection of breast cancer metastases
5. Innovative Technology Developed at AGH Accurately Monitors Healthcare Professionals' Handwashing Practices, Study Shows
6. Survey: Many Young Women Lack Accurate Information about STDs
7. Study finds cancer information on Wikipedia is accurate, but not very readable
8. New formula gives first accurate peak heart rate for women
9. Latino children with asthma less accurate in determining their lung function
10. Experimental TB Test Called Fast and Accurate
11. Blood test accurately predicts death from prostate cancer up to 25 years in advance
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:2/27/2017)... ... February 27, 2017 , ... This ... laser diffraction analysis as a tool to characterize particle size distributions in the ... obtain improved results and novel scientific findings. It describes methods of optimized and ...
(Date:2/27/2017)... ... February 27, 2017 , ... Silicon Valley Hair Institute, a ... new informational post on robotic hair transplantation. San Francisco residents may be confused ... Follicular Unit Transplantation (FUT) can sound similar. Either treatment can be used to ...
(Date:2/26/2017)... ... February 26, 2017 , ... ... lab became the world’s first to be ISO/IEC 17025:2005 INAB accredited for Der ... , ISO/IEC 17025:2005 is the globally recognised standard that sets out requirements for ...
(Date:2/26/2017)... ARLINGTON, VA (PRWEB) , ... February 26, 2017 , ... ... Medicaid Managed Care Summit, February 27-28 at the Sheraton Pentagon City Hotel in Arlington, ... work with PerformCARE to use behavioral health analytics to improve Medicaid population health management. ...
(Date:2/24/2017)... ... February 24, 2017 , ... Houston dentist ... his office, Antoine Dental Center. Currently, patients can get single dental implants for ... but patients can learn more about these offers by contacting Antoine Dental Center. ...
Breaking Medicine News(10 mins):
(Date:2/27/2017)... Israel and TAMPA, Fla. , Feb. ... emerging medical device company focused on developing cerebral ... applauds the members of the FDA,s Circulatory System ... their acknowledgement of the need for cerebral protection ... "The statements shared by this FDA panel ...
(Date:2/27/2017)... Feb. 27, 2017  Impax Laboratories, Inc. (NASDAQ: IPXL ) today ... Raymond James and Associates, 38 th ... 2017 in Orlando, FL. Cowen ... ET on March 7, 2017 in Boston, MA. ... 16, 2017 in Miami, FL. ...
(Date:2/27/2017)... 27, 2017  CTI BioPharma Corp. (CTI BioPharma) (NASDAQ and ... , M.D., Ph.D., as President and Chief Executive Officer (CEO) ... 2017. Dr. Craig succeeds Richard Love , interim President ... Board of Directors.  Dr. Craig has over 20 years of ... US and Europe . "On ...
Breaking Medicine Technology: