Articles (en)

Marie Curie 150 years (1867-2017)

Born 150 years ago in Poland, Marie Curie was the first woman to teach in higher education, but above all she was the only one to receive two Nobel Prizes: the first in physics in 1903, with her husband Pierre, and the second in chemistry in 1911.
She manufactured and certified the first radium standard and, during the First World War, she contributed to the development of medical imaging by setting up radiological cars that travelled across the battlefields to detect shrapnel from wounded soldiers.
She perfectly represents all the perseverance and skill needed to study radioactivity and its applications.

Find some information about her life in the following links:
A short biography on Franceinfo.fr: Marie Curie, the first woman to win a Nobel Prize (fr)
An article by Bert M. Coursey in Applied Radiation and Isotopes: A reflection on the 150th anniversary of the birth of Marie Curie
On francetvéducation.fr: Curies’ first research on radioactivity (fr)
On FranceInter.fr: Sur les épaules de Darwin – Discovering radioactivity (March 26, 2016 broadcast)
Check out the Curie Museum’s 2017/2018 cultural programme dedicated to the 150th anniversary of Marie Curie.
First report by Marie Curie to the Académie des sciences on April 12, 1898: Radiation emitted by uranium and thorium compounds (fr)

Q spectrometry

Background
Isotopic analysis of actinides is commonly used in the nuclear fuel cycle or for the control of the Nuclear Non-Proliferation Treaty. Current conventional techniques, mass and alpha spectrometry, are sometimes limited by spectral interferences. The objective is therefore to develop a new technique for the analysis of total decay energy by spectrometry. Thanks to the high resolution of the magnetic calorimeters developed at LNHB, it will be possible to distinguish and quantify all alpha-emitting actinides present.

Achievements
A prototype magnetic calorimeter was developed and tested with a 210Po electro-deposited source integrated into a silver absorber. The measurement of the spectrum of total decay energy was obtained in the 10 mK dilution refrigerator.

Major results
The spectrum obtained showed a resolution of 0.9 keV at an energy of 5.4 MeV, a resolution one order of magnitude better than that of a semiconductor alpha detector. This detector thus offers one of the best performance in the world in terms of resolution.
The aim is now to demonstrate performance on mixtures of actinides and to simplify the integration of sources in absorbers in order to bring this technique towards a competitive use compared to the usual techniques.

Portable TDCR

The measurement of radiopharmaceuticals used in nuclear medicine services is generally done through calibrated dose calibrators linked to the SI by the LNHB. Short half-life radionuclides, such as 11C (T1/2 = 20 min) or 15O (T1/2 = 2 min), are produced in situ and are difficult to transport for calibration in a primary laboratory. For these reasons, it was necessary to develop a portable primary measuring device that could be used on site.

Achievements:
Design of the portable system.
Optimization for the measurement of short half-life radionuclides:
– use of compact photomultipliers,
– integration in a polymer mechanical system,
– manufacturing by fused deposition modeling (3D printing),
– integration of miniature acquisition electronics, coupled to a laptop PC.

 

Major results:
Validation of a prototype by comparison with the laboratory’s TDCR primary measurement system.
The next developments should make it possible to couple this measuring device with a microfluidic sampling system to limit the irradiation dose to operators and to limit the quantities of solution that are consumed for quality control.

REFERENCES:
– Broda R., Cassette P., Kossert K. Radionuclide metrology using liquid scintillation counting. Metrologia, 44 (4) (2007)
– Marco Capogni, Pierino De Felice, A prototype of a portable TDCR system at ENEA, Applied Radiation and Isotopes, Volume 93, 2014, Pages 45-51
Collaboration with Sofia University

New metrological references for radiotherapy

The photon beams delivered by the Varian TrueBeam medical accelerator installed on the DOSEO platform are now the reference beams used for calibration of clinical radiotherapy centres. This required new metrological references in terms of absorbed dose in water.

Achievements:
Water and graphite calorimeters are used at LNHB as primary instruments for photon and electron beam measurements of the absorbed dose in water.
In the case of the Varian TrueBeam accelerator, calorimeters were used to determine the calibration coefficients in absorbed dose to water of 3 reference ionization chambers for the different beam qualities delivered (6, 10, 15 and 20 MV). They are plotted according to a beam quality index called TPR20,10 (Tissue Phantom Ratio 20,10).

 

Major results:
The uncertainty obtained on the calibration coefficients of the ionization chambers is about 0.5%.
The results showed a good agreement with the calibration coefficients previously obtained from graphite calorimeters on the beams of the old LNHB accelerator (Delphes, Saturne 43).
The equipment redundancy (graphite and water calorimeter) at LNHB is unique in Europe. It provides references based on two independent methods and thus consolidates its references by improving the control of uncertainties for the calibration of clinical centres.

ICRM 2017

The LNHB attended the 21st International Conference on Radionuclide Metrology and its Applications
From 15th to 19th of May, 2017. Buenos Aires – Argentina

Find all the information here

Thoron primary measurement

The concentration of thoron in France is estimated to be one-tenth that of radon and is therefore a significant public health issue. To meet the need for traceability of measurements of this natural thorium descendant, a new primary standard instrument has been developed and validated at the LNHB to calibrate the instruments for measuring thoron volume activity in air.

Achievements:
– Creation of an adapted thoron measurement system (short half-life: 55.8 s)
– Complete study of the nuclear properties of radon, thoron and their progeny
– Description of charge distribution of thoron progenies nano-particles and their transport in air

Major results:
Analysis of the alpha spectra obtained made it possible to accurately qualify the volumic activity of a thoron atmosphere with an associated 1% relative standard uncertainty. The portable device thus made it possible to calibrate the thoron atmosphere produced in the Baccara facility, the experimental radon chamber of the IRSN Aerosol Physics and Metrology Laboratory (LPMA) dedicated to radon metrology studies.
Comparisons with ENEA (Italy) in the MetroNORM European Metrology Project

REFERENCES:
This work has been supported by the European Metrology Research Programme (EMRP), JRP-Contract IND57 MetroNORM (http://metronorm-emrp.eu/).
– Sabot B., Pierre S., Michielsen N., Bondiguel S., Cassette P., (2015), Development of a primary thoron activity standard for the calibration of thoron measurement instruments, Radiat Prot Dosimetry 167 (1-3), 70-74.
https://doi.org/10.1093/rpd/ncv221
– Sabot B., Pierre S., Michielsen N., Bondiguel S., Cassette P., (2016), A new thoron atmosphere reference measurement system, Appl Radiat Isot. 109, 205-209.
http://dx.doi.org/10.1016/j.apradiso.2015.11.055
– Sabot B., (2015), Calibration of thoron (220Rn) activity concentration monitors, PhD Thesis,
http://www.theses.fr/2015SACLS122