X-ray spectrometry for calculating conversion coefficients from air kerma to operational quantities in radiation protection.

This study explores the conversion coefficients from air kerma to operational quantities for radiation protection, using x-ray spectrometry for the narrow-beam qualities below 300 keV as defined by ISO 4037-1. By employing custom spectral correction algorithms combined with modern cadmium telluride (CdTe) semiconductor detectors, we effectively corrected spectral distortions caused by detection processes, ensuring more reliable measurements. These measurements are crucial for meeting radiation protection standards.

Characterization of an Innovative Detector Based on Scintillating Fiber for Personalized Computed Tomography Dosimetry.

For technical and radioprotection reasons, it has become essential to develop new dosimetric tools adapted to the specificities of computed tomography (CT) to ensure precise and efficient dosimetry since the current standards are not suitable for clinical use and for new CT technological evolution. Thanks to its many advantages, plastic scintillating fibers (PSF) is a good candidate for more accurate and personalized real-time dosimetry in computed tomography, and the company Fibermetrix has developed a new device named IVISCAN based on this technology. In this study, we evaluated performances of IVISCAN and associated uncertainties in terms of dose-rate dependence, angular dependence, stability with cumulative dose, repeatability, energy dependence, length dependence, and special uniformity in reference and clinical computed tomography beam qualities.

Dosimetry formalism and calibration procedure for electronic brachytherapy sources in terms of absorbed dose to water.

The LNE-LNHB has developed a methodology to standardize electronic brachytherapy sources in terms of absorbed dose to water. It is based on the measurement of the air-kerma rate at a given distance from the source and the Monte Carlo calculation of a conversion factor. This factor converts the air-kerma in measurement conditions into absorbed dose to water at a 1 cm reference depth in a water phantom.

Enhancement of IUdR Radiosensitization by Low-Energy Photons Results from Increased and Persistent DNA Damage.

Low-energy X-rays induce Auger cascades by photoelectric absorption in iodine present in the DNA of cells labeled with 5-iodo-2'-deoxyuridine (IUdR). This photoactivation therapy results in enhanced cellular sensitivity to radiation which reaches its maximum with 50 keV photons. Synchrotron core facilities are the only way to generate such monochromatic beams.

Measurement of (241)Am L X-ray emission probabilities.

Measurements of (241)Am L X-ray emission probabilities were conducted using both HPGe and Si(Li) detectors. The efficiency calibrations of these detectors were performed by means of a tunable, monochromatic photon beam and the determination of the thickness of absorbing materials inside the detector. These efficiency calibrations were obtained without any reference to radionuclide decay data, and with 0.

Comparative study of two drying techniques used in radioactive source preparation: freeze-drying and evaporation using hot dry nitrogen jets.

Quantitative solid sources are used widely in the field of radionuclide metrology. With the aim to improve the detection efficiency for electrons and x-rays, a comparative study between two source drying techniques has been undertaken at LNE-Laboratoire National Henri Becquerel (LNE-LNHB, France). In this paper, freeze-drying using commercial equipment is compared with a system of drying using hot jets of nitrogen developed at Institute for Reference Materials and Measurements (IRMM, Belgium).

Study of scattering effects in low-energy gamma-ray spectrometry.

The photon-scattering effect was studied in the low-energy range 15-80keV with planar and coaxial germanium detectors. Different experimental tests have been conducted with a point source, progressively reducing the matter around the radioactive deposit, to investigate the origin and characteristics of the different spectrum components due to scattered photons (bumps). These tests were completed by Monte Carlo simulations.

Standardization of (67)Ga using a 4pi(LS)beta-gamma anti-coincidence system.

(67)Ga is an interesting radionuclide as it is widely used in nuclear medicine. The meta-stable level related to the 93.3keV gamma-transition represents the main difficulty when using the coincidence method to standardize this radionuclide.

High-energy resolution alpha spectrometry using cryogenic detectors.

Applications such as environment monitoring implying alpha emitters activity measurement associated with isotope identification, require high-energy resolution detectors. Conventional silicon detectors are inexpensive therefore widely used, although intrinsically limited in energy resolution. Thermal detection principle of cryogenic detectors introduces a breakthrough in alpha particle measurement.

Experimental validation of coincidence summing corrections computed by the ETNA software.

The ETNA software has been developed to compute efficiency transfer and coincidence summing corrections. Different experiments are combined to test the validity of this last facility. Point sources with multi-gamma emitters are measured at several source-to-detector distances.

Metrological characterization of the ADONIS system used in gamma-ray spectrometry.

In gamma-ray spectrometry, new acquisition systems based on digital signal processing are now commercially available. In order to determine their performance at high count rates, the Commissariat à l'Energie Atomique (CEA), Laboratoire National Henri Becquerel has tested several of these systems. These tests have clearly shown that the performance levels announced by the manufacturers were generally not met.

A tunable monochromatic X-ray source for metrological studies in the 1-20 keV energy range: application to the measurement of attenuation coefficients.

A tunable monochromatic X-ray source operating in the 1-20 keV energy range is described. An X-ray tube provides initial photons. A dispersive crystal performs the energy selection, according to Bragg's law.

Intercomparison of efficiency transfer software for gamma-ray spectrometry.

The EUROMET project 428 examines efficiency transfer results for Ge gamma-ray spectrometers when the efficiency is known for a reference point source geometry. For this, different methods are used, such as Monte Carlo simulation or semi-empirical computation. The exercise compares the application of these methods to the same selected experimental cases to determine the usage limitations versus the requested accuracy.

Efficiency transfer and coincidence summing corrections for gamma-ray spectrometry.

ETNA (Efficiency Transfer for Nuclide Activity measurements) is a new computer program providing both detector efficiency transfer for various types of sources for coaxial source-detector geometries and coincidence summing corrections. This program, available for use on PCs, has a direct link to the computerised database NUCLEIDE in order to automatically import the necessary radionuclide decay data. The specific features and facilities are outlined and examples are given.

Results from the EUROMET action 410 concerning the decay data of 169Yb.

An international comparison EUROMET, action No. 410, was organized with the objective of improving the knowledge of nuclear data for 169Yb decay. To determine the photon emission probabilities, the participants were asked to measure at least one of the quantities, activity per unit mass and/or photon emission rate per unit mass.

Cryogenic detectors below 100 mK for X-ray measurements in metrology.

Due to the intrinsic performances of cryogenic detectors such as energy resolution, LPRI has decided to use these devices to improve the quality of the radioactive measurements usually obtained with classical semiconductor detectors. A bolometer with a 10 microg tin absorber has been developed at IAS (Institut d'Astrophysique Spatiale) and has been tested in the cryogenic installation of LPRI; an energy resolution (full width half maximum, FWHM) of 39 eV has been obtained on the Kalpha line of Mn. Besides these good spectrometry results, an absolute activity measurement using bolometers is proposed by adapting an absorber geometry for 4 pi counting.