A Method of determination of ambient quality factor of fast neutrons in mixed radiation fields using advanced recombination methods

Abstract The results reported herein demonstrate the potential application of combined optically stimulated luminescence/thermoluminescent (OSL/TL) measurements in neutron-gamma discrimination dosimetry. The advantages of OSL/TL are two-fold: (i) The OSL and TL readout can be carried out on the same sample and (ii) the greater efficiency of OSL to high ionization density radiation due to F 2 and F3 excitation. The gamma/electron calibration coefficients for LiF:Mg, Ti (TLD-600 and TLD-700) were measured using a 90Sr/90Y source calibrated at the SARAF-SSDL nuclear facility. The estimation of the neutron calibration coefficients was carried out by irradiation with broad-spectrum beam of fast neutrons with median energy 5 MeV at the Radiological Research Accelerator Facility (RARAF) of Columbia University. Naturally cooled samples of TLD-600 and TLD-700 were dosed to levels of 29.8 Gy neutrons and 6.1 Gy gammas in air and KERMA calculations employed to transfer the levels of dose to6,7LiF. A figure of merit for fast-neutron/gamma ray discrimination was determined at 10.6 for TLD-700 in the current measurements. The use of combined TLD-600/TLD-700 allowed, as well, the determination of a considerable and somewhat unexpected thermal neutron component of 116 Gy in TLD-600.

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P385 A new and fast echocardiographic method of determination of the optimal atrio-ventricular delay in patients after biventricular stimulation

European Heart Journal ◽

10.1016/s0195-668x(03)93823-1 ◽

2003 ◽

Vol 24 (5) ◽

pp. 48

Author(s):

J MELUZIN

Keyword(s):

Biventricular Stimulation ◽

Method Of Determination

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Development of a method for multielemental determination in water by EDXRF with radioisotopic source of 238Pu.

Brazilian Journal of Radiation Sciences ◽

10.15392/bjrs.v7i2a.627 ◽

2019 ◽

Vol 7 (2A) ◽

Author(s):

Camilo Fuentes Serrano ◽

Juan Reinaldo Estevez Alvares ◽

Alfredo Montero Alvarez ◽

Ivan Pupo Gonzales ◽

Zahily Herrero Fernandez ◽

...

Keyword(s):

Thin Layer ◽

Expanded Uncertainty ◽

Considerable Decrease ◽

X Ray ◽

Precipitation Efficiency ◽

Method Of Determination ◽

Sensitivity Curves ◽

Order Of Magnitude ◽

Metrological Parameters

A method for determination of Cr, Fe, Co, Ni, Cu, Zn, Hg and Pb in waters by Energy Dispersive X Ray Fluorescence (EDXRF) was implemented, using a radioisotopic source of 238Pu. For previous concentration was employed a procedure including a coprecipitation step with ammonium pyrrolidinedithiocarbamate (APDC) as quelant agent, the separation of the phases by filtration, the measurement of filter by EDXRF and quantification by a thin layer absolute method. Sensitivity curves for K and L lines were obtained respectively. The sensitivity for most elements was greater by an order of magnitude in the case of measurement with a source of 238Pu instead of 109Cd, which means a considerable decrease in measurement times. The influence of the concentration in the precipitation efficiency was evaluated for each element. In all cases the recoveries are close to 100%, for this reason it can be affirmed that the method of determination of the studied elements is quantitative. Metrological parameters of the method such as trueness, precision, detection limit and uncertainty were calculated. A procedure to calculate the uncertainty of the method was elaborated; the most significant source of uncertainty for the thin layer EDXRF method is associated with the determination of instrumental sensitivities. The error associated with the determination, expressed as expanded uncertainty (in %), varied from 15.4% for low element concentrations (2.5-5 μg/L) to 5.4% for the higher concentration range (20-25 μg/L).

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