Authors:György Zoltán Radnóczi, Zoltán Herceg, and Tamás Rafael Kiss
modern microscopes is usually around 1–2%. This accuracy is only achieved if strict imaging requirements are met regarding sample height and defocus. This may be improved by the use of accurate calibration standards like the commonly known Mag
Authors:N. Krasnov, B. Zatolokin, and I. Konstantinov
It is shown that three different approaches to calibration technique based on the use of average cross-section, equivalent
target thickness and thick target yield are adequate. Using the concept of thick target yield, a convenient charged particle
activation equation is obtained. The possibility of simultaneous determination of two elements impurities, from which the
same isotope is formed, is pointed out. The calibration technique, in which thin standard is used but activation curve is
not required, is discussed.
The development of methods for temperature and heat calibration of DSC and DTA supported by the German Society of Thermal Analysis (GEFTA) are presented. Reasons are given for the recommendation of the temperature calibration method, which refers to the valid international temperature scale (ITS 90) and takes into account the fact that the fixpoints of this scale are defined in two phase equilibrium.
The absolute total and full-energy peak (FEP) efficiencies of a high purity germanium (HPGe) photon detector are measured in the energy range from 40 keV to 1500 keV. The functional parameters are fitted to the calibration points from 14 long-lived standard sources (129I,241Am,109Cd,57Co,139Ce,137Cs,54Mn,65Zn,60Co,22Na,133Ba,152Eu,154Eu and166mHo) within an accuracy better than the quoted uncertainty of the calibration sources. The efficiencies in far and close geometries are compared.
Authors:Marian Calin, Mihaela Calin, Laurentiu Done, Alexandru Druker, and Adrian Calin
The Gamma-ray spectrometers are complex instruments and the quality of the data they provide depends strongly on their proper calibration.
This paper describes the energy and efficacy calibration of two gamma-ray spectrometers in order to validate the method for measuring the activity of gamma-ray emitting radionuclides. The punctiform
standard sources 60Co, 133Ba, 137Cs and 241Am were used in this study. Minimum Detectable Activity, Peak to Compton Ratio and the peak shape parameters were determinate.
An inter-comparison of the results obtained with both systems was done. The results demonstrated that the activity values
are comparable with low errors respecting with those for conventionally true activities.
Authors:Hong Le Khiem, Nguyen Van Do, and Pham Khue
A method for detector calibration in radiation measurements of large samples by Monte-Carlo calculation is presented. This method is useful in the absolute radioactivity measurements when the relative method cannot be applied as suitable large standard samples are not available.
Authors:S. Miljanić, D. Ražem, and M. Ranogajec-Komor
Precise dosimetric calibration of the radiation field of the Gammacell irradiator has been carried out. For measuring spatial dose distribution a cavity ionization chamber in conjuction with a Farmer dosimeter and CaF2 thermoluminescent dosimeters were used. The results make possible the calculation of doses received by samples of different sizes and shapes.
The precision obtainable by instrumental neutron activation analysisdepends strongly on the quality of the calibration of the gamma-ray spectrometerused for measuring the irradiated samples. Even when relative standardizationis employed, practical experience has shown the importance of detector calibration.This is especially relevant when radionuclides of varying activities are involved.The problems often encountered are those of intolerable high dead time andthe occurrence of summed peaks in the gamma-ray spectra. A simple but accuratesemi-empirical formula is presented that could effectively predict the efficiencyof a detector at any source-to-detector distance. Experimental data obtainedat 0, 50, 100, 200 mm source-to-detector distances are used to demonstratethe usefulness of this formulation. In addition, nine elements were analyzedin the NIST Orchard Leaves using absolute standardization including four elementsSm, Ta, Au, and La for which no certified values could be obtained.
The temperature calibration of a TA Instruments 3200-2920 DSC has been performed on cooling using the isotropic → nematic,
isotropic → cholesteric and other liquid crystal → liquid crystal transitions of thermally stable, high purity liquid crystals.
The thermal stability of these liquid crystals has been verified by measuring the temperature of the mentioned transitions
during cyclic heating and cooling experiments. Correspondence has been established between the real and indicated temperature
during cooling for all combinations of heating and cooling rates of practical interest: correction values were determined
to the indicated temperature in order to obtain the real temperature on cooling. These correction values were calculated as
the average from the temperatures of four or five different liquid crystal transitions for each heating-cooling rate combination.
The accuracy of the temperature calibration on cooling is ca. 0.2‡C for heating and cooling rates up to 20‡C min−1.
Disintegration, ventilation and deposition were considered as removal processes of the radon and its short-lived daughters in air and the respective concentration equations were applied. Calibration coefficient (KF) of the solid state nuclear track detector (SSNTD) LR-115 for radon and the equilibrium factor (F) were related to track densities of the bare detector (D) and the filtered one (Do). A useful relationship between KF, F and detector sensitivity coefficient (k) was derived. Using the calibrated value k=3.29×10–3 m, the exposed detectors gave the average values of the equilibrium factor, calibration coefficient and indoor radon concentration of a single house living room in Osijek 0.46, 142.3 m–1 and 37.8 Bq m–3, respectively.