ANNALS OF “DUNAREA DE JOS” UNIVERSITY OF GALATI – FASCICLE II
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ANNALS OF “DUNAREA DE JOS” UNIVERSITY OF GALATI
MATHEMATICS, PHYSICS, THEORETICAL MECHANICS
FASCICLE II, YEAR I (XXXII) 2009
ANALYSIS OF CARBON IN METALLURGICAL SAMPLES
Corina Manea1, A. Popa2
1
Physics Department, University of Galati, 47 Domneasca St.,800008 Galati, Romania
2
Laboratoire d’Electronique, Université Le Havre, France
Abstract
The analytical use of prompt gamma rays arising from the nuclear reactions induced by proton
beam during the bombardment of steel targets has been investigated. Being an on-line technique,
the sensitivity of analysis using protons (PIGE) critically depends on the level of background
activities from the matrix nuclides under proton irradiation. Carbon can be determined in steel
from the very high yields of the 4439.1 keV (1,0) gamma-rays resulted from the reaction 12C (p,
p’) 12C, the excellent peak to background ratio and the absence of other peaks in the 3-4 MeV
energy range leading to a good sensitivity.
Keywords : metallurgical samples, carbon, analytical techniques,
1. INTRODUCTION
The measurement of low concentrations of light elements is often useful in materials science,
particularly in metallurgy. Methods for analysis of carbon in metals, alloys and semiconductor have
been actively investigated because of carbon’s effect on both physical and electrical properties of its
host matrix. Also, the properties of steels are critically dependent on their carbon content and its
spatial distribution.
Some of the analytical procedures that have been employed in the quantitative determination of
carbon include [1,2]: classical combustion techniques, Photon Activation Analysis (PAA) or Charged
Particle Activation Analysis (CPAA) using 6Li ions [1] and deuterons [2]. Some of the activation
techniques, although sensitive, are problematic due to interferences from oxygen and nitrogen present
in the sample. The combustion method can become unreliable at trace levels because of the limited
sensitivity and blank-value problems.
Neutron Activation Analysis (NAA) is, in general, a very sensitive method but has limited use
for light elements. Also, Particle-Induced X-ray Emission (PIXE) fails in the situation where the
species of interest has a low atomic number because the low carbon K X-ray fluorescence yield is
strongly attenuated by the absorption edge of higher atomic number elements present in the sample.
Ion beam Analysis (IBA) is often used and one of the first IBA technique on steel made use of
the 12C (p, ) 13N nuclear reaction [3]. The yield of this reaction is low and the sensitivity of the
method is poor. The (d,n) activation reaction have very high sensitivities, but because the only γactivities produced in these reactions, interfering activities (especially those from other light
elements) might necessitate tedious time-decay analyses [4]. Prompt γ-ray analysis (PIGE) offers an
alternative in measuring light elements and has the advantage that γ-rays from the different light
elements can be easily distinguished by their energies [5,6]. Nuclear Reaction Analysis (NRA) allows
the determination of light element concentrations in heavier element substrates, providing a depth
distribution of the isotope of interest [7,8].
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2. EXPERIMENTAL
The 5.5 MeV proton and 5 MeV deuteron beams have been generated with the aid of the 7 MV
FN tandem accelerator of the “Horia Hulubei” National Institute of Physics and Nuclear Engineering
(NIPNE) Bucharest. The beam current was below 10 nA. Prompt -rays produced in the steel plate
samples and standards provided by specialists from ISPAT-SIDEX Iron and Steel Works of Galaţi
(Romania) and prepared as thick targets, were measured with a GeHP detector having an active
volume of about 100 cm3 and an energy resolution of 2 keV at 1.33 MeV, placed at 90 with respect
to the beam.
The heat exchange coefficient, α, was determined using the relation:
  Nu 


[W/m2K]
(1)
where: λ is the thermal conductibility of the fluid, in [W/m.K];  - the determinative length of the
heat exchange (the dimension along the direction of the fluid flow), in [m]; Nu – the Nusselt criterion,
Nu  0.151 Re 0.8  Pr 0.75 (2)
wd
(3)
Re 

3. RESULTS AND DISCUSSION
Details of the prompt -rays spectra obtained during the bombardment of a steel standard having
a carbon content of 670 ppm, with 5.5 MeV protons are presented in Fig. 1 and the -ray lines in the
spectra used to identify carbon in steel are labelled in accordance with the convention AX (p,b) (t, s)
where AX is the target nuclide; b – the emitted nuclear product particle in the nuclear reaction induced
by incident particle p (protons or deuterons); t and s – the level numbers in the heavy product nucleus
between which the  transition occurs.
Gamma energies corresponding to the transitions in the nuclei of interest were extracted from
the nuclear level schemes [12] and from the yields of prompt gamma-rays resulted from the irradiation
of pure elemental targets with protons [13] and deuterons [14].
Fig.1. The main sources of CO2
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Table 1. The main substances with an important role in the modifications produced in the
atmosphere
Chemical
Compound
Formula
Role in Tropospheric Chemistry
Carbon dioxide
CO2
Carbon dioxide in the troposphere is produced by photosynthesis by plants and
microbes, by decomposition of organic matter, and by fossil fuel combustion. CO2 is
an important greenhouse gas.
CO
Carbon monoxide comes from wildfires, volcanoes, and incomplete combustion in
the exhaust gases from cars and trucks. It is poisonous and can raise the levels of
greenhouse gases via certain chemical reactions. It reacts with oxygen to transform
into carbon dioxide
Hydrocarbons
CxHy
Hydrocarbons are released by the combustion of fossil fuels. They are constituents
for smog. Hydrocarbons are combinations of hydrogen and carbon atoms.
Hydrogen
Peroxide
H2O2
Hydrogen peroxide, often present in small quantities in water droplets in the
atmosphere, creates sulfuric acid in acid rain in reaction with sulfur dioxide.
Methane
CH4
Methane is a powerful greenhouse gas. Although its concentration in the atmosphere
is small, it has a substantial impact on Earth's energy balance.
Nitrogen
N2
Carbon
monoxide
Nitrogen oxides NO;
NO2
78% of the gas molecules in the troposphere are nitrogen. Nitrogen atoms move
through the environment via the nitrogen cycle. Hot combustion, such as in auto
exhausts, incorporates nitrogen into nitrogen oxides.
Nitrogen oxides form during high-temperature combustion in air, such as in
automobile exhausts. They form smog and mixed with water create nitric acid, a
component of acid rain.
4. CONCLUSIONS
Methods for analysis of carbon in metals, alloys and semiconductor have been actively
investigated because of carbon’s effect on both physical and electrical properties of its host matrix.
Also, the properties of steels are critically dependent on their carbon content and its spatial
distribution.
References
1. Thomas B. G., Continuous Casting of Steel, Chapter 15 in: Modeling for Casting and
Solidification Processing (O. Yu, editor), Marcel Dekker, New York, NY, pp. 499-540,
2001.
2. Derem A., Théorie de la matrice S et transformation de Sommerfeld – Watson dans la
diffusion acoustiques, La diffusion acoustique, Paris, 1987.
3. Danila E. B., Théorie de la diffusion résonnante multicanaux. Application à la diffusion
acoustique par un tube élastique aux parois excentrées, Thèse de Doctorat de l’Université du
Havre, 1996.
4. Franklin H., Conoir J.-M., Izbicki J.-L., Two-channel resonant scattering theory: Application
to an absorbing elastic cylinder, J. Acoust. Soc. Am. 102 (1997) 87-95.
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