Element¶

class curie.Element(element)[source]¶

Elemental data and properties

The Element class provides useful data about the natural elements, such as mass, density, and isotopic composition. Additionally, it contains functions for determining the interaction of radiation with the natural elements. Principally it provides the mass-attenuation of photons, and the stopping power/ranges of charged particles.

Parameters:

elementstr: Symbol for the element, e.g. ‘H’, ‘In’, ‘Zn’, ‘Fe’. Case insensitive. Note that ‘n’ (“neutron”) is not considered a valid element in this context, and will be interpreted as ‘N’ (“nitrogen”).

Examples

>>> el = ci.Element('Fe')
>>> print(el.mass)
55.847
>>> print(el.density)
7.866

Attributes:

namestr: Symbol for the element, in title-case. E.g. if input was ‘fe’, name will be ‘Fe’.
Zint: Atomic number of the element.
massfloat: Molar mass of the natural element in atomic mass units (amu).
isotopeslist: List of isotopes with non-zero natural abundance.
abundancespd.DataFrame: Natural abundances, in percent, for all isotopes found in nature. Structure is a DataFrame with the columns ‘isotope’, ‘abundance’, and ‘unc_abundance’.
densityfloat: Density of the natural element in g/cm^3. The density is used in calculations of charged particle dEdx and photon attenuation, so you can assign a new density using el.density = new_density if needed, or using the density keyword in either of those functions.
mass_coeffpd.DataFrame: Table of mass-attenuation coefficients as a function of photon energy, from the NIST XCOM database. Energies are in keV, and mass-attenuation coefficients, or mu/rho, are given in cm^2/g. DataFrame columns are ‘energy’, ‘mu’ and ‘mu_en’ for the mass-energy absorption coefficient.

Methods

`S`(energy[, particle, density])	Charged particle stopping power in matter
`attenuation`(energy, x[, density])	Photon attenuation in matter
`mu`(energy)	Mass-attenuation coefficient
`mu_en`(energy)	Mass energy-absorption coefficient
`plot_S`([particle, energy])	Plot the stopping power in the element
`plot_mass_coeff`([energy])	Plot the mass-attenuation coefficient in the element
`plot_mass_coeff_en`([energy])	Plot the mass energy-absorption coefficient in the element
`plot_range`([particle, energy, density])	Plot the charged particle range in the element
`range`(energy[, particle, density])	Charged particle range in matter

S(energy, particle='p', density=None)[source]¶

Charged particle stopping power in matter

Calculate the stopping power, S=-dE/dx, for a given ion as a function of the ion energy in MeV. Units of S are MeV/cm. To return stopping power in units of MeV/(mg/cm^2), use option density=1E-3.

Parameters:

energyarray_like: Incident ion energy in MeV.
particlestr, optional: Incident ion. For light ions, options are ‘p’ (default), ‘d’, ‘t’, ‘a’ for proton, deuteron, triton and alpha, respectively. Additionally, heavy ions can be specified either by element or isotope, e.g. ‘Fe’, ‘40CA’, ‘U’, ‘Bi-209’. For light ions, the charge state is assumed to be fully stripped. For heavy ions the charge state is handled by a Bohr/Northcliffe parameterization consistent with the Anderson-Ziegler formalism.
densityfloat, optional: Density of the element in g/cm^3. Default behavior is to use Element.density. To return stopping power in units of MeV/(mg/cm^2), i.e. the mass-stopping power, use density=1E-3.

Returns:

stopping_powernumpy.ndarray: Stopping power, S=-dE/dx, for a given ion as a function of the ion energy in MeV. Units of S are MeV/cm.

Examples

>>> el = ci.Element('La')
>>> print(el.S(60.0))
36.8687750516453
>>> print(el.S(55.0, density=1E-3)) ### S in MeV/(mg/cm^2)
0.006371657662505643

attenuation(energy, x, density=None)[source]¶

Photon attenuation in matter

Calculate the attenuation factor I(x)/I_0 = e^(-mu*x) for a given photon energy (in keV) and slab thickness (in cm).

Parameters:

energyarray_like: Incident photon energy in keV.
xfloat: Thickness of slab of given element, in cm.
densityfloat, optional: Density of the element in g/cm^3. Default behavior is to use Element.density.

Returns:

attenuationnumpy.ndarray: The slab attenuation factor as an absolute number (i.e. from 0 to 1). E.g. if the incident intensity is I_0, the transmitted intensity I(x) is I_0 times the attenuation factor.

Examples

>>> el = ci.Element('Fe')
>>> print(el.attenuation(511, x=0.3))
0.821621630674751
>>> print(el.attenuation(300, x=0.5, density=8))
0.6442940871813587

mu(energy)[source]¶

Mass-attenuation coefficient

Interpolates the mass-attenuation coefficient, mu/rho, for the element along the input energy grid.

Parameters:

energyarray_like: The incident photon energy, in keV.

Returns:

munp.ndarray: Mass attenuation coefficient, mu/rho, in cm^2/g.

Examples

>>> el = ci.Element('Hg')
>>> print(el.mu(200))
0.9456

mu_en(energy)[source]¶

Mass energy-absorption coefficient

Interpolates the mass-energy absorption coefficient, mu_en/rho, for the element along the input energy grid.

Parameters:

energyarray_like: The incident photon energy, in keV.

Returns:

mu_ennp.ndarray: Mass energy absorption coefficient, mu_en/rho, in cm^2/g.

Examples

>>> el = ci.Element('Hg')
>>> print(el.mu_en(200))
0.5661

plot_S(particle='p', energy=None, **kwargs)[source]¶

Plot the stopping power in the element

Creates a plot of the charged particle stopping power (in MeV/(mg/cm^2)) in the element as a function of the incident ion energy (in MeV).

Parameters:

particlestr: Incident ion. For light ions, options are ‘p’ (default), ‘d’, ‘t’, ‘a’ for proton, deuteron, triton and alpha, respectively. Additionally, heavy ions can be specified either by element or isotope, e.g. ‘Fe’, ‘40CA’, ‘U’, ‘Bi-209’.
energyarray_like, optional: Energy grid on which to plot, replacing the default energy grid. Units are in MeV.

Other Parameters:

**kwargs: Optional keyword arguments for plotting. See the plotting section of the curie API for a complete list of kwargs.

Examples

>>> el = ci.Element('He')
>>> el.plot_S(particle='a')
>>> el = ci.Element('Fe')
>>> el.plot_S(particle='d')

plot_mass_coeff(energy=None, **kwargs)[source]¶

Plot the mass-attenuation coefficient in the element

Creates a plot of the mass-attenuation coefficient (in cm^2/g) as a function of photon energy in keV.

Parameters:

energyarray_like, optional: Energy grid on which to plot, replacing the default energy grid. Units are in keV.

Other Parameters:

**kwargs: Optional keyword arguments for plotting. See the plotting section of the curie API for a complete list of kwargs.

Examples

>>> el = ci.Element('Fe')
>>> el.plot_mass_coeff()
>>> el.plot_mass_coeff(style='poster')

plot_mass_coeff_en(energy=None, **kwargs)[source]¶

Plot the mass energy-absorption coefficient in the element

Creates a plot of the mass energy-absorption coefficient (in cm^2/g) as a function of photon energy in keV.

Parameters:

energyarray_like, optional: Energy grid on which to plot, replacing the default energy grid. Units are in keV.

Other Parameters:

**kwargs: Optional keyword arguments for plotting. See the plotting section of the curie API for a complete list of kwargs.

Examples

>>> el = ci.Element('Hf')

Example plotting the mass-attenuation coefficient together with the mass energy-absorption coefficient, on the same axes.

>>> f,ax = el.plot_mass_coeff(return_plot=True)
>>> el.plot_mass_coeff_en(f=f, ax=ax)

plot_range(particle='p', energy=None, density=None, **kwargs)[source]¶

Plot the charged particle range in the element

Creates a plot of the charged particle range (in cm) in the element as a function of the incident ion energy (in MeV).

Parameters:

particlestr: Incident ion. For light ions, options are ‘p’ (default), ‘d’, ‘t’, ‘a’ for proton, deuteron, triton and alpha, respectively. Additionally, heavy ions can be specified either by element or isotope, e.g. ‘Fe’, ‘40CA’, ‘U’, ‘Bi-209’.
energyarray_like, optional: Energy grid on which to plot, replacing the default energy grid. Units are in MeV.
densityfloat, optional: Density of the element in g/cm^3. Default behavior is to use Element.density.

Other Parameters:

**kwargs: Optional keyword arguments for plotting. See the plotting section of the curie API for a complete list of kwargs.

Examples

>>> el = ci.Element('Ar')
>>> el.plot_range()
>>> el.plot_range(density=0.5)

range(energy, particle='p', density=None)[source]¶

Charged particle range in matter

Calculates the charged particle range in the element, in cm. Incident energy should be in MeV, and the particle type definition is identical to Element.S().

Parameters:

energyarray_like: Incident ion energy in MeV.
particlestr, optional: Incident ion. For light ions, options are ‘p’ (default), ‘d’, ‘t’, ‘a’ for proton, deuteron, triton and alpha, respectively. Additionally, heavy ions can be specified either by element or isotope, e.g. ‘Fe’, ‘40CA’, ‘U’, ‘Bi-209’. For light ions, the charge state is assumed to be fully stripped. For heavy ions the charge state is handled by a Bohr/Northcliffe parameterization consistent with the Anderson-Ziegler formalism.
densityfloat, optional: Density of the element in g/cm^3. Default behavior is to use Element.density.

Returns:

rangenp.ndarray: Charged particle range in the element, in cm.

Examples

>>> el = ci.Element('Fe')
>>> print(el.range(60.0))
0.5858151125192633
>>> el = ci.Element('U')
>>> print(el.range(60.0))
0.3763111404628591

Element¶

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