catima/docs/pycatima.md

Usage

Installation

Easiest way is to install pycatima on Linux and Windows is using pip:

pip install pycatima

note: python 3.7-3.9 is required

Pojectile

Projectile is defined by pycatima.Projectile class. It is initialized using:

Projectile(A, Z, Q=Z, T=0)

where A is mass in u units, Z is proton number, Q is charge state and T is energy in Mev/u units.

import pycatima
p = pycatima.Projectile(238.00032 ,92)  # 238U92+ at 0 Mev/u 
p = pycatima.Projectile(238.00702 ,92,90,1000)  # 238U90+ at 1000 Mev/u 

# following methods are defined:
mass = p.A()  # get mass of the nucleus us u units
z = p.Z()  # get proton number
q = p.Q()  # get charge state
energy = p.T()  # get energy
p.T(1000)  # set energy

Material

Material is defined by pycatima.Material class. The recommended way of initialization is usign the following init signature:

Material(elements, density, thickness, i_potential, mass)

• elements - list of elements, where element is defined as list of [A, Z, STN] A is atomic mass of the element, if 0 natural abundance atomic mass is taken, Z is the proton number of the element, STN is the stoichiometric if >=1.0 or weight fraction if < 1.0
• density - optional, defaults to 0
• thickness - optional, if not defined 0
• i_potential - optional, if <=0 it will be calulated using Bragg rule from elemental ionization potentials
• mass - optional, if <=0 it will be calculated from elements masses and STN number.

Material class has following methods:

• add_element(a, z, stn) - adds another element to the material, see initialization comments for details about, a,z, stn
• ncomponents() - returns number of elements in the material
• density() - returns density
• density(value) - set density
• thickness() - get thickness in g/cm^2
• thickness(value) - set thickness in g/cm^2
• thickness_cm(value) - set thickness in cm
• I() - get mean ionization potential
• I(value) - set mean ionization potential

Default Materials

The material with predefined density and atomic weights can be obtained for elemental targets and some compounds using:

pycatima.get_material(id)

id is integer which identifies material, For elements use 1-99 for elemental targets and >200 for compounds. See available pre-defined compounds in predefined material section in manual./

Example

import pycatima

#H2O with natural atomic masses and Ipot=78eV
h2o = pycatima.Material([[0,1,2],[0,8,1]],density=1.0, i_potential=78)
h2o.thickness_cm(1.0) # 1cm of water
# C target
c_mat = pycatima.get_material(6)
c_mat.thickness(0.1) # set to 0.1g/cm2 

Layers

Layers are sequential layers of Material which Projectile passes. The pycatima.Layers class is defined using following signature: Layers() This creates empty layers which needs to be filled by Material class.

Layers clas has following methods:

• add(material) - add material to the layers, material must be Material class
• add_layers(other) - add all material from Layers class other
• num() - returns number of layers
• get_item(i) returns i-th Material class
• __get(i) returns i-th Material class

Example

import pycatima
layers = pycatima.Layers()

# define some materials
graphite = pycatima.get_material(6)
graphite.thickness(0.2)
p10 = pycatima.get_material(pycatima.material.P10)
p10.thickness_cm(2.0)
air = pycatima.get_material(pycatima.material.Air)
air.thickness_cm(2.0)

# now add materials to layers
layers.add(graphite)
layers.add(air)
graphite.thickness(0.1) # change thickness for next layer
layers.add(graphite)
layers.add(p10)

Calculation

Calculations are done using mainly via functions:

• calculate(Projectile, Material)
• calculate_layers(Projectile, Layers)

The calculate function returns Result class and calculate_layers returns MultiResult_class

Example

import pycatima
water = catima.get_material(catima.material.Water)
water.thickness(1.0)
p = catima.Projectile(1,1)
p.T(1000)  # set projectile energy to 1000MeV/u

res = catima.calculate(p,water) # now res contains results
d = res.get_dict() # get results as dictionary

p = catima.Projectile(12,6)
water = catima.get_material(catima.material.Water)
water.thickness(10.0)
graphite = catima.get_material(6)
graphite.thickness(1.0)
graphite.density(2.0)

mat = catima.Layers()
mat.add(water)
mat.add(graphite)

# now calculate results for projectile at 1000MeV/u
res = catima.calculate_layers(p(1000),mat)

Results

Results class stores results for 1 layer of Material. It has following variables:

• Ein - Energy at entrance of the material in MeV/u
• Eloss - Energy loss in material in MeV
• Eout - Energy at the end of material in MeV/i
• dEdxi - Stopping power at entrance
• dEdxo - Stopping power at exit
• range - range in the material in g/cm^2
• sigma_E - Energy straggling in MeV/u
• sigma_a - Angular straggling in rad
• sigma_r - range straggling in g/cm^2
• sigma_x - position straggling in cm
• sp - non-reaction probability
• tof - time of flight through the material

MultiResults class stores the results for multiple layers. It consists of following variables:

• total_result - Result class with total results for projectile passing all layers.
• results - list of Result classes, one for each layer in Layers

Config

TODO