Electron Range

The electron_range function calculates the maximum distance that electrons can travel in a material before losing all their energy. This calculation can be performed using various theoretical and empirical models.

Function Purpose

Calculate the maximum electron range in a material using different stopping power models. This is essential for:

Radiation therapy treatment planning
Shielding calculations
Detector design
Radiation protection

Input Parameters

input: The electron energy in MeV. The function accepts:
- A single value as float or int
- A numpy.ndarray of energy values
- A Python list of energy values
material (optional): The material through which the electrons travel. Can be specified as:
- An integer ID (e.g., 1 for water)
- A Material object
- Defaults to 1 (liquid water) See the Materials documentation for detailed information about available materials.
model (optional): The stopping power model to use. Can be specified as:
- A string name (e.g., "tabata")
- An integer ID (e.g., 7 for Tabata model)
- Defaults to "tabata"

Available Models

Model Name	ID	Description
`"butts_katz"`	2	Butts & Katz model, suitable for track structure calculations
`"waligorski"`	3	Waligorski model, optimized for radiobiology applications
`"geiss"`	4	Geiss model, focused on heavy ion interactions
`"scholz"`	5	Original Scholz model
`"edmund"`	6	Edmund model
`"tabata"`	7	Tabata model (default), widely used empirical model
`"scholz_new"`	8	Updated Scholz model with improved accuracy

Output

The function returns the calculated range(s) in meters as:

A float for a single input value
A numpy.ndarray for NumPy array input
A Python list for list input

Notes

The range values represent the maximum distance electrons can travel in the material
Different models may give varying results due to different theoretical approaches
Model variations typically stay within physically reasonable bounds
The function supports vectorized operations for efficient batch calculations
Results scale correctly with energy (higher energy = longer range)
All models work with all available materials

Example Usage

Basic Usage with Default Model

import pyamtrack

energy = 100.0  # MeV
range_m = pyamtrack.stopping.electron_range(energy)
print(f"Range in water: {range_m:.2e} m")

Using Different Materials

import pyamtrack
from pyamtrack import materials

energy = 100.0  # MeV

# Using material ID
range_water = pyamtrack.stopping.electron_range(
    energy, 
    material=1  # water
)

# Using Material object
range_air = pyamtrack.stopping.electron_range(
    energy,
    material=materials.air
)

print(f"Range in water: {range_water:.2e} m")
print(f"Range in air: {range_air:.2e} m")

Using Different Models

import pyamtrack

energy = 100.0  # MeV

# Using model name
range_tabata = pyamtrack.stopping.electron_range(
    energy,
    model="tabata"
)

# Using model ID
range_scholz = pyamtrack.stopping.electron_range(
    energy,
    model=5  # scholz model
)

print(f"Range (Tabata): {range_tabata:.2e} m")
print(f"Range (Scholz): {range_scholz:.2e} m")

Batch Calculations

import pyamtrack
import numpy as np

energies = np.array([10.0, 50.0, 100.0, 500.0])  # MeV
ranges = pyamtrack.stopping.electron_range(energies)
print(f"Ranges: {ranges}")

Error Handling

The function includes comprehensive error checking:

import pyamtrack

try:
    # Invalid material
    range_invalid = pyamtrack.stopping.electron_range(
        100.0,
        material="invalid"
    )
except TypeError as e:
    print(f"Material error: {e}")

try:
    # Invalid model
    range_invalid = pyamtrack.stopping.electron_range(
        100.0,
        model="invalid_model"
    )
except RuntimeError as e:
    print(f"Model error: {e}")

Function Purpose​

Input Parameters​

Available Models​

Output​

Notes​

Example Usage​

Basic Usage with Default Model​

Using Different Materials​

Using Different Models​

Batch Calculations​

Error Handling​

See Also​