Neutron Flux Calculator Formula
Understand the math behind the neutron flux calculator. Each variable explained with a worked example.
Formulas Used
Neutron Flux (phi)
flux = neutron_density * neutron_velocityReaction Rate Density
reaction_rate = neutron_density * neutron_velocity * cross_sectionVariables
| Variable | Description | Default |
|---|---|---|
neutron_density | Neutron Density (n)(n/cm³) | 100000000 |
neutron_velocity | Neutron Velocity (v)(cm/s) | 220000 |
cross_section | Macroscopic Cross Section (Sigma)(1/cm) | 0.1 |
How It Works
Neutron Flux and Reaction Rate
Neutron flux is a fundamental quantity in nuclear reactor physics. It determines the rate of nuclear reactions.
Formulas
phi = n × v (neutron flux)
R = phi × Sigma = n × v × Sigma (volumetric reaction rate)
where n is neutron density, v is neutron speed, and Sigma is the macroscopic cross section. Thermal neutron velocity at room temperature is about 2200 m/s.
Worked Example
A thermal reactor with n = 10⁸ n/cm³, v = 2.2 × 10⁵ cm/s, Sigma = 0.1 cm⁻¹.
neutron_density = 100000000neutron_velocity = 220000cross_section = 0.1
- 01phi = 10⁸ × 2.2 × 10⁵ = 2.2 × 10¹³ n/(cm²·s)
- 02R = 2.2 × 10¹³ × 0.1 = 2.2 × 10¹² reactions/(cm³·s)
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Open Neutron Flux Calculator