LinearCompton.h File Reference

#include "OPALTypes.h"
#include <cstdint>
#include <random>

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Classes
struct	Physics::LinearCompton::SamplingKernel
	Host-only cached data for repeated linear-Compton event sampling. More...
struct	Physics::LinearCompton::SampledEvent
	Sampled single-photon Compton event. More...

Namespaces
namespace	Physics
namespace	Physics::LinearCompton

Functions
double	Physics::LinearCompton::photonEnergyFromWavelengthGeV (double wavelength_m)
	Convert a laser wavelength to a single-photon energy.
double	Physics::LinearCompton::electronGamma (double electronTotalEnergyGeV)
	Compute the electron Lorentz factor from total energy.
double	Physics::LinearCompton::electronBeta (double electronTotalEnergyGeV)
	Compute the electron speed in units of c from total energy.
double	Physics::LinearCompton::restFrameIncomingPhotonEnergyGeV (double electronTotalEnergyGeV, double laserPhotonEnergyGeV, const Vector_t< double, 3 > &beamDirection, const Vector_t< double, 3 > &laserDirection)
	Compute the incoming photon energy in the electron rest frame.
double	Physics::LinearCompton::invariantKappa (double incomingPhotonEnergyERFGeV)
	Compute the dimensionless Klein-Nishina parameter \(\\kappa = \\omega_1/m_e\).
double	Physics::LinearCompton::invariantX (double incomingPhotonEnergyERFGeV)
	Compute CAIN's linear-Compton invariant \(x = 2 \\omega_1 / m_e\).
double	Physics::LinearCompton::invariantX (double electronTotalEnergyGeV, double laserPhotonEnergyGeV, const Vector_t< double, 3 > &beamDirection, const Vector_t< double, 3 > &laserDirection)
	Compute CAIN's linear-Compton invariant directly from laboratory quantities.
double	Physics::LinearCompton::scatteredPhotonEnergyMinERFGeV (double incomingPhotonEnergyERFGeV)
	Minimum scattered photon energy in the electron rest frame.
double	Physics::LinearCompton::scatteredPhotonEnergyMaxERFGeV (double incomingPhotonEnergyERFGeV)
	Maximum scattered photon energy in the electron rest frame.
double	Physics::LinearCompton::scatteredPhotonEnergyERFGeV (double incomingPhotonEnergyERFGeV, double scatteringCosineERF)
	Compute the scattered photon energy in the electron rest frame.
double	Physics::LinearCompton::differentialCrossSectionSolidAngleERF (double incomingPhotonEnergyERFGeV, double scatteringCosineERF)
	Unpolarized Klein-Nishina differential cross section in solid angle.
Vector_t< double, 3 >	Physics::LinearCompton::restFrameIncomingPhotonDirection (double electronTotalEnergyGeV, const Vector_t< double, 3 > &beamDirection, const Vector_t< double, 3 > &laserDirection)
	Incoming laser-photon direction in the electron rest frame.
Vector_t< double, 3 >	Physics::LinearCompton::labPhotonDirection (double electronTotalEnergyGeV, const Vector_t< double, 3 > &beamDirection, const Vector_t< double, 3 > &laserDirection, double scatteringCosineERF, double azimuthERF)
	Laboratory-frame photon direction from electron-rest-frame scattering angles.
double	Physics::LinearCompton::labPhotonEnergyGeV (double electronTotalEnergyGeV, double laserPhotonEnergyGeV, const Vector_t< double, 3 > &beamDirection, const Vector_t< double, 3 > &laserDirection, double scatteringCosineERF, double azimuthERF)
	Laboratory-frame photon energy from electron-rest-frame scattering angles.
double	Physics::LinearCompton::differentialCrossSectionOmegaERF (double incomingPhotonEnergyERFGeV, double scatteredPhotonEnergyERFGeV)
	Unpolarized Klein-Nishina differential cross section in the scattered-photon energy.
double	Physics::LinearCompton::totalCrossSection (double incomingPhotonEnergyERFGeV)
	Total unpolarized Klein-Nishina cross section.
double	Physics::LinearCompton::thomsonCrossSection ()
	Thomson limit cross section.
double	Physics::LinearCompton::restFrameScatteringCosineForLabForwardPhoton (double electronTotalEnergyGeV, const Vector_t< double, 3 > &beamDirection, const Vector_t< double, 3 > &laserDirection)
	Rest-frame scattering cosine corresponding to a lab-forward photon.
double	Physics::LinearCompton::labForwardPhotonEnergyGeV (double electronTotalEnergyGeV, double laserPhotonEnergyGeV, const Vector_t< double, 3 > &beamDirection, const Vector_t< double, 3 > &laserDirection)
	Forward scattered photon energy in the laboratory frame.
std::mt19937_64	Physics::LinearCompton::makeHostRandomEngine (std::uint64_t streamIndex=0)
	Create a deterministic host-side random engine for Monte Carlo validation.
SamplingKernel	Physics::LinearCompton::makeSamplingKernel (double electronTotalEnergyGeV, double laserPhotonEnergyGeV, const Vector_t< double, 3 > &beamDirection, const Vector_t< double, 3 > &laserDirection)
	Build a cached sampling kernel for repeated event generation.
SampledEvent	Physics::LinearCompton::sampleEvent (const SamplingKernel &kernel, std::mt19937_64 &engine)
	Sample one unpolarized linear-Compton event on the host.

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Class Documentation

Physics::LinearCompton::SamplingKernel

struct Physics::LinearCompton::SamplingKernel

Host-only cached data for repeated linear-Compton event sampling.

The first Monte Carlo validation path in OPALX is intentionally scalar and host-side. This structure caches the fixed beam / laser geometry, the incoming photon energy in the electron rest frame, and the rejection-sampler envelope used to sample \(\cos\Theta^*\) from the unpolarized Klein-Nishina kernel.

The kernel is designed for deterministic testing and validation: create it once for a fixed benchmark geometry, seed a host RNG from Options::seed, and then draw sampled events via sampleEvent.

Definition at line 25 of file LinearCompton.h.

Collaboration diagram for Physics::LinearCompton::SamplingKernel:

Class Members
Vector_t< double, 3 >	beamDirection	Normalized incoming electron direction in the lab frame.
double	electronTotalEnergyGeV	Incoming electron total energy in the lab frame [GeV].
double	incomingPhotonEnergyERFGeV	Laser-photon energy after Lorentz transforming into the electron rest frame [GeV].
Vector_t< double, 3 >	laserDirection	Normalized incoming laser direction in the lab frame.
double	laserPhotonEnergyGeV	Incoming laser-photon energy in the lab frame [GeV].
double	rejectionUpperBoundSolidAngleERF	Conservative upper envelope for \(d\sigma/d\Omega^*\) used by the rejection sampler.

Physics::LinearCompton::SampledEvent

struct Physics::LinearCompton::SampledEvent

Sampled single-photon Compton event.

The event is parameterized by the electron-rest-frame scattering variables \((\cos\Theta^*, \phi^*)\) and the corresponding scattered photon energy and direction after boosting back to the laboratory frame.

Definition at line 49 of file LinearCompton.h.

Collaboration diagram for Physics::LinearCompton::SampledEvent:

Class Members
double	azimuthERF = 0.0	Rest-frame azimuth \(\phi^*\) around the incoming-photon axis [rad].
Vector_t< double, 3 >	scatteredPhotonDirectionLab	Normalized outgoing photon direction in the laboratory frame.
double	scatteredPhotonEnergyERFGeV	Outgoing photon energy in the electron rest frame [GeV].
double	scatteredPhotonEnergyLabGeV	Outgoing photon energy in the laboratory frame [GeV].
double	scatteringCosineERF	Rest-frame polar scattering cosine \(\cos\Theta^*\).