TestLinearCompton.cpp File Reference

Unit tests for the unpolarized linear Compton helper. More...

#include "Physics/LinearCompton.h"
#include "Physics/Physics.h"
#include "Utilities/Options.h"
#include "gtest/gtest.h"
#include <cmath>

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Functions
	TEST (TestLinearCompton, ThomsonLimitRecoveredAtLowEnergy)
	TEST (TestLinearCompton, EnergySupportMatchesComptonEndpoints)
	TEST (TestLinearCompton, DifferentialSpectrumIntegratesToTotalCrossSection)
	TEST (TestLinearCompton, NinetyDegreeLabForwardBenchmarkMatchesExactFormula)
	TEST (TestLinearCompton, ExplicitLabPhotonEnergyMatchesForwardHelper)
	TEST (TestLinearCompton, SampledEventsRespectKinematicBounds)
	TEST (TestLinearCompton, FixedSeedProducesDeterministicSampleSequence)

Detailed Description

Unit tests for the unpolarized linear Compton helper.

The implemented helper is intentionally limited to single-electron, unpolarized Klein-Nishina physics. The tests below validate four things:

Test:

TestLinearCompton::ThomsonLimitRecoveredAtLowEnergy Verifies that the exact Klein-Nishina total cross section approaches the Thomson limit for \(\omega_1 \ll m_e\).

Test:

TestLinearCompton::EnergySupportMatchesComptonEndpoints Verifies the exact electron-rest-frame energy support \(\omega_2 \in [\omega_1/(1+2\omega_1/m_e), \omega_1]\) and checks the recoil formula at the forward and backward endpoints.

Test:

TestLinearCompton::DifferentialSpectrumIntegratesToTotalCrossSection Numerically integrates \(d\sigma/d\omega_2\) over the exact support and compares it against the analytic Klein-Nishina total cross section.

Test:

TestLinearCompton::NinetyDegreeLabForwardBenchmarkMatchesExactFormula Reproduces the same 90 degree crossing benchmark used by the laser element: a 1 GeV electron moving along \(+\hat z\) and a 1030 nm laser propagating along \(+\hat x\). The forward scattered photon energy is compared against the exact stable laboratory-frame formula

\[ \omega_\gamma' = \frac{E_e \omega_L}{\omega_L + m_e^2 / (E_e + p_e)}. \]

Definition in file TestLinearCompton.cpp.

Function Documentation

TEST() [1/7]

TEST	(	TestLinearCompton	,
		DifferentialSpectrumIntegratesToTotalCrossSection
	)

Definition at line 85 of file TestLinearCompton.cpp.

References Physics::LinearCompton::scatteredPhotonEnergyMaxERFGeV(), Physics::LinearCompton::scatteredPhotonEnergyMinERFGeV(), and Physics::LinearCompton::totalCrossSection().

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TEST() [2/7]

TEST	(	TestLinearCompton	,
		EnergySupportMatchesComptonEndpoints
	)

Definition at line 68 of file TestLinearCompton.cpp.

References Physics::LinearCompton::scatteredPhotonEnergyERFGeV(), Physics::LinearCompton::scatteredPhotonEnergyMaxERFGeV(), and Physics::LinearCompton::scatteredPhotonEnergyMinERFGeV().

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TEST() [3/7]

TEST	(	TestLinearCompton	,
		ExplicitLabPhotonEnergyMatchesForwardHelper
	)

Definition at line 129 of file TestLinearCompton.cpp.

References Physics::LinearCompton::labForwardPhotonEnergyGeV(), Physics::LinearCompton::labPhotonEnergyGeV(), Physics::LinearCompton::photonEnergyFromWavelengthGeV(), and Physics::LinearCompton::restFrameScatteringCosineForLabForwardPhoton().

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TEST() [4/7]

TEST	(	TestLinearCompton	,
		FixedSeedProducesDeterministicSampleSequence
	)

Definition at line 191 of file TestLinearCompton.cpp.

References Physics::LinearCompton::makeHostRandomEngine(), Physics::LinearCompton::makeSamplingKernel(), Physics::LinearCompton::photonEnergyFromWavelengthGeV(), Physics::LinearCompton::sampleEvent(), and Options::seed.

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TEST() [5/7]

TEST	(	TestLinearCompton	,
		NinetyDegreeLabForwardBenchmarkMatchesExactFormula
	)

Definition at line 98 of file TestLinearCompton.cpp.

References Physics::LinearCompton::invariantX(), Physics::LinearCompton::labForwardPhotonEnergyGeV(), Physics::m_e, and Physics::LinearCompton::photonEnergyFromWavelengthGeV().

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TEST() [6/7]

TEST	(	TestLinearCompton	,
		SampledEventsRespectKinematicBounds
	)

Definition at line 153 of file TestLinearCompton.cpp.

References dot(), Physics::LinearCompton::makeHostRandomEngine(), Physics::LinearCompton::makeSamplingKernel(), Physics::LinearCompton::photonEnergyFromWavelengthGeV(), Physics::LinearCompton::sampleEvent(), Physics::LinearCompton::scatteredPhotonEnergyMaxERFGeV(), Physics::LinearCompton::scatteredPhotonEnergyMinERFGeV(), Options::seed, and Physics::two_pi.

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TEST() [7/7]

TEST	(	TestLinearCompton	,
		ThomsonLimitRecoveredAtLowEnergy
	)

Definition at line 60 of file TestLinearCompton.cpp.

References Physics::LinearCompton::thomsonCrossSection(), and Physics::LinearCompton::totalCrossSection().

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