def test_angles_beam90_reacazi0(self):
for azi in numpy.linspace(0, 2*pi, 100):
proj = pytpc.Particle(4, 2, 2, polar=pi/2, azimuth=azi)
ejec, recoil = rel.elastic_scatter(proj, self.target, pi/2, 0)
self.assertAlmostEqual(ejec.azimuth, azi, places=3)
self.assertAlmostEqual(recoil.azimuth, azi, places=3)
self.assertAlmostEqual(abs(ejec.polar - recoil.polar), pi/2, places=2)
def test_azimuth(self):
for azi in numpy.linspace(0, 2*pi, 20):
ejec, recoil = rel.elastic_scatter(self.proj, self.target, self.cm_angle, azi)
self.assertAlmostEqual(ejec.azimuth, azi)
self.assertAlmostEqual(recoil.azimuth, constrain_angle(azi + pi))
def test_polar(self):
for cm_angle in numpy.linspace(0.01, pi, 20, endpoint=False):
ejec, recoil = rel.elastic_scatter(self.proj, self.target, cm_angle, self.azi)
self.assertAlmostEqual(ejec.polar + recoil.polar, pi/2, delta=2.0)
def test_energy(self):
ejec, recoil = rel.elastic_scatter(self.proj, self.target, self.cm_angle, self.azi)
self.assertAlmostEqual(recoil.energy, 0, places=4)
self.assertAlmostEqual(ejec.energy, self.proj.energy, places=4)
def test_energy_large_angle(self):
ejec, recoil = rel.elastic_scatter(self.proj, self.target, pi-0.01, self.azi)
self.assertAlmostEqual(ejec.energy, 0, places=3)
def test_energy_equal(self):
ejec, recoil = rel.elastic_scatter(self.proj, self.target, pi/2, self.azi)
self.assertAlmostEqual(recoil.energy, ejec.energy)
def simulate_elastic_scattering_track(proj, target, gas, ef, bf, interact_energy, cm_angle, azimuth):
"""Simulate an elastic scattering event with the given particles and parameters.
The projectile will be tracked in the detector until it has total energy equal to `interact_energy`. Then, an
elastic scattering interaction will happen with the provided COM angle and final azimuthal angle.
Parameters
----------
proj : Particle
The projectile. It must have non-zero energy.
target : Particle
The target. It must have zero energy (at least for now)
gas : pytpc.gases.Gas or subclass
The gas in the detector. If it's a subclass, make sure it is compatible with both the target and the
projectile.
ef : array-like
The electric field, in SI units
bf : array-like
The magnetic field, in Tesla
interact_energy : number
The energy at which to stop tracking the projectile and perform the interaction
cm_angle : number
The center-of-momentum angle for the relativistic scattering calculation
azimuth : number
The final azimuthal angle of the ejectile particle
Returns
-------
pandas.DataFrame
The concatenated outputs of the `track` function for each particle
Raises
------
ValueError
If the projectile has zero energy
NotImplementedError
If the target has nonzero energy. In the future, the code could be changed to allow a moving target particle,
but it seems unnecessary for now.
See Also
--------
pytpc.relativity.elastic_scatter
"""
if proj.energy == 0:
raise ValueError('Projectile must have energy > 0')
if target.energy > 0.0:
raise NotImplementedError('Target energy must be zero (for now at least)')
# Track projectile until the collision
proj_track = track(proj, gas, ef, bf, interact_energy)
if not(0 <= proj.position[2] <= 1) or sqrt(proj.position[0]**2 + proj.position[1]**2) > 0.275:
# The particle left the chamber before interacting
return proj_track
reaction_time = proj_track.time.max()
ejec, recoil = rel.elastic_scatter(proj, target, cm_angle, azimuth)
ejec_track = track(ejec, gas, ef, bf)
ejec_track.time += reaction_time
recoil_track = track(recoil, gas, ef, bf)
recoil_track.time += reaction_time
return pd.concat((proj_track, ejec_track, recoil_track), ignore_index=True)
