Proposal

Bugfixes

- Made correction factor non-relativistic electrons numerically stable at very low energies (PR [314](https://github.com/tudo-astroparticlephysics/PROPOSAL/pull/314))
- Add missing entry for `InteractionType::Photoeffect` (PR [312](https://github.com/tudo-astroparticlephysics/PROPOSAL/pull/312))

Miscellaneous

- Update ubuntu-18.04 runner to ubuntu-20.04 (PR [315](https://github.com/tudo-astroparticlephysics/PROPOSAL/pull/315))

Physics improvements

- Inclusion of the photoeffect as an interaction type for photons ([296](https://github.com/tudo-astroparticlephysics/PROPOSAL/pull/296))
- Adapt LowerEnergyLim of Compton ([307](https://github.com/tudo-astroparticlephysics/PROPOSAL/pull/307))
- Change KinematicLimits of BremsElectronScreening ([308](https://github.com/tudo-astroparticlephysics/PROPOSAL/pull/308))
Bugfixes

- HitGeometry unreliable with multiple scattering ([289](https://github.com/tudo-astroparticlephysics/PROPOSAL/pull/289))

Runtime improvements

- Avoiding unnecessary calculations in `CrossSectionDNDXInterpolant::Calculate` ([295](https://github.com/tudo-astroparticlephysics/PROPOSAL/pull/295))
- Add onedimensional rate interpolant ([298](https://github.com/tudo-astroparticlephysics/PROPOSAL/pull/298))

Miscellaneous

- Add secondaries documentation ([293](https://github.com/tudo-astroparticlephysics/PROPOSAL/pull/293))
- Update modules and fix CI ([294](https://github.com/tudo-astroparticlephysics/PROPOSAL/pull/294))
- Fix CI again ([304](https://github.com/tudo-astroparticlephysics/PROPOSAL/pull/304))
- Logging for table creation and change file extension of tables from .txt to .dat ([306](https://github.com/tudo-astroparticlephysics/PROPOSAL/pull/306))
- Fix typos in new logging messages ([310](https://github.com/tudo-astroparticlephysics/PROPOSAL/pull/310))
- Restructure `Bremsstrahlung::GetKinematicLimits`([309](https://github.com/tudo-astroparticlephysics/PROPOSAL/pull/309))

Functionality
- Add `InterpolationSettings::NODES_UTILITY` (PR [281](https://github.com/tudo-astroparticlephysics/PROPOSAL/pull/281))

Bugfixes

- Avoid continuous randomization below min_energy (PR [276](https://github.com/tudo-astroparticlephysics/PROPOSAL/pull/276))
- Catch negative dNdx values (PR [277](https://github.com/tudo-astroparticlephysics/PROPOSAL/pull/277))
- Fix accessed random number in NaivCompton::CalculateSecondaries (PR [279](https://github.com/tudo-astroparticlephysics/PROPOSAL/pull/279))
- Catch calculation that can become `nan` in `Highland::CalculateTheta0` (PR [282](https://github.com/tudo-astroparticlephysics/PROPOSAL/pull/282))
- Fix Secondaries calculation when Multiple Scattering is enabled (PR [278](https://github.com/tudo-astroparticlephysics/PROPOSAL/pull/278))
- Add missing clone function to HighlandIntegral (PR [285](https://github.com/tudo-astroparticlephysics/PROPOSAL/pull/285))
- error in bremsstrahlung deflection for low energies (PR [280](https://github.com/tudo-astroparticlephysics/PROPOSAL/pull/280))

Miscellaneous

- Avoid invalid uses of EnergyCutSettings for only stochastic parametrizations (PR [271](https://github.com/tudo-astroparticlephysics/PROPOSAL/pull/271))
- move Maximilian Sackel to former developers ( PR [275](https://github.com/tudo-astroparticlephysics/PROPOSAL/pull/275))

Physics improvements

- Add γ->µµ as a new interaction process (PR [265](https://github.com/tudo-astroparticlephysics/PROPOSAL/pull/265))
- Add deflection Van Ginneken as new parametrizations for stochastic muon deflections (PR [244](https://github.com/tudo-astroparticlephysics/PROPOSAL/pull/244))

Bugfixes

- Fix extrapolation to lower energies for PhotoproductionRhode (PR [260](https://github.com/tudo-astroparticlephysics/PROPOSAL/pull/260))
- Rewrite Propagator::AdvanceParticle method (PR [267](https://github.com/tudo-astroparticlephysics/PROPOSAL/pull/267))

Miscellaneous

- Fix windows CI (PR [261](https://github.com/tudo-astroparticlephysics/PROPOSAL/pull/261))
- Add init kwargs for Box and Cylinder (PR [264](https://github.com/tudo-astroparticlephysics/PROPOSAL/pull/264))
- Cylinder: change order of arguments in json documentation (PR [266](https://github.com/tudo-astroparticlephysics/PROPOSAL/pull/266))
- Add UnitTests for PhotoMuPairProduction (PR [269](https://github.com/tudo-astroparticlephysics/PROPOSAL/pull/269))

**Bugfixes**

- Fix linker error for specific build configurations (PR 258 )

**Physics improvements**

- Add Photoproduction (Gamma + Hadron interaction) as a new interaction type (PR 222)
- Restructure PhotoPairProduction secondary calculation classes, adding `PhotoPairProductionKochMotzForwardPeaked` as a new parametrization to describe PhotoPairProduction secondaries (PR 247)

**Functionality**

- Add variable `end_position` to ContinousLosses (PR 223)
- Add `target_hash` information to StochasticLoss objects to keep information about the medium/component that we interacted with; add `GetMediumForHash` and `GetComponentForHash` functions to get medium/component for a given hash (PR 224)
- Improve v node distribution for Ionization interpolation to increase accuracy of stochastic losses (PR 240)
- Add function `HitGeometry` to Secondaries (PR 241)
- Move density_correction parameter for LPM classes from Constructor to method (PR 243)

**Bugfixes**

- Register custom ParticleDef objects in Type_Particle_Map; momenta of custom particles are calculated correctly now (PR 225)
- Return empty Loss object in Interaction::SampleLoss if no stochastic interaction is possible, avoiding rare runtime errors during propagation (PR 230)
- Improve search for the correct python version for installations with pip (PR 234)
- add missing `NoScattering` case to make_multiple_scattering function (PR 245)
- New return case if UtilityInterpolant::GetUpperLimit is trivial, avoiding occasional numerical problems (PR 249)
- Avoid (possible) unnecessary recalculations when crossing sector borders, avoiding occasional numerical problems (PR 251)
- Fix wrong order in AdvanceDistance, fix to PR 251 (PR 252)
- Catch negative values of the differential crosssection for PhotoQ2Intgration (PR 256)

**Miscellaneous**

- Fix caches in GitHub actions (PR 228)
- Push GTest version to 1.11.0 (PR 232)
- Update setup.cfg (PR 235)
- Improve jupyter notebook example and update README.md (PR 236)
- Clarify exception thrown when path to configuration file is not readable (PR 237)
- Add Austin Schneider to author list (PR 239)
- UnitTest overhaul (PR 242)