Steering and radiation effects in oriented crystals and their applications implementation into Geant4

Project Information

TRILLION

Grant agreement ID: 101032975

DOI

10.3030/101032975

Project closed

EC signature date 8 April 2021

Start date 2 September 2021

End date 30 January 2025

Funded under

• EXCELLENT SCIENCE - Marie Skłodowska-Curie Actions

Total cost

€ 249 465,36

EU contribution

€ 249 465,36

Coordinated by

ISTITUTO NAZIONALE DI FISICA NUCLEARE
Italy

Periodic Reporting for period 2 - TRILLION (Steering and radiation effects in oriented crystals and their applications implementation into Geant4)

Reporting period: 2023-09-02 to 2024-09-01

Summary of the context and overall objectives of the project

Crystals provide unique physical conditions for various electromagnetic effects involving both high-energy charged particles and photons. A small piece of crystal material could be used as an intense source of X- and gamma-ray radiation, a source of positrons, a beam manipulation instrument, a compact detector and a compact wake-field accelerator as well. Consequently, a crystal could be useful for a wide range of applications in accelerator physics, high-energy frontier physics, nuclear physics, cosmic-ray detectors, dark matter search and radiation therapy.

In particular, this will help to construct the future lepton colliders – multi-billion euro discovery machines opening new horizons in investigation of the fundamental laws of the Universe. It will provide a simple, low-cost and efficient tool of beam manipulation at tens of existing electron synchrotrons, which will considerably speed-up generic detectors R&D and will make available novel very high-energy fixed target experiments at future collider machines as well. In addition, the crystal X- and gamma- radiation source opens up the new perspectives in nuclear spectroscopy, nuclear transmutation and cancer radiation therapy.

The only way to design any application of a crystal is to perform complicated simulations usually requiring High Performance Computing on a supercomputer. The bottleneck is unification of rather marginal crystalline effects simulation codes with big physics packages such as Geant4 widely used for experimental setup design. The implementation of both physics of electromagnetic processes in oriented crystals and the design of specific applications of crystalline effects into Geant4 simulation toolkit as Geant4 examples to bring them to a large scientific and industrial community and under a free Geant4 license is the main objective of this Project.

As the main results, this physics was officially implemented into Geant4 within Geant4 Channeling Fast Simulation Model (G4ChannelingFastSimModel).

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

The G4ChannelingFastSimModel [1] to simulate charged particle trajectories as well as the radiation process was implemented into Geant4 and is officially available for download starting from Geant4-11.2.0 (release of December 8, 2023 https://geant4.web.cern.ch/download/11.2.0.html ). The model can be found in source/parameterisations/channeling/ . The updates of this model were realized within Geant4-11.3.0 (release of December 6, 2024 https://geant4.web.cern.ch/download/11.3.0.html).
Its brief description is released in Geant4 Physics Reference Manual https://geant4-userdoc.web.cern.ch/UsersGuides/PhysicsReferenceManual/html/solidstate/channeling/channeling_fastsim.html. The validation of every aspect of this simulation model with various experimental data was carried out.

This model represents itself as a full collection of physics of electromagnetic effects in oriented crystals necessary for simulations of all the main applications considered in the project:
crystal-based positron source for future electron-positron colliders, crystal-based extraction from an accelerator, and innovative X- and gamma- radiation source - crystalline undulator.
These applications were realized as Geant4 examples. The crystal-based extraction application is based on BDSim toolkit, which is designed for simulating beam dynamics in accelerators, while leveraging Geant4 as a library.

These results are being used by various collaborations, particular by IJCLab to develop FCC-ee positron source and by DESY for crystal-based extraction of electrons as well as by various INFN groups to simulate particle dynamics, radiation and electron-positron pair production for various applications, such as gamma radiation source and ultrashort crystalline calorimeter.

Many new collaborations have been started in other possible applications of oriented crystals, in particular in plasma wakefield acceleration in crystals and nanostructures, ultra-compact crystalline calorimeter, in particular for gamma-ray space telescope, dark matter search and Machine Learning for faster simulations.

The work was presented in 19 invited talks, 33 oral and 11 poster presentations and was published in 21 papers.

1. A. Sytov et al. Journal of the Korean Physical Society 83, 132-139, (2023). DOI: https://doi.org/10.1007/s40042-023-00834-6 arXiv:2303.04385

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

The model already implemented into Geant4 from the start of this project, is a unique Geant4 model that allows one to simulate the interaction of electrons and positrons with oriented crystals. It provides very simple interface to a user, which needs to add just several lines of the code to activate the model. At the same time the model does not require any modification of a physics list, and, consequently, it can be used with standard simulation setups already developed by users.

Generally, the implementation into Geant4 of all the applications mentioned in this project makes the Geant4 toolkit a key to R&D and future exploitation of crystals as a beam manipulation instrument, radiation and positron source etc. at tens of accelerators and colliders around the world.

Applications of oriented crystals