Speaker
Description
The e$^{+}$BOOST (intense positron source Based On Oriented crySTals) project aims to demonstrate the effectiveness of a novel fixed-target positron source scheme enhanced by coherent phenomena in crystals. Future lepton colliders such as FCC-ee, CLIC, and CepC require unprecedented positron beam intensities to achieve their respective luminosity goals.
Conventional positron production schemes, based on a high-energy electron beam impinging on a solid target, are limited by the peak energy density deposition (PEDD) threshold, beyond which the target structure is compromised. A promising alternative is to exploit the intense coherent radiation emitted in oriented crystals, enabling a higher rate of $e^{+}e^{-}$ pair production compared to non-oriented targets, while significantly reducing the PEDD in the converter.
The proposed crystal-based positron source adopts a hybrid target configuration, consisting of a thin oriented crystal radiator followed downstream by a thicker amorphous converter, which transforms the generated photons into $e^{+}e^{-}$ pairs. This scheme, initially proposed in [1], has been successfully validated at CERN and KEK [2], and is currently under investigation within the FCC-ee injector design framework [3].
Recent experimental results have shown a clear enhancement in radiation yield when the crystal radiator is properly aligned with the incoming beam, as reported in [4] and [5], providing strong validation of the concept. These findings have also confirmed the reliability of the simulation framework [6], which is now being used to guide the optimization of a crystalline positron source for FCC-ee, as detailed in [7].
In this contribution, I will present the latest results of the e$^{+}$BOOST project, including both experimental outcomes and simulation studies supporting the development of future high-intensity positron sources.
[1] R. Chehab et al., DOI :10.5170/CERN-1989-005.105
[2] R. Chehab et al., DOI :10.1016/S0370-2693(01)01395-8
[3] I. Chaikovska et al., DOI: 10.18429/JACoW-IPAC2019-MOPMP003
[4] N.Canale et al., DOI : 10.1016/j.nima.2025.170342
[5] L.Bandiera et al., DOI : 10.1140/epjc/s10052-022-10666-6
[6] A. Sytov et al., DOI: 10.1007/s40042-023-00834-6
[7] F. Alharthi et al., DOI : 10.1016/j.nima.2025.170412
