Proposal for Using DAΦNE as Pulse Stretcher for the Linac Positron Beam

Susanna Guiducci, David Alesini, Maria Biagini, Shalva Bilanishvili, Oscar Blanco-García, Manuela Boscolo, Bruno Buonomo, Sergio Cantarella, Claudio Di Giulio, Luca Gennaro Foggetta, Alessandro Gallo, Andrea Ghigo (+10 others)
The PADME experiment* proposes a search for the dark photon (A') in the e⁺e⁻ -> gamma A' process in a positron-on-target experiment, exploiting the positron beam of the DAΦNE linac at the Frascati National Laboratory. The linac could provide a number of positrons as high as 10⁹/pulse in a 200 ns pulse but the number of positrons for PADME is limited below 10⁵/pulse in order to keep the pile-up probability in the calorimeter low enough. The PADME experiment is indeed limited by the low duty
more » ... y the low duty factor (10e-5=200ns/20ms). An alternative proposal to use the DAΦNE positron ring as a linac pulse stretcher, by injecting each pulse into the ring and extracting it by a slow resonant extraction using the m/3 resonance, is described in this paper. This allows to distribute the positrons of a linac pulse in a much longer pulse (0.2 - 0.5 ms) increasing the duty factor up to ~ 2%. The required modifications of the DAΦNE positron transfer line and main ring are presented. A dedicate lattice for the ring has been designed and tracking of the positrons in the ring has been performed to optimize extraction parameters and give a preliminary estimate of the extracted beam characteristics.
doi:10.18429/jacow-ipac2018-thpak023 fatcat:kuu33dajbjasvcpogr7go4hphy