Fig. 5: Antiproton annihilations observed by the SVD during various phases of the H̅ accumulation process.

Each plot looks at a specific time window during a synthesis cycle and shows the integration of detected annihilations in that time window over many synthesis cycles. Therefore, the total ‘time’ of each plot varies with the number of synthesis cycles that have been integrated. The red dashed lines indicate the axial extent of the magnetic-minimum trap where H̅ is accumulated. a Annihilations during a single experiment where 2835 H̅ were accumulated in 225 synthesis cycles. The time window includes SDR-EVC on e⁻ and the transfer of p̅ into the left trap region (Fig. 1). The peak at −19 cm (also visible in (c) and (d)) is p̅ annihilating on residual gas during their preparation in the left trap region. The smeared-out peak around −7 cm from 10 s to 19 s are H̅ annihilating due to e⁻ that were ejected to the right (i.e., into the H̅ trap region) during SDR-EVC on e⁻. This H̅ loss was removed by letting the SDR-EVC process spill e⁻ to the left (negative positions), away from the trapped H̅. b Annihilations during two separate experiments that together accumulated 9715 H̅ in 199 synthesis cycles. The 8 s window covers a ~ 0.5 s move of ~5 million Be⁺ from the left trap to the right trap, and we see a trail of H̅ annihilations during this movement. These losses were removed by moving the initial Be⁺ preparation from the right trap to the left trap such that only ~100k Be⁺ ions are ever present in the magnetic-minimum trap region. c Annihilations during one experiment that accumulated 9274 H̅ in 159 synthesis cycles. The losses occur while merging Be⁺ with e⁺. They were eliminated by merging them in the right trap outside the magnetic-minimum trap. d Annihilations during eight separate experiments that accumulated a sum total of 92779 H̅ in 1443 synthesis cycles. The H̅ losses (region 4–16 cm, 1—2 s) are due to the presence of recaptured e⁺ that are held briefly (for ~1 s) in the magnetic-minimum trap region until they cool into a potential well in the right trap.