Simple loss scaling laws for quadrupoles and higher-order multipoles used in antihydrogen traps

Critical loss radius in a Penning trap subject to multipole fields

“…Previously, we used PIC simulations 6 to show that, in this case, the effective trap length, L eff , is half the end-to-end bounce length L of the particles in the trap. 14 Here we show that this result is a consequence of constraints imposed by adiabatic invariants. In the second case, particles held in a short trap are injected into a longer trap, with a preexisting multipole field.…”

“…Whether the Penning traps will still function adequately with these extra fields has been controversial. [6][7][8][9][10][11][12][13][14][15] Three types of multipole fields have been proposed: Quadrupole fields 16,17 such that the field at the center of the trap ͑ignoring the mirrors at the ends͒ is given, in cylindrical coordinates ͑r , , z͒, by…”

Compression of Antiproton Clouds for Antihydrogen Trapping

“…To trap both charged and neutral species simultaneously, the Minimum-B and Penning-Malmberg traps must be colocated. The compatibility of Minimum-B and PenningMalmberg traps remains controversial [4,5,7], but it is clear that the two are most compatible if the p's and e + 's are held close to the trap axis where the perturbations from the Minimum-B trapping fields are smallest [8,9,10]. Furthermore, holding the p's and e + 's near the axis increases their overlap, and slows the E × B drifts of the p's.…”

“…We have demonstrated areal density increases by as much as a factor of ten, and have produced p clouds with radii as small as 0.29 mm. Clouds of this size are far from the loss limits [9] of our trap [4], and promise to be much easier to confine.…”

A novel antiproton radial diagnostic based on octupole induced ballistic loss

“…For a given end-to-end bounce length L, field lines lying outside of a critical radius r c at the trap center will hit the wall, while those lying inside the critical radius will not. The normalized critical radius is [21,22]:…”