Production and Collections of Antiprotons

The historical best antiproton yield obtained at the antiproton source is equal to 1.8 · 10-5. That corresponds to the acceptance of about 17 mm · mrad while the largest measured debuncher acceptance is about 25 mm · mrad. It is expected that better debuncher tuning will increase the debuncher acceptance to about 35 mm · mrad. Thus, improvements of optics and steering in the AP2 line and debuncher should allow an increase of antiproton yield by about 1.7 times to 3.1 · 10-5 for 35 mm · mrad acceptance as shown in Figure 17. Although the maximum lithium lens gradient, which we can reliably achieve nowadays, is significantly below the optimum we should not expect significant increase of antiproton yield with lens upgrade. To reach the maximum antiproton yield with lens of the same length (15 cm) one would need to increase the lens gradient by 1.4 and 1.7 times correspondingly for 25 and 35 mm · mrad acceptances. That corresponds to gradients of 105 and 127 kG/cm reaching of which is a challenging problem. And in spite of this significant increase of focusing strength that will bring only 13% and 16% antiproton yield increases corresponding to acceptances of 25 and 35 mm · mrad. Minor improvement of about 3-4% can be achieved comparatively easy by lengthening of the lens by 20-30%.