No abstract

Antiprotonic X-rays from the helium isotopes have been observed at pressures of 36, 72, 375 and 600 mbar. The antiproton beam from LEAR with momenta of 309 and 202 MeV/c has been stopped at these pressures using the cyclotron trap. The X-rays were detected with Si(Li) and intrinsic Ge semiconductor detectors. Absolute Xray yields were determined and the strong-interaction 2p shifts and the 2p and 3 d broadenings measured to be Ezp=(-17_+4)eV, F2p=(25_+9)eV and Fad=(2.14 _+0.18)meV for /~3He and ezp=(-18+_2)eV, F2. =(45_+5) eV and Fad =(2.36 +0.10) meV for/54He.

X-rays of Balmer and Lyman transitions in antiprotonic hydrogen and of Balmer transitions in antiprotonic deuterium were observed at pressures below 300 hPa using Si(Li) semiconductor detectors. The measurement was performed at the LEAR-facility at a beam momentum of 202 MeV/c. In order to stop antiprotons in a low pressure gaseous target with high efficiency, a novel technique, the cyclotron trap has been used. Absolute yields were determined and compared with cascade calculations. A distinct difference in the cascade of antiprotonic hydrogen and deuterium is found. The parameters of strong interaction in antiprotonic hydrogen are determined to be 81~ = -(620 + 100)eV, Fls= (1130 _+ 170) eV and F2p = (32-t-10) meV.

The yields of the atomic 4--*3 transitions in antiprotonic 14N, 16'17'180, 19F, and 2aNa were measured at the CERN antiproton facility, LEAR. From these, the widths F~p of the 4f levels were determined to be 136_+19meV (14N); 603_+22meV (160); 731 _+35 meV (~vO); 795+23 meV (xso); 2.79_+0.16 eV (19F); and 23.8_+7.4 eV (23Na).