EXPERIMENTS ON CHARGE-CHANGING COLLISIONS OF LITHIUM IONIC AND ATOMIC BEAMS
Beams of Li/sup +/ ions accelerated to kinetic energies in the range 10 to 475 kev were brought into charge equilibrium in the gases H/sub 2/, He, and N/ sub 2/ and the fractional amounts of Li/sup -/, Li/sup 0/, Li/sup +/, Li/sup +2/, and Li/sup +3/ measured. Because of the r elatively large amount of Li/sup -/ in an equilibrated beam below 40 kev in energy in propane and nitrous oxide, limited investigations were carried out in these gases. The anomalously large Li/sup +2/ yield in helium at Li/sup 7/ energies below 100 kev was noted. By holding each separated charged constituent successively in an orbit in a magnetic field, admitting gas. and observing the bcam attenuation, the total cross section for all charge-changing collisions was observed. Through application of the differential equations for growth or decay of a charged component, certian individual charge-changing cross sections can be deduced from these observed sums. Values are given for ( sigma /sup -//sub 10/ + sigma /sup -//sub 11/), sigma / sub 01/, sigma /sub 10/, sigma /sub 12/, sigma /sub 21/, and ( sigma /sub 32/ + sigma /sub 31/) in H/sub 2/, He, and N/sub 2/ target gases throughout the energy range. Upper limits can be assigned to sigma /sup -//sub 01/ sigma /sup -//sub 11/, sigma /sub 13/. and sigma /sub 23/. Use of data on ss/sup -//sub 11/ in H/ sub 2/ from other sources provides values of sigma /sup -//sub 01/ in that gas. Values for sigma /sub 21/ for Li/sup +2/ in helium gas, compared at common velocities with sigma /sub 10/ for He/sup +/ in helium and sigma /sup -//sub 01/ for H/sup 0/ in helium , show the exchange nature of the He/sup +/He interaction compared to that of the other isoelectronic structures. (auth) and DELTA nu (T) = 1516.701396 plus or minus 0.000030 Mc/sec. These results are based on a value of the hyperfine splitting of Cs/sup 133/ which is taken to be DELTA nu (Cs/sup 133/) = 9192.631840 Mc/sec. These measurements were made in various buffer gases that caused a shift in the observed hyperfine splitting, and the results given represent extrapolations to zero pressure. The pressure shifts were measured for hydrogen in argon, neon, helium, and molecular hydrogen and were measured for deuterium and tritium in argon and neon. The assigned limits of error represent the range of disagreement of the zero-pressure extrapolations in the differert buffer gases. (auth)
- Research Organization:
- Univ. of Chicago
- NSA Number:
- NSA-15-003275
- OSTI ID:
- 4111279
- Journal Information:
- Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D, Vol. Vol: 120; Other Information: Orig. Receipt Date: 31-DEC-61
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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