These cross sections were measured by the process of passing a deuteron beam into a thin gas target contained behind a thin window of evaporated silicon monoxide. The energy loss in the window was measured by a deceleration technique. Charged particles from the reactions were observed at 90° in the laboratory system with proportional counters. Some results are as follows: for the reaction D(d,p)T, by use of the angular distribution reported by Wenzel and Whaling, the total cross section o-is 15.4 mb with a probable error of 3.2 percent at 100-kev incident deuteron energy; cr=0.629 mb±5 percent at 25 kev. For the reaction D(d,n)JIe z , o-=15.2 mb±3.2 percent at 100 kev;
The n = 2 fine-structure transitions in positronium have been measured by observation of increased Lyman-a radiation at microwave induced resonances. We used an accelerator based slow positron beam to produce positronium in the 2 3 5'i excited state inside a waveguide. Our results are v 0 = 18499.65 ± 1.20±4.00 MHz, vi-13012.42±0.67±1.54 MHz, and v 2 =8 624.38 ±0.54 ± 1.40 MHz for the 2 3 S'i-* 2 3 Po,\,2 transition frequencies, respectively. The first error is statistical and the second is systematic. This is in agreement with recent bound state QED calculations.
The C2 fragmentation of fullerene ions C(q+)(60) (q = 1,2,3) induced by electron impact was studied for the first time. The cross sections for the loss of a C2 fragment indicate the presence of two different processes. At low electron energies the projectile electron leads to the direct excitation of the giant plasmon resonance. At electron energies larger than 100 eV the fragmentation of the fullerene ions can be described as an unsuccessful ionization. Only this second part of the cross section shows a dependence on the charge state q of the precursor ion.
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