Center for Ultrafast Optical Science, The University of Michigan, Ann Arbor, Michigan 48109, USA.
Phys Rev Lett. 2010 Jan 15;104(2):025004. doi: 10.1103/PhysRevLett.104.025004.
Experimental studies of electrons produced in a laser wakefield accelerator indicate trapping initiated by ionization of target gas atoms. Targets composed of helium and controlled amounts of various gases were found to increase the beam charge by as much as an order of magnitude compared to pure helium at the same electron density and decrease the beam divergence from 5.1+/-1.0 to 2.9+/-0.8 mrad. The measurements are supported by particle-in-cell modeling including ionization. This mechanism should allow generation of electron beams with lower emittance and higher charge than in preionized gas.
在激光尾流加速器中产生的电子的实验研究表明，通过目标气体原子的电离引发了捕获。与相同电子密度的纯氦相比，由氦和各种气体的受控量组成的目标发现可以将束电荷增加多达一个数量级，并将束发散度从 5.1+/-1.0 减小到 2.9+/-0.8 mrad。这些测量得到了包括电离在内的粒子模拟的支持。与预电离气体相比，这种机制应该可以产生具有更低发射度和更高电荷量的电子束。
