Bright, continuous beams of cold free radicals
Bright, continuous beams of cold free radicals
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DOI：
10.1103/physreva.102.041302
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发表时间：
2020-08
影响因子：
2.9
通讯作者：
J. Shaw;D. McCarron
中科院分区：
文献类型：
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作者：
J. Shaw;D. McCarron
我们展示了一种低温缓冲气冷分子束源，能够通过激光烧蚀产生明亮的、连续的冷自由基和缓慢的自由基束，持续时间长达60秒。源的设计使用了一个封闭的液氦储层作为一个大的热质量，以最大限度地减少加热，并确保在操作过程中光束的可重复性。在典型条件下，源产生我们的测试物种SrF光束，在$X^{2}\Sigma(v=0, N=1)$状态下，每英尺每秒含有$5\times10^{12}~$分子，旋转温度为$1.0(2)~$ K，前进速度为$140~$ m/s。光束的特性是稳定的，对于多个细胞的几何形状是不变的，但主要取决于氦缓冲气体的流速，必须是$\geq10~$标准立方厘米每分钟，以产生明亮的，连续的分子光束，烧蚀重复率为$55~$赫兹。
We demonstrate a cryogenic buffer gas-cooled molecular beam source capable of producing bright, continuous beams of cold and slow free radicals via laser ablation over durations of up to 60~seconds. The source design uses a closed liquid helium reservoir as a large thermal mass to minimize heating and ensure reproducible beam properties during operation. Under typical conditions, the source produces beams of our test species SrF, containing $5\times10^{12}~$molecules per steradian per second in the $X^{2}\Sigma(v=0, N=1)$ state with a rotational temperature of $1.0(2)~$K and a forward velocity of $140~$m/s. The beam properties are robust and unchanged for multiple cell geometries but depend critically on the helium buffer gas flow rate, which must be $\geq10~$ standard cubic centimeters per minute to produce bright, continuous beams of molecules for an ablation repetition rate of $55~$Hz.