Pulsed beam of extremely large helium droplets
Abstract
We generated a pulsed helium droplet beam with average droplet diameters of up to 2 μ m using a solenoid pulsed valve operated at temperatures as low as 7 K. The droplet diameter was controllable over two orders of magnitude, or six orders of the number of atoms per droplet, by lowering the valve temperature from 21 to 7 K. A sudden droplet size change attributed to the so-called ;supercritical expansion; was firstly observed in pulsed mode, which is necessary to obtain the micrometer-scale droplets. This beam source is beneficial for experiments that require extremely large helium droplets in intense, pulsed form.
- Publication:
-
Cryogenics
- Pub Date:
- December 2017
- DOI:
- 10.1016/j.cryogenics.2017.10.016
- Bibcode:
- 2017Cryo...88...78K
- Keywords:
-
- Helium droplet;
- Pulsed beam;
- Supersonic expansion;
- Nano-science