[1Ia01-07] Vacuum Science Technology (VST)

[1Ia04] Liquid nitrogen in-line trap for C₂H₅OH liquid target in an ultra-high vacuum

*Norio Ogiwara¹, Kazami Yamamoto², Masaya Kuramochi³ (1. J-PARC Center, High Energy Accelerator Research Organization , 2. J-PARC Center, Japan Atomic Energy Agency, 3. Total Support Systems Corporation)

An ultra-high vacuum compatible ethanol liquid target is being developed to investigate the reaction products produced by the interaction of a high intensity laser with ethanol. One of the issues to be solved is to maintain an ultra-high vacuum in the main chamber for analysis within ~1 m of the liquid target, where the the generator is planned to be operated about 10 Pa or less. The constraint is to have a straight-through section without obstructions for analysing the reaction products. In this development, this straight-through section is a cylinder with a diameter of 20 mm. The above problem was solved by installing an in-line liquid nitrogen trap between the reaction chamber and the main chamber and by improving the trap. It is experimentally shown that the ethanol vapor conductance between the reaction chamber and the trap decreased drastically by installing the cooling pipe. Also, if the same cooling pipes are installed not only between the trap and the reaction chamber, but also between the trap and the main chamber, and if the main chamber is evacuated with a pump of ~1 m³/s, you can almost certainly keep the main chamber in UHV.