Development of Solid Hydrogen Target for GeV Photon Experiments
Abstract
We have developed a solid hydrogen target system for GeV photon experiments at LNS, in particular for the H(γ,η)and D(γ,η) experiments. A GeV tagged photon beam collides with a target which is placed at a distance of 7.5 m from the radiator inside the electron synchrotron ring. The size of beam at the target position is about 2 cm in diameter. Thus, in order to proceed the experiments effectively, we need a target having a large volume, at least larger than 3 cm × 3 cm × 2 cm (height × width × length). Since the energy loss of the photon beam is very small, we have designed a solid hydrogen target system with a commercially available 4K-GM cryocooler. Our method to produce a ``frozen target'' is to convert gas directly into solid on the cooling stage of GM cryocooler. The target is produced in the acrylic airtight room on the cooling stage. After crystalization of hydrogen gas we can remove this acrylic part and the target become free standing state against photon beam. The solid hydrogen made in our method can last very long and the H(γ,η) experiment has been succesfully carried out for about 4 days.
- Publication:
-
APS Meeting Abstracts
- Pub Date:
- October 2001
- Bibcode:
- 2001APS..HAW.BG001N