Author/Authors :
Bielert، نويسنده , , Katharina E. and Bremer-Streck، نويسنده , , J. and Doshita، نويسنده , , N. and Geyer، نويسنده , , Melissa R. and Hashimoto، نويسنده , , R. and Horikawa، نويسنده , , N. and Ishimoto، نويسنده , , S. and Iwata، نويسنده , , T. and Kondo، نويسنده , , K. and Mallot، نويسنده , , G.K. and Matsuda، نويسنده , , H. and Matsuda، نويسنده , , T. and Miyachi، نويسنده , , Y. and Nukazuka، نويسنده , , G. and Pirotte، نويسنده , , O. and Suzuki، نويسنده , , H. and Suzuki، نويسنده , , S. and Vullierme، نويسنده , , B.، نويسنده ,
Abstract :
A 2.5 m long liquid hydrogen target has been developed for the COMPASS experiment at CERN to investigate the nucleon spin structure via the Deeply Virtual Compton Scattering (DVCS) process. To recognize exclusive DVCS events, produced photons and slow protons need to be detected. In order to do so, the material budget around the target has to be minimal. A 0.125 mm thick Kapton ® target cell and a 1 mm thick carbon fiber vacuum chamber with a Mylar ® window have been constructed and tested. Finally, the target system was successfully employed during the DVCS pilot run in COMPASS at the end of 2012. The objective of this paper is to give a detailed description of this newly developed liquid hydrogen target apparatus.
