The status of the first phase of LHCspin is discussed, based on an unpolarized gas target - SMOG2 -, an upgrade of the previous SMOG system. It consists of an openable 20 cm long storage tube in front of the VELO detector. A known gas flow from a gas feed system is injected into the tube's center, producing a localized triangular density distribution. First tests of the SMOG2 system with LHC beam and H2, He, Ne and Ar gas have been performed. The target system and the precision for setting the target areal density are presented. - In the second part, design considerations for a polarized gas target at the LHC are presented. The fact that the initial tests worked as expected is a strong confirmation that the storage cell/tube is a viable concept compatible with LHC conditions. For the beam stability, very few coatings of surfaces close to the LHC beam are accepted. The SMOG2 cell is coated with amorphous Carbon (a-C). It is an open question whether this coating might be used for a polarized target cell. In order to circumvent the coating problem, a free-beam PGT within the present VELO-vessel has been presented. This could be a reasonable starting point for a Spin program at the LHC.
LHCspin: Unpolarized gas target SMOG2, and prospects for a polarized gas target at the LHC
Steffens E.
;Carassiti V.;Ciullo G.;Lenisa P.;Pappalardo L. L.;Tagliente G.
2023
Abstract
The status of the first phase of LHCspin is discussed, based on an unpolarized gas target - SMOG2 -, an upgrade of the previous SMOG system. It consists of an openable 20 cm long storage tube in front of the VELO detector. A known gas flow from a gas feed system is injected into the tube's center, producing a localized triangular density distribution. First tests of the SMOG2 system with LHC beam and H2, He, Ne and Ar gas have been performed. The target system and the precision for setting the target areal density are presented. - In the second part, design considerations for a polarized gas target at the LHC are presented. The fact that the initial tests worked as expected is a strong confirmation that the storage cell/tube is a viable concept compatible with LHC conditions. For the beam stability, very few coatings of surfaces close to the LHC beam are accepted. The SMOG2 cell is coated with amorphous Carbon (a-C). It is an open question whether this coating might be used for a polarized target cell. In order to circumvent the coating problem, a free-beam PGT within the present VELO-vessel has been presented. This could be a reasonable starting point for a Spin program at the LHC.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
