A Gas Target Internal to the LHC for the Study of pp Single-Spin Asymmetries and Heavy Ion Collisions

Table 1

Comparison of gas targets in storage rings with a hypothetical target for the proposed AFTER@LHC initiative [1, 2].The target gas ¹H, ²D, or ³He is assumed to be spin polarized.

Storage ring	Particle	GeV	Target type	m	K	1/cm^2 s	Remarks	Reference
HERA-e; DESY; (term. 2007)	e^±  pol.	27.6	Cell; ^1H, ^2D, ^3He	0.4	100; 25		HERMES exp.; 1995–2007	[9]
RHIC-p; BNL	p pol.	250	Jet	—	—		Absolute p polarimeter	[10]
COSY; FZ Jülich	p, d pol.	3.77; = 49.3 MeV	Cell  ^1H, ^2D; Cell ^1H	0.4	300	10^29	ANKE exp.; PAX exp.	[4, 5]; [11]
LHC; CERN; (proposed)	p unpol.; heavy ions	7,000	Cell; ^1H, ^2D; Xe	1.0	100; ≥100	10^33; 10^27–10^28	Based on techn. of HERMES target	this paper