The SLAC high-density gaseous polarized 3He target

Abstract

A large-scale high-pressure gaseous 3 He polarized target has been developed for use with a high-intensity polarized electron beam at the Stanford Linear Accelerator Center.This target was used successfully in an experiment to study the spin structure of the neutron. The target provided an areal density of about 7×10 21 nuclei/cm 2 and operated at 3 He polarizations between about 30% and 40% for the six-week duration of the experiment.

Optically polarizedHe3

“…With the notable exception of the early SLAC 5 3 He targets that used up to six Ti:Sapphire lasers (Johnson et al , 1995), these large, expensive and often unreliable sources were generally limited to <10 W of pumping light. The first application to SEOP with diode lasers was performed with relatively low power individual diodes (Wagshul and Chupp, 1989).…”

“…Using a few watts of laser light from a Tisapphire laser, an ≈50 cm 3 cell was polarized up to 40 % in tests and was maintained between 10 % and 27 % during the experiment. Double cell targets were then applied for deep inelastic scattering experiments (Johnson et al , 1995) with ≈25 GeV energy electrons at SLAC for the first studies of the neutron’s spin structure functions (Anthony et al , 1993, 1996). In this experiment, 3 He polarization between 30 % and 40 % was maintained in a 9 bar, 200 cm 3 double cell with 20 W of laser light from five Ti-sapphire lasers, each pumped with a 20W argon-ion laser (Johnson et al , 1995).…”

Polarized nuclear target based on parahydrogen induced polarization

“…3. Polarized-target experiments with up to 32 GeV electron beams at the Stanford Linear Accelerator Center (SLAC) [21][22][23], which used a 3 He target [24] with P n % 0:3, effective dilution D % 0:125, L % 3 Â 10 36 Hz=cm 2 , and NH 3 /LiD targets [25] with P p % 0:9, D % 0:16, and L % 7 Â 10 35 Hz=cm 2 for studies of inclusive deep inelastic scattering. 4.…”

A measurement of the absolute neutron beam polarization produced by an optically pumped neutron spin filter

“…Both techniques have been applied at the ILL in Grenoble and at NIST to polarize neutron beams [27][28][29]. The Rb spin exchange method has been used to produce polarized 3 He targets for several particle and nuclear physics experiments [31][32][33][34]. The first experiment using a 3 He spin filter to polarize an epithermal neutron beam was performed at Los Alamos by Coulter et al in 1989 [35].…”