  The precise measurement of stellar abundances plays a pivotal role in
providing constraints on the chemical evolution of the Galaxy. However, before
spectral lines can be employed as reliable abundance indicators, particularly
for challenging elements such as helium, they must undergo thorough scrutiny.
Galactic open clusters, representing well-defined single stellar populations,
offer an ideal setting for unfolding the information stored in the helium
spectral line feature. In this study, we characterize the profile and strength
of the helium transition at around 10830{\AA} (He 10830) in nine giant stars in
the Galactic open cluster Stock 2. To remove the influence of weak blending
lines near the helium feature, we calibrated their oscillator strengths ($\log
gf$) by employing corresponding abundances obtained from simultaneously
observed optical spectra. Our observations reveal that He 10830 in all the
targets is observed in absorption, with line strengths categorized into two
groups. Three stars exhibit strong absorption, including a discernible
secondary component, while the remaining stars exhibit weaker absorption. The
lines are in symmetry and align with or around their rest wavelengths,
suggesting a stable upper chromosphere without a significant systematic mass
motion. We found a correlation between He 10830 strength and Ca II
$\log{R'_\mathrm{HK}}$ index, with a slope similar to that reported in previous
studies on dwarf stars. This correlation underscores the necessity of
accounting for stellar chromosphere structure when employing He 10830 as a
probe for stellar helium abundance. The procedure of measuring the He 10830 we
developed in this study is applicable not only to other Galactic open clusters
but also to field stars, with the aim of mapping helium abundance across
various types of stars in the future.
