  In recent years, negative triangularity (NT) has emerged as a potential
high-confinement L-mode reactor solution. In this work, detachment is
investigated using core density ramps in lower single null Ohmic L-mode plasmas
across a wide range of upper, lower, and average triangularity (the mean of
upper and lower triangularity: $\delta$) in the TCV tokamak. It is universally
found that detachment is more difficult to access for NT shaping. The outer
divertor leg of discharges with $\delta\approx -0.3$ could not be cooled to
below $5~\mathrm{eV}$ through core density ramps alone. The behavior of the
upstream plasma and geometrical divertor effects (e.g. a reduced connection
length with negative lower triangularity) do not fully explain the challenges
in detaching NT plasmas. Langmuir probe measurements of the target heat flux
widths ($\lambda_q$) were constant to within 30% across an upper triangularity
scan, while the spreading factor $S$ was lower by up to 50% for NT, indicating
a generally lower integral Scrape-Off Layer width, $\lambda_{int}$. The
line-averaged core density was typically higher for NT discharges for a given
fuelling rate, possibly linked to higher particle confinement in NT.
Conversely, the divertor neutral pressure and integrated particle fluxes to the
targets were typically lower for the same line-averaged density, indicating
that NT configurations may be closer to the sheath-limited regime than their PT
counterparts, which may explain why NT is more challenging to detach.
