  We present Atacama Large Millimeter Array (ALMA) observations of TW Hya at
3.1 mm with $\sim50$ milliarcsecond resolution. These new data were combined
with archival high angular resolution ALMA observations at 0.87 mm, 1.3 mm, and
2.1 mm. We analyze these multi-wavelength data to infer a disk radial profile
of the dust surface density, maximum particle size, and slope of the particle
size distribution. Most previously known annular substructures in the disk of
TW Hya are resolved at the four wavelengths. Inside the inner 3 au cavity, the
2.1 mm and 3.1 mm images show a compact source of free-free emission, likely
associated with an ionized jet. Our multi-wavelength analysis of the dust
emission shows that the maximum particle size in the disk of TW Hya is $>1$ mm.
The inner 20 au are completely optically thick at all four bands, which results
in the data tracing different disk heights at different wavelengths. Coupled
with the effects of dust settling, this prevents the derivation of accurate
density and grain size estimates in these regions. At $r>20$ au, we find
evidence of the accumulation of large dust particle at the position of the
bright rings, indicating that these are working as dust traps. The total dust
mass in the disk is between 250 and 330 $M_{\oplus}$, which represents a
gas-to-dust mass ratio between 50 and 70. Our mass measurement is a factor of
4.5-5.9 higher than the mass that one would estimate using the typical
assumptions of large demographic surveys. Our results indicate that the ring
substructures in TW Hya are ideal locations to trigger the streaming
instability and form new generations of planetesimals.
