  A major remaining challenge for $Nb_3Sn$ high field magnets is their training
due to random temperature variations in the coils. The main objective of our
research is to reduce or eliminate it by finding novel impregnation materials
with respect to the epoxies currently used. An organic olefin-based
thermosetting dicyclopentadiene (DCP) resin, $C_10H_12$, commercially available
in Japan as TELENE by RIMTEC, was used to impregnate a short $Nb_3Sn$ undulator
coil developed by ANL and FNAL. This magnet reached short sample limit after
only two quenches, compared with several dozens when $CTD-101K$ was used.
Ductility, i.e. the ability to accept large strains, and toughness were
identified as key properties to achieve these results. In addition, we have
been investigating whether mixing TELENE with high heat capacity ceramic
powders, increases the specific heat ($C_p$) of impregnated $Nb_3Sn$
superconducting magnets. The viscosity, heat capacity, thermal conductivity,
and other physical properties of TELENE with $high-C_p$ powder fillers were
measured in this study as a function of temperature and magnetic field. Mixing
TELENE with either $Gd_2O_3$, $Gd_2O_2S$, and $HoCu_2$ increases its $C_p$
tenfold. We have also investigated the effect on the mechanical properties of
pure and mixed TELENE under 10 $Gy$ of gamma-ray irradiation at the Takasaki
Advanced Radiation Research Institute in Takasaki, Japan. Whereas both
$TELENE-82wt\%Gd_2O_3$ and $TELENE-83wt\%HoCu_2$ performed well, the best
mechanical properties after irradiation were obtained for
$TELENE-87wt\%Gd2O_2S$. Testing a short undulator in the future with the latter
impregnation material will verify whether it will further improve the coils
thermal stability. Short magnet training will lead to better magnet
reliability, lower risk and substantial saving in accelerators commissioning
costs.
