A search for double $\beta$ decay of dysprosium was realized for the first time with the help of an ultra low-background HP Ge $\gamma$ detector. After 2512 h of data taking with a 322 g sample of dysprosium oxide limits on double beta processes in $^{ 156}$Dy and $^{ 158}$Dy have been established on the level of $T_{ 1/2}\geq 10^{ 14}-10^{ 16}$ yr. Possible resonant double electron captures in $^{ 156}$Dy and $^{ 158}$Dy were restricted on a similar level. As a by-product of the experiment we have measured the radioactive contamination of the Dy$_2$O$_3$ sample and set limits on the $\alpha$ decay of dysprosium isotopes to the excited levels of daughter nuclei as $T_{ 1/2}\geq 10^{ 15} - 10^{ 17}$ yr.
Categories: nucl-ex