The sensors used by HEPI-ITMY look functional. The attached plot shows the spectra of the L4Cs and the STS-2 (ground instrument).
STS-2 signals from HEPI-BSCs are broad-casted to the other chambers via a STS-2 distribution chassis (D0900351).
STS-2 signals seen by HEPI-HAM2 et HEPI-ITMY are identical (cf spectra).