tube beam dump https://dcc.ligo.org/DocDB/0105/D1300548/001/D1300548%20Beam%20Dump%2C%20Fast%20Shutter%2C%20HAM1%2C%20aLIGO.PDF
OFI shroud https://dcc.ligo.org/DocDB/0151/D1800103/006/D1800103-v6.PDF
isc beam dump https://dcc.ligo.org/DocDB/0011/D1001076/005/D1001076_ISC_TRANSMON_HIGH_POWER_BEAM_DUMP_v5.PDF
isc small beam dump D1800200-v1.PDF