I studied the effect of black glass in the manifold ports at Y-end, comparing black glass in all six ports to no blocks in any port. I compared both with no injection, Figure 1, and with an acoustic injection that excited scattering peaks normally a little below the DARM floor, Figure 2. No effect was seen. I didn’t have time to do the complete multi-port study at X-end, but I had to excite more there to bring up scattering peaks, so I think there is somewhat less of a potential problem there. I left one of the new black glass blades in the Pcal camera port at each end station, though I had found no evidence of a problem at either station.