Dear Wim,

I have checked the apertures that we have in the transfer line files in the elements

DIS : square aperture 50 mm hriz, 100 mm vertical .

DVT : bore diametre 140 mm 

SMV : square aperture 68 mm (horiz) 30 mm vertical

BVT : bore diameter 140 mm

In the DIS and SMV the ratio between the aperture and rms beam size is around 5 for  both planes. This is as low as we feel confortable to go, so these apertures shouldn't be reduced further.

In the DVT and BVT, we have some margin, so if you want to reduce the aperture by some 20 % we can discuss.

Let me know, alessandra