1 Sasha Milov HBD internal... July 10, 2007 New divider floating vs. grounded Sasha Milov July 10, 2007

2 Sasha Milov HBD internal... July 10, 2007 New divider Some other changes: a)GEMS are not shown because they are made of 28 R/C and are huge. b)No change in the results compare to the old scheme found c)In the scheme on the left PS shorts to zero at a trip time. I used 1ms fall time and 1Meg residual resistance on the PS R out. d)Changing R out to zero does not really change much, anyways. Bot Mid Top Mesh

3 Sasha Milov HBD internal... July 10, 2007 Float vs Ground topGEM-mesh across GEMs across transfer gaps float ground

4 Sasha Milov HBD internal... July 10, 2007 Float vs Ground Ground scheme has advantages: a)transients dV are smaller (even with R out = 0 they are so) b)GEM discharges faster c)Transfer gaps flip sign “momentarily” so to prevent any affect on lower GEM. Here is my understanding of Floating vs. Grounded PS: In case of a trip one would like to drain energy form the divider. Regardless of the PS, the scheme must have such drainage system with matching R/C’s. We learned it a hard way. Floating PS leaves transient process fully at hands of that drainage system. Grounded PS provides one more sewer, which if all R/C match properly gives another factor in speed, thus safety. Bob and me measured BERTAN yesterday found it floating with R out = 150M (guess at Fluke’s limit…)

5 Sasha Milov HBD internal... July 10, 2007 New vs Old dividers topGEM-mesh across GEMs across transfer gaps new (float) old (used)