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tours:faq [2019/03/18 16:15] constan [How LONG did it take to build the NSCL/Cyclotrons/other equipment?] |
tours:faq [2019/03/19 08:32] constan |
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===== Questions with Incomplete Answers ===== | ===== Questions with Incomplete Answers ===== | ||
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+ | ==== Why is the cycstopper standing on end, rather than lying flat like the K500/K1200? ==== | ||
+ | //(from Stefan Schwarz)// Main technical reason: the cyc-stopper is better at accepting large beams (in terms of emittance, i.e. beam width times angle) in its axial = horizontal direction, as built. | ||
+ | A bit of background: for the beam to stop efficiently in gas stoppers, it needs to have less energy spread than what we typically get from the A1900. | ||
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+ | To reduce that energy spread we use what’s known as momentum compression, i.e. the process of removing longitudinal energy spread with the help of a dispersive element (big dipole magnets in N3/4) and matched wedge-shaped degraders. However, since we bend/disperse the beam horizontally, the beam quality suffers in that plane. The cyc-stopper’s acceptance is higher in the horizontal direction when ‘standing’, so it’s able to make up for the larger beam emittance in that plane. | ||
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+ | There are also practical reasons: as built, the stopped beam will come out on the fixed south side of the magnet through the central bore. It’s a lot easier to construct an extraction beam line with this concept than taking the beam out through the top or bottom half in a ‘flat’ orientation. Also, access and work on the low-energy ion guides (carpets, conveyor) is a lot easier that way. | ||
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+ | FYI, we entertained the ‘flat’ orientation for a while in the early design phase, but for the reasons outlined above, we gave up on that rather quickly. | ||
==== How much water does the laboratory use? ==== | ==== How much water does the laboratory use? ==== |