D0 Silicon Upgrade: Transfer Line Branch Considerations for Solenoid & VLPC
The transfer line for the solenoid currently has a dead branch on it. Issues regarding the solenoid transfer line also apply to the VLPC transfer line. Issues that need to be addressed are: (1) What is the heat load on the branch? (2) Would it be a good idea to run the LN2 radiation shield on the branch? (3) What are the thermal acoustic oscillation parameters of a dead headed branch? A simple remedy, although not analyzed was to install a jumper with a flow restriction at the end of the helium piping to allow a small flow to pass from supply to return. Thus eliminating a stagnant gas volume in which pressure pulses would develop. (4) Do we need to have a vapor trap to keep liquid from sloshing back and forth from the cold end to the warm end? (5) Comment: The tee that passes the 2-phase return into the nested LHe supply/return pipe should be pointed up so that the volume of transfer line acts sort of like a phase separator full of liquid. It is very difficult to predict the behavior of the dead ended branch. Therefore the conservative thing to do is to keep the Branch cold as in option A. Use a valve inside the bayonet box for the LHe. Due to space constraints, use a valve and u-tube arrangement for the LN2. The additional heat leak from keeping the section cold is very reasonable. The heat load to LHe is 0.8 W or 2.3 W and to LN2 is 13 W or 71 W when the detector is run in the collision hall or assembly hall respectively. To prevent thermal acoustic oscillation from occurring in the dead ended female bayonets, we can install male bayonet vacuum plugs. The heat load to the system and behavior of such an arrangement will not provide any surprises, unlike a dead ended branch. It also allows flexibility's such as running the helium refrigeration plant without the detector for tests or for precooling the return lines during cooldown, just to name a few. The LHe control valves should have actuators and be able to be remotely controlled. The LN2 valves can be simple manual valves that will probably not be adjusted after their initial setting.
- Research Organization:
- Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- AC02-07CH11359
- OSTI ID:
- 1033307
- Report Number(s):
- FERMILAB-D0-EN-424; TRN: US1200384
- Country of Publication:
- United States
- Language:
- English
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