Feb 11, 2011 Replacement Solenoid
From GlueXWiki
Items for followup from previous meeting
- Power supply. Current ~ 15KA, voltage 5-10 V. (Could existing power supply 3KA/10V be converted to 6KA/5V?)
- Elton will obtain cost estimates for this power supply
- Cryogenic plant: Primary circuit: Forced flow He at 4.5K, < 10g/s, ~5-10 bar, pressure drop < 2 bar. Secondary circuit: Deliver intermediate temperature He gas at 20-70 K to HTS vapor cooled current leads
- Jonathan will investigate feasibility/cost of modifying existing refrigerator or purchasing new to deliver these requirements. Provide details to Ettore
- High-current HTS (17KA) vapor cooled leads
- Ettore will provide this information based on Sultan design
- Fast protection system (external), with response time of ~0.5 s. Commercial 4 parallel breakers 5KA each (20KA total), 2KV max. Two independent systems for redundancy.
- Ettore will obtain details of these existing systems.
Tentative Agenda
- Power supply
- maximum current capability
- How much the PS can be modified to increase the current capability
- bus bar capability. Can cables be used, or are air/water cooled bus bars required?
- Cryogenic plant
- Is a secondary loop practical/feasible with an intermediate heat exchanger and recirculating pump in order to comply with the pressure (~6 bar) and pressure drop (~0.5 bar) needed for the CIC conductor.
Minutes
Attending Morning: Joe Minervini, Phil Michael, Elton, Ettore, Glenn, Lionel Quettier, Mitch Laney, Catherine Ware (MIT Chief Fiscal Officer on the phone),
- Drawings
- Add space envelop for cryogenic can/connections on top of magnet. Drawing should include expected iron cladding. Also add location of transfer lines. (Tim)
- Provide building information for use in considerations of installation and operation. Hall D has a 20 T crane.
- Update B-field table with values for "preferred shape" (LASS values) (Elton)
- Saturation curve for steel. (Tim suggest the use of 1010 steel properties)
- Specify radiation environment in hall. To start give power deposited per volume inside coils. [Note: For Hall D rates this will likely not be a problem, but good to document] (Elton)
- Requirements and Interface Document (MIT will start with draft and iterate with JLab)
- Items to add in random order
- duty cycle of magnet
- possibility of reversing polarity (start assuming reversing should be possible, but infrequent --check protection system and diode stacks)
- consider assembly and operations
- add specification of 5 G boundary
- Investigate operation of magnet at 2.5 T with existing design with out modifications.
- Revisit saturation of iron by adding iron to fill in regions currently occupied by existing magnet infrastructure. Could possibly also add more iron in "coil volume" for thinner coil
- Implementation
- MIT to provide server read access to documentation
- JLab to approve and keep controlled documents
- Items to add in random order
- Discussion of Hall B experience with Rutherford cable (Lionel)
- Lionel showed pictures and discussed Hall B experience with soldering the Rutherford cable into Cu channel.
- Procurement issues
- terms and conditions seem to be ok on first glance
- MIT will give feedback to Mitch as soon as possible.
- An extension of the RFP will be granted to allow for necessary review time.
- Discussion: Why investigate the CIC option?
- Qualitative arguments (Ettore)
- higher current -> less conductor -> fewer splices inside windings, more robust
- higher current density -> more compact coil, possible gain in performance
- Comments and discussion
- could lead to higher cryogenic loads
- pricing of high temp leads might be high. Ettore: Should use existing HT current lead design, even for higher performance to save design/testing effort. HT lead designs include 6kA (CERN), 17kA (Sultan)
- Note: burn out time for leads ~ 10x fast dump time.
- Might require intermediate temperature for current leads of about 50-70k, below 80k for nitrogen. [Ganni commented later that 4K should be used with adjustable flow rate to adjust temperature]
- Qualitative arguments (Ettore)
Attending Afternoon discussion on infrastructure: Ettore, Elton, Joe, Phil, George Biallas, Tim Whitlatch, Elliott Wolin, Jonathan Creel, Rao Ganni.
- Power Supply
- Guestimates of modifying existing power supply for currents exceeding 3KA would not save much compared to purchasing a new supply at about $150K.
- Decision not to constrain the conceptual design for either conductor type by attempting to use existing supply. New PS would also be outfitted with a new dump resistor and protection system.
- Cryoplant
- Ganni emphasized that secondary pump loop was not effective use of resources (modification costs equalled new refrigerator and maintenance problematic)
- Existing refrigerator could be reconfigured to provide a 5-6 atmosphere input pressure to provide an output pressure of about 3 atmospheres. This should be sufficient for even the CIC design, but implementation can be reviewed at the time that the conceptual design provides actual parameters.
- Existing refrigerator should be able to handle a magnet consuming 50W at 5g/s. Current magnet operates at 100W at 0.3 g/s.
- Intermediate temperature for HT leads: Rao suggests using 4K liquid, and adjusting the flow to achieve the desired temperature.
- Preferred option is to use a bath, but other options can be accommodated depending on the magnet design
- Jonathan (Rao) will provide a spec sheet for the cryo plant to MIT