Feb 11, 2011 Replacement Solenoid

Items for followup from previous meeting

1. 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
2. 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
3. High-current HTS (17KA) vapor cooled leads
   • Ettore will provide this information based on Sultan design
4. 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

1. 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?

1. 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, Mitch Laney, Catherine Ware (MIT Chief Fiscal Officer on the phone),

1. Drawings
   • Add space envelop for cryogenic can/connections on top of magnet (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)
2. Requirements and Interface Document (MIT will start with draft and iterate with JLab)
   1. 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
   2. Implementation
      • MIT to provide server read access to documentation
      • JLab to approve and keep controlled documents
3. 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.
4. Discussion: Why investigate the CIC option?
   1. Qualitative arguments (Ettore)
      • higher current -> less conductor -> fewer splices inside windings, more robust
      • higher current density -> more compact coil, possible gain in performance
   2. Comments (Joe)
      • 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]

Attending Afternoon discussion on infrastructure: Ettore, Elton, Joe, Phil, George Biallas, Tim Whitlatch, Elliott Wolin, Jonathan Creel, Rao Ganni.