A large-bore, 4T solenoid magnet facility for development of novel detector applications Peter Winter

The MRI magnet from Univ. of Minnesota LDRD Brainstorming, April 28,  4T, ActiveShield technology MRI magnet available (type OR66)  Large bore of up to 90 cm diameter, ~2m long  Magnet comes with power supply, cold-head and compressor, and other equipment and should be operational  Installation requires cool-down, ramping and shimming (passive and active shimmming)  Pretty excellent specifications:

Immediate purpose of magnet is for g-2  The stable magnet is needed to test all our NMR equipment at the level of better than 20 ppb  Test the 50cm long, ~20cm diameter NMR trolley needs large bore magnet  A stable and homogeneous magnet is needed so that the field is not the limiting factor while studying all effects stemming from the NMR equipment (temperature, position errors of probes coupling to field gradients, voltage drifts, electronics effects, S/N,...). LDRD Brainstorming, April 28,

Since LDRD is seed money, need application(s) to sell as a long-term facility:  Test novel detectors in high fields of up to 4T: –ICARUS detector might come to FNAL for short baseline neutrino physics, one can test LArTPC with SiPMs in magnetic fields –Structural tests of motorized collimator for Mu2e –60cm diameter tracker prototype for ILC in T –Power pulsing tests for future colliders at 3 - 4T  Use for new experiments (at FNAL): –Improve on the muonium hyperfine measurement –New idea for axion dark matter search (arXiv: , Aaron Chou) –Physics division really interested to use with FRIB (we actually might get a second OR66 from UCSF / DoD)  Magnet even comes with MRI equipment but that would require much more complicated installation (RF shielding,...) LDRD Brainstorming, April 28,

Location at Argonne available LDRD Brainstorming, April 28, Big hall (building 366) Dedicated room for magnet, currently used for g-2 trolley drive and garage refurbishment

Activities that need be done  Install and cool-down magnet (requires safety review and recirculating chiller, 6500 liters of LHe)  Learn how to ramp magnetic field up to 4T (have magnet power supply)  Develop passive and active shimming including OPERA-3D simulation (needed for g-2)  Design multi-use platform (NMR probe testing with temperature control needed for g-2) LDRD Brainstorming, April 28,

Questions for LDRD  If all of the activities are done for g-2 anyway, so why would we need additional LDRD money?  How to sell support for larger facility, rather than seed funding for a specific research idea?  Would it be better to engage in one of the specific long-term applications to make a good argument for an LDRD?  What would one best ask for? (PostDoc, operating costs, funding for specific research activity...) LDRD Brainstorming, April 28,

Backup slides LDRD Brainstorming, April 28,

g-2: It’s all about systematic uncertainties LDRD Brainstorming, April 28, Systematic uncertainties field measurement E821 [ppb] E989 goal [ppb] Need of stable and homogeneous test magnet Absolute calibration of standard probe 5035Need to study various effects at better than 20ppb each, test new absolute probe Calibration of trolley probes 9030Study effects of relative probe positioning, T drift of samples Trolley measurement of B Interpol. with fixed probes7030Test and carefully study individual 400 probes’ digitized NMR signal (not determined by magnet) Muon distribution3010 Others10030Study effects of T and voltage drift of electronics, test new probe shapes Time-dependent fields-5 Total17070

Costs* for bringing this MRI magnet to ANL LDRD Brainstorming, April 28, Cost typeUnits needed Price per unit Total costComments Transport1$3,000 $4,500 actuals Rigging on-site40h$100$4,000My estimate, needs refinement Piping / safety notes80h$160$12,800My estimate, needs refinement Cryogenics (LN2)6000 l$0.50$3,000One-time cooldown, info Bruker Cryogenics (LHe2)6000 l$7$42,000*One-time cooldown, info Bruker Installation80h$120$9,600My estimate, needs refinement M&S installation$15,000Mainly a chiller (~$9k) plus piping Compressor maint.$5,000Info from physics colleagues Cooldown160h$120$19,200MRI Technologies: $15-18k Total cost$113,600 Operating cost: ~$15k helium/year and $5k compr. maintenance every 18 months * covered by g-2 project at FNAL!

Requirements for g-2 LDRD Brainstorming, April 28, Requirements for g-2 Comments Magnetic field strength>1.45 T g-2 needs 1.45T Stability< 120 ppb / h Less than 10ppb field drift during 5 minute probe change Homogeneity over a few cm< 200 ppb/cm Less than 10 ppb coming from assumed probe placement precision of ±0.5mm Bore diameter> 60 cm 50 cm trolley needs to be orthogonal to solenoid axis Continuous usage time~4-6 months in 2014/15 ~1-2 month each in Careful systematic studies require time and stable conditions (permanent platform and temp. control)

Location at Argonne available LDRD Brainstorming, April 28,  Restricted room almost confines 5G stray field, high magnetic field safety no big issue, conference room will become restricted lab, too.  We need a 10l/min, 8kW chiller for compressor  ODH could be easily solved opening the roof so that 2,000,000 liters of helium gas just cover 1m below roof of big hall (like at HELIOS)  Exclusive usage for g-2, then open to any other user (ANL, FNAL,...) pending availability