Magnets for Mu2e Resonant Extraction: Design and Scope Changes V.Nagaslaev 05/09/2013

Scope at CD1 and now 1.Lambertson septum magnet  New design in work  Out of scope now (in g-2) 2.Octupole magnets  Discontinued 3.Harmonic ramp quads  Discontinued 1. Sextupole magnets (6)  ISA type magnets costed 2. Tune ramp quads (3)  CQA type quads costed 3. DEX bump trims (4)  New scope Scope at CD1 Scope now

Sextupole magnets: evolution of specs  n  · mm·mr  m #magnets in circuit Safety margin 30% Gradient, T/m Original spec 6No40 ORBIT No60 Synergia No60 CDR10 3Yes150 Realistic spec? Yes80 ISA magnets rated up to 60 T/m, which is in our definition equivalent to 120 T/m integrated strength. This covers very well the “realistic” spec of 80T/m. But we may have to add water cooling to the design.

Tune ramp quad magnets  m #magnets in circuit Safety margin 30% Gradient, T Original spec 3No0.15 CDR103Yes0.26 Realistic spec?12.83Yes0.2 CQA specs ?

Dynamic angle bump at ESS (DEX bump). Need this bump to improve efficiency As Local as Reasonably Achievable Fast ramping capability is required

What is the dynamic bump and why do we need it? In the process of extraction, as the separatrix squeezes, the angle particles approach ESS is changing. This results in increase of the beam losses on the septum foil plane. This can be compensated by the dynamically changing local angle bump at the ESS1. Colors don’t match!

Making a local bump in the 30 straight Injection kickers Injection Lambertsons Extraction septa (Mu2e) Extraction Lambertsons Extraction kicker (g-2) Delivery Ring 30 Straight Section Plan DEX trims ? New

Extraction Dynamic Bump model (DEX bump) ΔI max =7A Q203X=0;X’= 0.4mR Q205X=5.3mmX’=0 Q301X=-5mmX’=0 Q303X=-5.3mmX’=0 D:H209, D:H206, D:H301, D:H305 2Q10 2Q7 2Q5 3Q0 3Q3 3Q5 H210 H206 H301 H305 P beam This is a substantial bump. The position moves are noticeable and the trim current is hard to drive at required rate.

Hardware NDA/NDB trim magnets: H206, H301 are in place H302 is displaced  move it to 305 H209 to be installed in the missing dipole arc section Spare magnets are available Waveform controlled bulk supplies installed in straight for both Deb and Acc. We can reuse the Accumulator one. This PS is voltage limited at V=150V

How fast can be the bulk supplies driven? The PS drive voltage is limited by the regulator at 150V This is at least 2 times slower than we need. Most likely we’ll need to pay for extra voltage regulator in the PS

DEX bump trims NDB is a cheap, attractive option, however there is an issue of available ramp speed. Are there by any chance other option with lower inductance? Otherwise should be easy to cost.

Resonant Extraction Tune Quadrupole Magnets This estimate assumes the availability of reasonably good existing CQA magnets which would be refurbished through a defined process including (but not limited to): Acceptability inspection; disassembly; refurbishment of coils and cores; re-assembly with additional parts to secure coils onto the cores; and final inspection. Magnetic measurements and survey would follow. Note that ~40% of the M&S is reserved for the magnet stands. As this is an existing magnet, minimal R&D is expected. R&D is expected to be limited to computer simulation of the expected magnet performance and thermal rise for duty cycle. The total M&S cost in the “Implementation Labor and M&S” table was rounded up from $7.4K to $8K. Contingency rules and were used to estimate contingencies. Increased contingency due to uncertainty in suitability of existing magnets to be refurbished.

Resonant Extraction Sextupole Magnets This magnet design is similar to an existing ISA magnet built in the mid 1990’s. The lamination is thinner and the coils are expected to be air-cooled. Tooling, including the stamping die, is believed to exist but would need to be verified. The original manufacturing record of this magnet exists and has been pro-rated to current M&S, labor values and quantity adjustments. EDIA was added at standard Technical Division rates. As this design has been fabricated before, the default contingency would be 30% but the M&S uncertainty of commodity pricing for copper and steel forces a contingency closer to 50%. As this is an existing and proven design, minimal R&D is expected. R&D is expected to be limited to computer simulation of the thinner laminations and thermal rise for duty cycle. Contingency rules and were used to estimate contingencies.

What needs to be done o Revisit the magnet choice options o Re-evaluate cooling needs for each magnet type o Revisit cost and schedule estimates for all magnets o Define the schedule. Right now only the PD phase is defined. o Create the new BOEs o This is likely to be the Final Design!