1. NuMI MINOS CM Review Magnetics Page 1 Magnetization options for the calibration module Jeff Nelson & Bob Wands Calibration module review (8/00) Simulations: status and impact 2 concepts –Pro/Con –Designs –Magnetics –Coil and steel requirements Conclusion –Probably the last talk you’ll ever see on this subject!

2. NuMI MINOS CM Review Magnetics Page 2 Simulations Peter’s Monte Carlo study found that fields in steel have negligible effect on showers –The air field is not implemented in GMINOS -- It should be studied –The air field is roughly »B  = 100 gauss / r(r in [m]) –Low energy particles won’t make it from the steel to the scintillator <0.3 MeV @ inner radii A CDHS NIM article also shows little effect on hadronic response Peter’s conclusion (in Jeff’s words) –“If it’s so small... let’s just make the spectral measurement in the near detector with & without field”

3. NuMI MINOS CM Review Magnetics Page 3 2 Options Need a magnetic circuit Box Option –Connect the tops & bottoms of two plates –Use one plate as the flux return for the other –Wrap power coils on the short legs »2 coils per pair of planes Flux Return Option –Use a larger steel plane put a hole off center and wrap a coil on it »Like the near detector! –Flux stays in a plane –Can power 2 planes with the same coil (more later) edge-on view face-on view scint area

4. NuMI MINOS CM Review Magnetics Page 4 Pros & Cons Pro –Box »Shape of planes nearly the same as the standard plane »Less steel, better access –Flux return »Fewer coils and lower power »The air field is in the right direction (parallel to the steel planes) Con –Box »The air field is in the wrong direction (normal to the planes) –Flux return »Mechanical headache »Air field is at the low end unless substantial power employed

5. NuMI MINOS CM Review Magnetics Page 5 Box Option:Integration with Scintillator 2 horizontal plates connect 2 planes making an open-sided “box” A module is slipped into the box and the next is connected to the outside of the box

6. NuMI MINOS CM Review Magnetics Page 6 Box Option Field in Steel The required current is roughly 1500 a-turns per coil Either design can repeated for as many pairs of planes as required

7. NuMI MINOS CM Review Magnetics Page 7 Coil Design Coils can be made like our test toroid –300 turns of 10 gauge insulated wire –15A power supply Repeat for each coil Readout system and coils for ~ $3500, existing supplies? 400 turn coil 15A power supply

8. NuMI MINOS CM Review Magnetics Page 8 The Flux Return Option Add 3 (thicker) plates to the edges to make a flux path 2 planes can be tied together using the same power coil Some manifolds are buried in the flux return

9. NuMI MINOS CM Review Magnetics Page 9 Flux Return Option Fields in Steel This design can yield lower fields at lower currents This plot shows the field with higher current to produce more air field –3000A-turns yields ~1.3T Instrumented Area

10. NuMI MINOS CM Review Magnetics Page 10 Air fields in the Flux Return Option Fields between planes ~ 9 to 11 gauss »3000 A-turns To get 100 gauss need »100 times the power -- Ouch! Half of the instrumented area

11. NuMI MINOS CM Review Magnetics Page 11 System based on that used for the 4PP and the table top toroids Automated readout via PC & Labview –Waveform digitizes integration-coil signals –Monitors power supply –Automated current control »Presets for hysteresis loop, degauss… –Expandable for multiple supplies Control and Monitoring V(t) B= A V(t)dt I(t) B vs I

12. NuMI MINOS CM Review Magnetics Page 12 Conclusions 2 options make reasonable fields in steel –Both use cheap coils & existing control systems Simulations show that the field in the steel in probably unimportant The field in the air may or may not be important –If it is… the flux return option is the only one that’s close »Many drawbacks –Size and shape makes issues for the mechanical support –Poor access to the manifolds if they are 1m modules –The actual field in the air is low –If not... flush this talk