1. Booster bpm’s Jim Crisp 3/29/06

2. Plate width and linearity with the response linearized along the axis 60 and 20 degree plates become nonlinear in the corners 40 degree plates have the least distortion calculate 0.5db/mm (booster bpm’s are 0.52db/mm)

3. 50 or 25 ohms The even mode impedance is most important 50 ohm 40 degree plates won’t fit in the proposed magnet (60 degree plates worse) –3.916” plate ID for 5.465” bpm OD 25 ohm, 40 degree plates will fit –4.5” plate ID 5.228” bpm OD with 1/8” wall

4. Equivalent bpm Current booster bpm’s –4.625” plate ID, 60 degrees wide, 6” long, 6” bpm OD, –52.9 ohms even, 44.2ohms odd mode –Vplate/Ibeam 1.4 ohms at 53MHz –0.52db/mm 30-50MHz and 0.48db/mm at 200MHz Proposed bpm –4.5” plate ID, 40 degrees wide, 16” long Ideal (60/40)(50/25)6” = 18” correction magnet 17.5” flange to flange –25 ohms even 24.2 ohms odd –Vplate/Ibeam = 1.25 ohms at 53MHz (about 10% less) –0.50db/mm

5. Beam intensity range 25 ohms, 40 degrees wide, 16” long –(Correction magnet is 17.5” flange to flange) Rf module dynamic range -23.5 to +18.5dbm –-35 to +27dbm for AM to PM rf module –+1.5db for 100ft RG8 cable –+/-10db for +/-20mm position working range of beam intensity –8.4 to 1060e10 –(about the same as now)

6. Frequency response Peak at wl/c = pi/2 (plates 1/4 wavelength long) –185MHz for 16” and 492MHz for 6” plates Same response for terminated, open, or shorted stripline –200MHz linac beam 5.00/2.75 ohms (present/proposed) –37.9MHz at 400MeV 1.06/0.93 ohms –52.8MHz at 8GeV 1.40/1.20 ohms Use 50ohms at bpm output to terminate stripline

7. rf modules (MI 0.48db/mm Hor, 0.42db/mm Ver) MI rf module, similar for booster

8. Wall thickness and magnetic fields magnetic fields will be attenuated and delayed inside bpm round pipe acts like low pass filter (approximate) –n = 2 for dipole (4 for quadrupole etc) –ρ = 9.0e-7 ohm-m for stainless steel –R = 3” radius –t = 1/8” wall thickness –f ~ 942Hz t ~ 170usec –The 4 plates will also distort a changing magnetic field above this frequency –Frequency where 1/8” = skin depth f = 22.6KHz What are the frequency components of the correction fields? –(30-50MHz external magnetic fields will never reach the plates)

9. Measured fields in pipe 1/8” wall 2” ID Aluminum pipe Solid is calculated using Mafia – Ostiguy Red curve from simple formula Points are measured with hall probe

10. Cross section Proposed design Type N feed through on one end Short other end 16” long plates

11. A few details Proj 22 Task 1.02.03.01 deliver nearly the same signal to the rf modules –Lowest intensity 1 turn of 30mA or about 40e10 24 long and 24 short locations (use same bpm) 60 magnets will be made Need survey fiducials to measure bpm location in tunnel –Use same fiducials on bpm test stand –survey position and rotation tolerances? Allowable wall thickness / bandwidth of correction fields –Rise times of 2 msec –Eddy current heating may be a problem (correctors ramped at 15Hz) radiation exposure over the expected life time? –Few locations measured at 20KRad/month (MRad/lifetime) Vacuum acceptance criteria –Flanges should be angled to match bend magnet –Assembly may require a bellows Bpm should be made very reliable and thoroughly tested before installation, requires replacing magnet to change May request cable strain relief bracket on magnet Prototype bpm for test June 2006 First 24 required February – April 2007 Installation June 2007