OPTICS OF MICE STEP V.0

1
OPTICS OF MICE STEP V.0

• Ulisse Bravar
• University of New Hampshire
• 26 June 2005

2
MICE Steps
2006

2007

2008

3
MICE Step V.0 (1)
STEP V
STEP V.0
Should get 5-10 MV RF acceleration (limited by
dark current) Shorter, less expensive, no
coupling coil, (very limited optics flexibility)
does this work in flip, RFoFo, non flip modes?
These are mostly optics questions
4
MICE Step V.0 (2)

• Spectrometers and AFC modules same as in all
  other MICE configurations.
• NO coupling coil.
• 2 RF cavities rather than 4.
• RF dimensions do not change length
  of one cavity 43 cm.
• Spacing between AFC modules reduced
  LH to LH
  distance 2.75 m 1.35 m

5
Optics Goals (1)
p 200 MeV/c

• Find optic solutions for all MICE steps and
  configurations.
• i.e. choose currents for all 18 MICE coils to
  match the ?? function as desired.

r (m)
?? (m)
z (m)
?? 42 cm
6
Optics Goals (2)

• Solutions for flip/non-flip/semi-flip operating
  modes
• a) p 140, 170, 200, 240 MeV/c
• b) ?? 7, 15, 25, 42 cm in the middle of the
  LH2.
• Assume B 4 T in spectrometer for p 200, 240
  MeV/c.
• Scale B with p for p lt 200 MeV/c.
• Finding an optic solution means
• ?? has the desired value and a minimum in the
  middle of the LH2 absorber
• ?? has the desired value and d?? / dz 0 in the
  two spectrometers
• B is constant within 1 in the two
  spectrometers
• J, BSURFACE and coil forces are within limits.

7
Optics of StepV.0

• Fix the distance between the two AFC modules.
• Distance should be as small as possible, to
  reduce ?? increase in the RF section.
• Smallest distance 1.35 m.
• Once distance is fixed, absence of coupling coil
  implies there can be only ONE flip and ONE
  non-flip optic solution for StepV.0.
• To improve performance, new optics software using
  routine CONMIN.F90 from NASA AMES.

8
Non-flip Mode (1)

• Bz field
• p 200 MeV/c
• ?? min 7 cm,
• 4 cm from center
• of LH
• JFC 125 A mm-2

?? (T)
z (m)
9
Non-flip Mode (2)

• Beta function
• p 200 MeV/c
• ?? min 7 cm,
• 4 cm from center
• of LH
• JFC 125 A mm-2

?? (m)
z (m)
10
Flip Mode (1)

• Bz field
• p 200 MeV/c
• ?? min 14 cm,
• 11 cm from center
• of LH
• JFC 194 A mm-2

?? (T)
z (m)
11
Flip Mode (2)

• Beta function
• p 200 MeV/c
• ?? min 14 cm,
• 11 cm from center
• of LH
• JFC 194 A mm-2

?? (m)
z (m)
12
Conclusions

• Optic solutions for Step V.0 now available.
• Work needed
• A) do these solutions really work?
  i.e. determine cooling and scraping!
• B) are the currents, peak B-fields, RF
  E- fields and forces within tolerances?