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group_5

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Monday 10th September

Question 3:

  • Group chose a 15O + α reaction with SECAR.
  • Example_1.fox was edited to include a dipole which bends the trajectory 45°.
  • <PD> (corresponding to ΔE/E) in coordinate SB was changed to 0.01 to create a small momentum spread:

Trajectory of ray with small momentum difference

  • PTY was changed to 3 to allow us to see the curvature:

Question 4:

  • Used website to calculate θmax and ΔE/E
    • * Opening angle = 10 mrad which is less than the θmax=25 mrad so we're good.
    • * ΔE/E = ~2% which is less than the 3.1% threshold so this also works.

Question 5:

  • 15O + α reaction plays a role in the ignition of type I x-ray bursts on accreting neutron stars

Question 6:

  • Using 'WRITE 6 VMAX(RAY(1))' xmax was calculated to be 0.2909704181068736E-002 m
  • Plotting COSY beam size (x) and the quadrupole field strength(divided by aperture radius) and arrived at the graph below. Data doesn't appear to fit the quadratic form too closely.
  • Calculated emittance is about 0.3 mm mrad, which is 50% larger than the 'real' emittance.

Question 7:

  • Effective field length of Q2 was increased by 3% and the drift lengths either side were adjusted accordingly, so as not to change the the centre position of the quadrupole.
  • The mass resolution was then optimised by minimising the function OBJ := 1/ABS(MRESOL_P1) by varying the strength of Q2, Q3 and Q4.
  • This would increase the mass resolution to values of up to 85,000, however the emittance was very large.

  • We realised that we should alter our objective function, in order to re focus our beam. This was achieved with the function OBJ := 1/ABS(MRESOL_P1) + ABS(ME(1,2)), where we added on the (a|x) matrix element to also minimise.

  • This optimisation improved the mass resolution from 640.86349 to 724.66207, while still focusing.

Question 8:

  • Tolerance for the beam size was found to be 0.00075 +/- 0.00004 m
  • Tolerance for the beam position was found to be +/- 0.007 m
/srv/thewikis/JIOSS/data/attic/group_5.1536870429.txt.gz · Last modified: 2018/09/13 16:27 by flowerdew