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:
  

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

Question 4:

• Used website to calculate θ_max and ΔE/E
  • * Opening angle = 0.59 deg = 10 mrad which is less than the θ_max=25 mrad so we're good.
    
  • * ΔE/E = (12.083-11.593)/(12.083+11.593) ~2% which is less than the 3.1% threshold so this also works.
    

Question 5:

• Proton capture on ¹⁵O one might expect from rp-process conditions is halted by the short half-life of ¹⁶F (40 keV) and its proton emission back to ¹⁵O. The two minute half-life of ¹⁵O further acts to limit transitions out of ¹⁵O, making ¹⁵O a waiting point in nucleosynthesis in this mass region.
  
• ¹⁵O + α reaction plays a role in bypassing this waiting point in the ignition of type I x-ray bursts on accreting neutron stars, but the cross-section at relevant temperatures/energies has been experimentally inaccessible to date. The next generation recoil separators, St. George at Notre Dame and SECAR at NSCL/FRIB may reach sensitivity to this important reaction.
  

Question 6:

• Using 'WRITE 6 VMAX(RAY(1))' x_max 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