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--- group_5 [2018/09/10 14:49]
flowerdew
+++ group_5 [2018/09/14 09:13] (current)
surbrook
@@ Line 1: / Line 1: @@
-**Monday 10th September**
+===Monday 10th September===
-* Group chose a <sup>15</sup>O + α reaction with SECAR.
+Question 3:
-* Example_1.fox was edited to include a dipole which bends the trajectory 45°.
+  * Group chose a <sup>15</sup>O + α reaction with SECAR.\\
-* <PD> (corresponding to ΔE/E) in coordinate SB was changed to 0.01 to create a small momentum spread.
+  * 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:\\
 {{screen_shot_2018-09-10_at_14.40.48.png|Trajectory of ray with small momentum difference }}
+  * PTY was changed to 3 to allow us to see the curvature: \\
+{{group5_screen_shot_2018-09-10_at_15.03.08.png }}
+Question 4:
+  * Used website to calculate θ<sub>max</sub> and ΔE/E
+    ** Opening angle = 0.59 deg = 10 mrad which is less than the θ<sub>max</sub>=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.\\
+{{:eandangle15oalpha.png?400|}}
+Question 5:
+  * Proton capture on <sup>15</sup>O one might expect from rp-process conditions is halted by the short half-life of <sup>16</sup>F (40 keV) and its proton emission back to <sup>15</sup>O. The two minute half-life of <sup>15</sup>O further acts to limit transitions out of <sup>15</sup>O, making <sup>15</sup>O a waiting point in nucleosynthesis in this mass region. \\
+  * <sup>15</sup>O + 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<sub>max</sub> 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.
+{{emittanceexample7.png}}
+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.
+{{Group5_screen_shot_2018-09-13_at_16.02.21.png }}
+  * 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.
+{{Group5_screen_shot_2018-09-13_at_15.48.23.png }}
+  * 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

JINA-CEE ION OPTICS SUMMER SCHOOL: JIOSS 2018

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