Determining DRAGON's acceptance: a Microscopic view
DRAGON measures the resonance strengths of nuclear reactions using beams from the ISAC facility, this resonance strength is fundamental in calculating the rates at which elements are created and destroyed in the interior of stars and during explosions like supernovae and novae. A key component of the resonance strength is the yield mea- surement. For an accurate measurement of the yield, various efficiency fractions must be known including the efficiency of the DRAGON mass spectrometer. This report presents measurements taken with a 148Gd α-source mounted in the gas target of DRAGON, this simulates a reaction with a cone angle of ≈ 20 mrad. A collimator is used that allows a microscopic view of particle transmission in DRAGON. Results suggest that the gas target box axis is lower than the separator axis by ≈ 2 mm, Q1’s ’standard’ setting is high by ≈ 5%, there is a possible quadrupole misalignment between the two electric dipoles of DRAGON which decreases the transmission of particles emitted to the left (looking upstream), and finally there is a possible misalignment that causes a x − y correlation at the final slits. Simulations with GEANT have been performed to test these conclusions with mixed results. Conclusions and recommendations are presented.
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