Upgrade of the TAMU MDM-focal plane detector with MicroMegas technology

Abstract

A gridded ionization chamber used as a focal plane detector at the back of the TAMU-MDM spectrometer was modified to use MicroMegas technology for the purpose of improving energy resolution and particle identification. The upgraded system was tested in experimental conditions with several heavy-ion beams at 12 MeV/u and found to achieve resolutions between 3.2% and 4.8%. This is a significant improvement over the previous performance of 10-15% obtained using the existing, conventional ionization chambers.

Decay properties of 22Ne + α resonances and their impact on s-process nucleosynthesis

“…Elastically scattered target nuclei were detected in a series of resistive strip detectors in a barrel configuration (θ lab = 45 • -145 • ). Beamlike 26 Mg ( 25 Mg) recoils resulting from γ-ray (neutron) decay of 26 Mg excited states were unambiguously identified in the MDM focal plane using a combination of energy loss, total energy, and dispersive position signals from the upgraded Oxford detector [33,34], as demonstrated in Figure 1. The identification of 25,26 Mg recoils was confirmed by the coincident γ-ray transitions measured in the HPGe detectors.…”

“…To account for spin dependence, separate simulation runs were performed for L = 0, 1, 2 transitions and the weighted average was taken as the final acceptance. The acceptances of 25 Mg and 26 Mg recoils were determined to be 77.8(11)% and 90.8(5)%, respectively, resulting in a 25 Mg/ 25 Mg efficiency ratio of 0.858 (33). Figure 2(a) shows the angle-integrated (θ CM = 6 • -14 • ) 26 Mg excitation energy spectrum measured by the annular Si detector.…”

Study of ($^6$Li, $d$) and ($^6$Li, $t$) reactions on $^{22}$Ne and implications for $s$-process nucleosynthesis

“…The MDM spectrometer downstream of the target transports particles scattered at forward angles less than θ lab =±2 • in both the dispersive (x) and non-dispersive (y) planes. Transported particles are detected in the Oxford detector [49,50]. The Oxford detector consists of three ionization detector zones and four wire proportional counter zones.…”

New constraints on the Al25(p,γ) reaction and its influence on the flux of cosmic γ rays from classical nova explosions

“…Here, an ≈ 0.1-pnA, 10-MeV/u beam of 25 Mg ions was used to bombard a 200-μg/cm 2 -thick target of polydeuterated ethylene (CD 2 ) n . Light charged particles were detected with the TIARA Si array [46], whereas 26 Mg recoils were identified at the focal plane of the MDM-2 magnetic spectrometer [47] using the upgraded Oxford ionization chamber [48,49]. In this setup, elastically scattered deuterons were detected just forward of 90 • , providing an absolute normalization of all differential cross sections, and protons resulting from the (d, p) reaction were detected over the angular range of θ lab = 137 • -169 • .…”