MAYA, a gaseous active target

Demonchy, C. E.; Mittig, W.; Savajols, H.; Roussel‐Chomaz, P.; Chartier, M.; Jurado, B.; Giot, L.; Cortina-Gil, D.; Caamaño, M.; Ter-Arkopian, G.; Fomichev, A. S.; Родин, А. М.; Golovkov, M. S.; Stepantsov, S. V.; Gillibert, A.; Pollacco, E. C.; Obertelli, A.; Wang, H.

doi:10.1016/j.nima.2006.11.025

Cited by 47 publications

(26 citation statements)

References 4 publications

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“…A technical description can be found in [7]. We may mention that to our knowledge this may be one of the last projects in our domain of this importance that was realized without being controlled and approved by technical and financial committees.…”

Section: Mayamentioning

confidence: 99%

Active targets for the study of nuclei far from stability

Beceiro-Novo

Ahn

Bazin

et al. 2015

Progress in Particle and Nuclear Physics

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Section: Mayamentioning

confidence: 99%

Active targets for the study of nuclei far from stability

Beceiro-Novo

Ahn

Bazin

et al. 2015

Progress in Particle and Nuclear Physics

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“…With respect to the experimental constraints mentioned above an active target is the key to measuring the isoscalar monopole response in unstable nuclei. The active target MAYA, developed at GANIL [22] for nuclear physics experiments, is a time projection chamber (TPC) with an active volume of a 28 × 25× 20 cm 3 . Electrons produced from the ionization of the gas by charged particles traversing its volume drift in an applied electric field to a set of 32 amplification wires that are parallel to the beam direction.…”

mentioning

confidence: 99%

“…For a two-body reaction, scattered and recoiling particles are in a plane which can be determined using the drift time required by the electrons to reach the wires. The avalanches on the wires induce signals on a matrix of 32 × 32 hexagonal pads connected to GASSIPLEX [22] chips. MAYA was filled with He gas, at a pressure of 500 mbar (with 5% CF 4 used as a quenching gas) and was positioned at the end of the LISE beam line.…”

mentioning

confidence: 99%

Measurement of the Isoscalar Monopole Response in the Neutron-Rich NucleusNi68

Vandebrouck¹,

Gibelin²,

Khan³

et al. 2014

Phys. Rev. Lett.

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The isoscalar monopole response has been measured in the unstable nucleus 68 Ni using inelastic alpha scattering at 50A MeV in inverse kinematics with the active target MAYA at GANIL. The isoscalar giant monopole resonance (ISGMR) centroid was determined to be 21.1 AE 1.9 MeV and indications for a soft monopole mode are provided for the first time at 12.9 AE 1.0 MeV. Analysis of the corresponding angular distributions using distorted-wave-born approximation with random-phase approximation transition densities indicates that the L ¼ 0 multipolarity dominates the cross section for the ISGMR and significantly contributes to the low-energy mode. The L ¼ 0 part of this low-energy mode, the soft monopole mode, is dominated by neutron excitations. This demonstrates the relevance of inelastic alpha scattering in inverse kinematics in order to probe both the ISGMR and isoscalar soft modes in neutron-rich nuclei. Measurements in exotic nuclei have yielded an abundance of new information in recent years. For instance, a more general view on magicity has emerged in the past decade [1]. It has also been suggested that measurements of giant resonances in exotic nuclei could help clarify another important problem related to nuclear incompressibility [2]: despite significant progress in our understanding of the nuclear incompressibility, one cannot converge towards a value that is more accurate than the 10%-20% level. In other words, it seems difficult to single out an energy density functional that can give a comprehensive description of the ISGMR, especially in keeping with new data on isotopic chains including open-shell systems and on neutron-rich nuclei [3][4][5][6]. This can be seen in the recent theoretical works on the subject [7][8][9][10][11][12]. The measurement of the ISGMR in exotic neutron-rich nuclei is, therefore, of paramount importance. Such measurements in exotic nuclei would significantly improve our understanding of nuclear incompressibility as was the case for nuclear magicity in the past decade. In addition, a soft monopole mode has been predicted around 14 MeV in neutron-rich nuclei by several relativistic and nonrelativistic models [13][14][15], but it has never been observed, due to the difficulty in measuring the monopole response in nuclei far from stability. The soft monopole mode is predicted to be noncollective and its observation could bring valuable information on spin-orbit splitting [16]. It is therefore essential to measure the isoscalar (in-phase motion of protons and neutrons) monopole response in neutron-rich nuclei.The measurement of giant resonances in unstable nuclei is a particularly challenging task and has, until now, been mainly limited to the isovector (protons and neutrons out of phase) giant dipole resonance in neutron-rich radioactive O, Ne, Sn isotopes, and in 68 Ni [17]. Such measurements provided the first evidence for soft isovector dipole modes in unstable nuclei. These modes are often reanalyzed, showing a nontrivial pattern, departing from the simple pygmy resonance pictu...

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“…Fig. 17 The MAYA detector [66] is an active target in the sense that the gas that fills MAYA acts both as the target for the nuclear reactions and also as the fill gas of a time projection chamber. Ionisation paths in the gas are drifted to readout planes, and using the drift time it is possible to reconstruct every individual nuclear reaction in three dimensions (and with particle identification).…”

Section: Choosing the Right Experimental Approach To Match The Experimentioning

confidence: 99%

“…However, this problem is largely removed if it is possible to determine the precise point of interaction within the target. By turning the target into an active detector, designs such as MAYA [66] (shown in Figure 17) achieve this objective and hence can be used with the lowest beam intensities. In fact, for higher beam intensities it is usually necessary in this type of detector to place an electrostatic screen around the path of the beam itself.…”

Section: Choosing the Right Experimental Approach To Match The Experimentioning

confidence: 99%

What Can We Learn from Transfer, and How Is Best to Do It?

Catford

2014

The Euroschool on Exotic Beams, Vol. IV

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An overview of the experimental aspects of nucleon transfer reactions with radioactive beams is presented, aimed principally at a researcher who is beginning their work in this area. Whilst the physics motivation and the means of theoretical interpretation are briefly described, the emphasis is on the experimental techniques and the quantities that can be measured. General features of the reactions which affect experimental design are highlighted and explained. A range of experimental choices for performing the experiments is described, and the reasons for making the different choices are rationalised and discussed. It is often useful to detect gamma-rays from electromagnetic transitions in the final nucleus, both to improve the precision and resolution of the excitation energy measurements and to assist in the identification of the observed levels. Several aspects related to gamma-ray detection and angular correlations are therefore included. The emphasis is on single-nucleon transfer reactions, and mostly on (d,p) transfer to produce nuclei that are more neutron-rich, but there are also brief discussions of other types of transfer reactions induced by both light ions and heavy ions.

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MAYA, a gaseous active target

Cited by 47 publications

References 4 publications

Active targets for the study of nuclei far from stability

Active targets for the study of nuclei far from stability

Measurement of the Isoscalar Monopole Response in the Neutron-Rich NucleusNi68

What Can We Learn from Transfer, and How Is Best to Do It?

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