Speaker
Description
Exclusive study of Pre-Equilibrium Emission of Alpha Particles in Alpha Induced Reactions at Moderate Excitation Energy
Avinash Agarwal1*, and Manoj Kumar Sharma2
1 Department of Physics, Bareilly College, Bareilly, MJPR University, Bareilly – 243001 INDIA
2 Department of Physics, Shri Varshney College, Aligarh – 202 001 INDIA
* Email: avibcb@gmail.com
During the past few decades, the mechanism of pre-compound (PCN) emission has
been a topic of fundamental interest in α-particle induced reactions at low and intermediate
energies. Earlier many of the theoretical and experimental studies have triggered the
observation of such phenomenon at relatively higher energies. Recent studies showing the
observations of PCN emission even at low incident energies where evaporation process
dominates, have renewed interest to carry out further research in the aforesaid reaction
mechanism [1-4]. In the present work excitation functions for (,n) and (,xn) reaction channels for light, medium and heavy mass targets e.g., 55Mn, 89Y and 169Tm have been analysed with the available reaction model codes ALICE91 [5], PACE4 [6], EMPIRE3.2 [7], Talys1.95 [8] and COMPLET [9]. All these models have been extensively employed to optimize global set of input parameters available with in the codes for reproduction of experimental data available in literature for the said targets.
From the present study it is observed that for (,n) channels all the model codes satisfactorily reproduced the experimental excitation functions for optimized set of input parameters while the shallowness of dips (valleys) in the experimental excitation functions of the reactions (,xn) clearly indicates that the alpha particle might be emitted in the pre-equilibrium phase. The emission of an alpha particle in the pre-equilibrium phase is not included in the other nuclear models except COMPLET. This is the reason for steep valleys in the theoretical curves obtained via other codes as opposed to the shallow dips observed in the experimental excitation functions. The alpha particle emission is treated as an evaporation process in the codes, while COMPLET model gives a better agreement, giving a shallow valley region indicating the inclusion of pre-equilibrium alpha emission in the model.
References:
1. M. K. Sharma et. al., Eur. Phys. J. A 56, 247 (2020)
2. M. K. Sharma et.al., Phys. Rev. C 99 014608 (2019)
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4. Avinash Agarwal et. al., Phys. Rev. C. 65 034605 (2002)
5. M. Blann et al., Phys. Rev. C 28, 1475 (1983)., M. Blann, LLNL Report No. UCID 19614, (1982)
6. A. Gavron, Phys. Rev. C 21, 230 (1980).
7. M. Herman et. al, Nucl. Data Sheets 108, 2655 (2007).
8. A.J. Koning et. al., Nuclear Data Sheets 113 2841 (2012)
9. J. Ernst et.al., Z Phys. A. 333 45 (1989)
