Eur. Phys. J. A (2018) 54: 96
https://doi.org/10.1140/epja/i2018-12531-5

Regular Article - Experimental Physics

Understanding the thermometry of hot nuclei from the energy spectra of light charged particles

¹ Normandie Univ, ENSICAEN, UNICAEN, CNRS/IN2P3, LPC Caen, F-14000, Caen, France
² Institut de Physique Nucléaire, CNRS/IN2P3, Univ. Paris-Sud, Université Paris-Saclay, F-91406, Orsay Cedex, France
³ Grand Accélérateur National d’Ions Lourds (GANIL), CEA/DRF-CNRS/IN2P3, Bvd. Henri Becquerel, 14076, Caen, France
⁴ Dipartimento di Fisica “E. Pancini” and Sezione INFN, Università di Napoli “Federico II”, I-80126, Napoli, Italy
⁵ Conservatoire National des Arts et Métiers, F-75141, Paris Cedex 03, France
⁶ Dipartimento di Fisica, Universitá di Firenze, via G. Sansone 1, I-50019, Sesto Fiorentino (FI), Italy
⁷ IPNL/IN2P3 et Université de Lyon/Université Claude Bernard Lyon 1, 43 Bd du 11 novembre 1918, F69622, Villeurbanne Cedex, France
⁸ INFN - Sezione Catania, via Santa Sofia 64, 95123, Catania, Italy
⁹ Ecole des Applications Militaires de l’Energie Atomique, BP 19 50115, Cherbourg Armées, France
¹⁰ CEA, DAM, DIF, F-91297, Arpajon, France
¹¹ Hulubei National Institute for R & D in Physics and Nuclear Engineering (IFIN-HH), P.O.BOX MG-6, RO-76900, Bucharest-Màgurele, Romania
¹² Laboratoire de Physique Nucléaire, Université Laval, G1K 7P4, Québec, Canada

^* e-mail: vient@lpccaen.in2p3.fr

Received: 13 October 2017
Accepted: 7 May 2018
Published online: 15 June 2018

Abstract

In the Fermi energy domain, the temperature of hot nuclei can be determined using the energy spectra of evaporated light charged particles. But this method of measurement is not without difficulties both theoretical and experimental. The present study aims to disentangle the respective influences of different factors on the quality of this measurement: the physics, the detection (a detector array such as INDRA) and the experimental procedure. This analysis demonstrates the possibility of determining from an energy spectrum, with an accuracy of about 10%, the true apparent temperature felt by a given type of particle emitted from a hot nucleus. This temperature allows to deduce the initial temperature using an appropriate method. However, three conditions are necessary: a perfect particle detector, important statistics and very weak secondary emissions. According to the GEMINI event generator, for hot intermediate mass nuclei, only deuterons and tritons could meet these conditions. In this case the determination may be better than 15%. With a realistic experimental device, insufficient angular resolution and topological distortions, caused by detection, can distort spectra to the point where it is very difficult to determine the apparent temperature correctly. Experimental reconstruction of the moving frame of the hot nucleus can also be responsible for this deterioration.