Calorimetric low temperature detectors for heavy ion physics and their application in nuclear and atomic physics

Abstract

The concept of a relatively new type of energy sensitive detectors, namely calorimetric low temperature detectors, which measure the temperature rise of an absorber due to the impact of an energetic particle or photon, is displayed, and its basic properties and its advantage over conventional detector schemes is discussed. Due to the low operating temperature, the impact of a microscopic particle or photon affects the properties of a macroscopic piece of matter (absorber) and therefore allows to measure the incident energy with high sensitivity and with high resolution. The present article will focus on the application of such detectors in the field of heavy ion physics, and it will be demonstrated that this type of detector bears a large potential as a powerful tool for many fields of nuclear and atomic heavy ion physics. The design and construction of calorimetric low temperature detectors for the detection of heavy ions in the energy range of $0.05-360\mathrm{MeV/u}$, operated at temperatures around $1-2K$, and of hard x-rays in the energy range of $50-100\mathrm{keV}$, operated at temperatures of $50-100\mathrm{mK}$, is displayed and examples of the performance are presented. The excellent energy resolution of the order of $\Delta E/E=1-5\times 10^{-3}$ for various ion species, ranging from ${}^4\mathrm{He}$ to ${}^{238}U$, and the linearity of the energy response without any indication of pulse height defects, and the obtained mass resolution down to $\Delta m=1.3\mathrm{amu}$ for heaviest ions like ${}^{238}U$, which represent a considerable improvement as compared to conventional heavy ion detectors based on ionization, have already allowed for various first applications in nuclear heavy ion physics. As prominent examples, the precise determination of isotopic yield distributions of fission fragments from thermal neutron induced fission of ${}^{238}U$ and ${}^{239,241}\mathrm{Pu}$, the precise determination of electronic stopping powers of various ions in various absorbers down to energies far below the Bragg peak, and the trace analysis of rare isotopes in accelerator mass spectroscopy, will be discussed. Future perspectives for further applications for high resolution nuclear spectroscopy, and the direct in-flight mass identification of heavy ions for the identification of superheavy elements and of reaction products from reactions with radioactive beams in inverse kinematics, and others, are also displayed. Concerning the field of atomic physics, where energy resolutions down to $\Delta E=22\mathrm{eV}$ for 60 keV x-rays have been obtained, the application of calorimetric low temperature detectors for Lamb shift measurements on hydrogen-like heavy ions, and various other applications, will be discussed.