Energy-loss straggling of 2–10 MeV/u Kr ions in gases

Abstract

Abstract. Measurements have been performed on a time-of-flight setup at the Jyväskylä K130 cyclotron, aiming at energy-loss straggling of heavy ions in gases. Theoretical predictions based on recently developed theory as well as an empirical interpolation formula predict that straggling can be more than ten times higher than Bohr straggling in the MeV/u regime. Our measurements with up to 9.3 MeV/u Kr ions on He, N2, Ne and Kr targets confirm this feature. Our calculations show the relative contributions of linear straggling, bunching including packing, and charge exchange. Our results for stopping cross sections are compatible with values from the literature.

Electron correlations in the antiproton energy-loss distribution in He

“…For gas-phase targets only very few measurements are available [9][10][11]28]. Theoretical treatments, to date, rely on perturbation theory converging to the high-energy limit T B = 4πZ 2 p Z T e 2 for electronic straggling derived by Bohr from classical binary encounter scattering [2] of the projectile on Z T independent free electrons of the target atom.…”

Energy loss and straggling of MeV Si ions in gases

“…The energy profile of the ions after the gas cell is measured by the time-of-flight (TOF) technique ( Fig. 3) similar to our previous experiment (JYFL experiment A75) with Kr beam [9]. Because of the higher energy the pressure in the 241 mm long gas cell needed to be higher (up to 1000 mbar) for sufficient energy loss, and therefore used thin 200 nm silicon nitride membranes 3 as entrance and exit windows.…”

“…In order to provide more reliable experimental data for comparison with theory, we performed energy-loss straggling measurements using different ion beams (Si and Kr), energies and gas targets (He, N 2 , Ar, Ne and Kr), which were selected by the guidance of dedicated theoretical calculations [5]. The measurements with Kr beam have been published previously [9] with a reanalysis in [5]. We report here on the measurements with 28 Si beam in the energy range 0.5 − 12 MeV/u 2 performed at two accelerator facilities.…”

A simple timestamping data acquisition system for ToF-ERDA

“…The system has been applied for energy loss measurement of protons in liquid water [10], energyloss straggling measurements of Kr ions in gases [2] and, as described in chapter 4, for high-precision energy loss measurements using a calorimetric low-temperature detector.…”

“…Time-of-Flight Elastic Recoil Detection Analysis (ToF-ERDA) [1] and other similar Time-of-Flight (ToF) measurement set-ups, such as ToF-ToF [2] or ToF-E systems require a multi parameter data acquisition system capable of recording coincident ToF-and energy information. In the most simplest form a coincidence unit is used for generating a common gate signal for the pulse height ADCs associated with ToF and energy channels.…”