title: Enhanced production of low energy electrons by alpha particle impact.
abstract: Radiation damage to living tissue stems not only from primary ionizing particles but to a substantial fraction from the dissociative attachment of secondary electrons with energies below the ionization threshold. We show that the emission yield of those low energy electrons increases dramatically in ion-atom collisions depending on whether or not the target atoms are isolated or embedded in an environment. Only when the atom that has been ionized and excited by the primary particle impact is in immediate proximity of another atom is a fragmentation route known as interatomic Coulombic decay (ICD) enabled. This leads to the emission of a low energy electron. Over the past decade ICD was explored in several experiments following photoionization. Most recent results show its observation even in water clusters. Here we show the quantitative role of ICD for the production of low energy electrons by ion impact, thus approaching a scenario closer to that of radiation damage by alpha particles: We choose ion energies on the maximum of the Bragg peak where energy is most efficiently deposited in tissue. We compare the electron production after colliding He(+) ions on isolated Ne atoms and on Ne dimers (Ne(2)). In the latter case the Ne atom impacted is surrounded by a most simple environment already opening ICD as a deexcitation channel. As a consequence, we find a dramatically enhanced low energy electron yield. The results suggest that ICD may have a significant influence on cell survival after exposure to ionizing radiation.
authors: Goethe-Universität Frankfurt, Institut für Kernphysik, Frankfurt, Germany. kim@atom.uni-frankfurt.de
authors: Hong-Keun
authors: HK
authors: Kim
authors: Jasmin
authors: J
authors: Titze
authors: Markus
authors: M
authors: Schöffler
authors: Florian
authors: F
authors: Trinter
authors: Markus
authors: M
authors: Waitz
authors: Jörg
authors: J
authors: Voigtsberger
authors: Hendrik
authors: H
authors: Sann
authors: Moritz
authors: M
authors: Meckel
authors: Christian
authors: C
authors: Stuck
authors: Ute
authors: U
authors: Lenz
authors: Matthias
authors: M
authors: Odenweller
authors: Nadine
authors: N
authors: Neumann
authors: Sven
authors: S
authors: Schössler
authors: Klaus
authors: K
authors: Ullmann-Pfleger
authors: Birte
authors: B
authors: Ulrich
authors: Rui Costa
authors: RC
authors: Fraga
authors: Nikos
authors: N
authors: Petridis
authors: Daniel
authors: D
authors: Metz
authors: Annika
authors: A
authors: Jung
authors: Robert
authors: R
authors: Grisenti
authors: Achim
authors: A
authors: Czasch
authors: Ottmar
authors: O
authors: Jagutzki
authors: Lothar
authors: L
authors: Schmidt
authors: Till
authors: T
authors: Jahnke
authors: Horst
authors: H
authors: Schmidt-Böcking
authors: Reinhard
authors: R
authors: Dörner
mesh_terms: D000512:Alpha Particles; D002470:Cell Survival / Q000528:radiation effects*; D004583:Electrons; D006371:Helium / Q000737:chemistry; D009356:Neon / Q000737:chemistry; D013057:Spectrum Analysis
chemical_list: D006371:Helium; D009356:Neon