Experimental Setup for Irradiation of Cell Cultures at L2A2

Alberto Torralba,Michael Seimetz,José Benlliure,Miguel Elías Aguado-Barrera,Juan Pablo Rigla,Alicia Reija,Lidia Palenciano,Juan Peñas,Ana Vega,Camilo Ruiz,Juan José Llerena,Ramiro Contreras-Martínez

doi:10.3390/qubs6010010

Abstract

Laser–plasma proton sources and their applications to preclinical research has become a very active field of research in recent years. In addition to their small dimensions as compared to classical ion accelerators, they offer the possibility to study the biological effects of ultra-short particle bunches and the correspondingly high dose rates. We report on the design of an experimental setup for the irradiation of cell cultures at the L2A2 laboratory at the University of Santiago de Compostela, making use of a 1.2 J Ti: Sapphire laser with a 10 Hz repetition rate. Our setup comprises a proton energy separator consisting of two antiparallel magnetic fields realized by a set of permanent magnets. It allows for selecting a narrow energy window around an adaptable design value of 5 MeV out of the initially broad spectrum typical for Target Normal Sheath Acceleration (TNSA). At the same time, unwanted electrons and X-rays are segregated from the protons. This part of the setup is located inside the target vessel of the L2A2 laser. A subsequent vacuum flange sealed with a thin kapton window allows for particle passage to external sample irradiation. A combination of passive detector materials and real-time monitors is applied for measurement of the deposited radiation dose. A critical point of this interdisciplinary project is the manipulation of biological samples under well-controlled, sterile conditions. Cell cultures are prepared in sealed flasks with an ultra-thin entrance window and analysed at the nearby Fundación Pública Galega Medicina Xenómica and IDIS. The first trials will be centred at the quantification of DNA double-strand breaks as a function of radiation dose.

Highlights

We have recently developed an experimental setup for cell culture irradiation at the Laser Laboratory for Acceleration and Medical Applications (L2A2) at Santiago de Compostela, making use of the 1.2 J/35 fs Ti: Sapphire beam line
An experimental setup for the irradiation of cell cultures with laser-accelerated protons has been prepared at the 1.2 J pulsed laser beamline of L2A2
It comprises a pair of antiparallel magnetic dipole fields which allow for selecting a narrow range of particle energies from the initially broad spectral distribution typical for Target Normal Sheath Acceleration (TNSA)

Summary

Introduction

Several non-clinical accelerator facilities operating at high [4] or comparatively lower ion energies [5,6,7,8] have implemented beamlines for the controlled irradiation of biological samples. Several laser laboratories have implemented dedicated setups for the controlled irradiation of cell cultures (for a recent review, see [13]). In order to measure the applied dose, the energies of the protons at the sample surface and the particle fluence have to be known. This generally implies the necessity for selecting a narrow interval out of the initially broad ion spectra and for the implementation of suitable detectors.

Energy Selector

Particle Fluence Detectors

Cell Cultures

Findings

Conclusions and Outlook