AUTHOR=Norbury John W. , Battistoni Giuseppe , Besuglow Judith , Bocchini Luca , Boscolo Daria , Botvina Alexander , Clowdsley Martha , de Wet Wouter , Durante Marco , Giraudo Martina , Haberer Thomas , Heilbronn Lawrence , Horst Felix , Krämer Michael , La Tessa Chiara , Luoni Francesca , Mairani Andrea , Muraro Silvia , Norman Ryan B. , Patera Vincenzo , Santin Giovanni , Schuy Christoph , Sihver Lembit , Slaba Tony C. , Sobolevsky Nikolai , Topi Albana , Weber Uli , Werneth Charles M. , Zeitlin Cary 

TITLE=Are Further Cross Section Measurements Necessary for Space Radiation Protection or Ion Therapy Applications? Helium Projectiles

JOURNAL=Frontiers in Physics

VOLUME=8

YEAR=2020

URL=https://www.frontiersin.org/journals/physics/articles/10.3389/fphy.2020.565954

DOI=10.3389/fphy.2020.565954

ISSN=2296-424X

ABSTRACT=<p>The helium (<inline-formula id="inf1"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msup><mml:mrow></mml:mrow><mml:mn>4</mml:mn></mml:msup></mml:mrow></mml:math></inline-formula>He) component of the primary particles in the galactic cosmic ray spectrum makes significant contributions to the total astronaut radiation exposure. <inline-formula id="inf2"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msup><mml:mrow></mml:mrow><mml:mn>4</mml:mn></mml:msup></mml:mrow></mml:math></inline-formula>He ions are also desirable for direct applications in ion therapy. They contribute smaller projectile fragmentation than carbon (<inline-formula id="inf3"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msup><mml:mrow></mml:mrow><mml:mrow><mml:mn>12</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math></inline-formula>C) ions and smaller lateral beam spreading than protons. Space radiation protection and ion therapy applications need reliable nuclear reaction models and transport codes for energetic particles in matter. Neutrons and light ions (<inline-formula id="inf4"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msup><mml:mrow></mml:mrow><mml:mn>1</mml:mn></mml:msup></mml:mrow></mml:math></inline-formula>H, <inline-formula id="inf5"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msup><mml:mrow></mml:mrow><mml:mn>2</mml:mn></mml:msup></mml:mrow></mml:math></inline-formula>H, <inline-formula id="inf6"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msup><mml:mrow></mml:mrow><mml:mn>3</mml:mn></mml:msup></mml:mrow></mml:math></inline-formula>H, <inline-formula id="inf7"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msup><mml:mrow></mml:mrow><mml:mn>3</mml:mn></mml:msup></mml:mrow></mml:math></inline-formula>He, and <inline-formula id="inf8"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msup><mml:mrow></mml:mrow><mml:mn>4</mml:mn></mml:msup></mml:mrow></mml:math></inline-formula>He) are the most important secondary particles produced in space radiation and ion therapy nuclear reactions; these particles penetrate deeply and make large contributions to dose equivalent. Since neutrons and light ions may scatter at large angles, double differential cross sections are required by transport codes that propagate radiation fields through radiation shielding and human tissue. This work will review the importance of <inline-formula id="inf9"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msup><mml:mrow></mml:mrow><mml:mn>4</mml:mn></mml:msup></mml:mrow></mml:math></inline-formula>He projectiles to space radiation and ion therapy, and outline the present status of neutron and light ion production cross section measurements and modeling, with recommendations for future needs.</p>