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Nuclear Cross Section

Published: 2014/04/14

Channel: AK LECTURES

Nuclear Cross Section & Specific Activity of Radioactive Substance

Published: 2017/03/21

Channel: Priyanka Jain

Microscopic Cross Section Lesson

Published: 2014/03/03

Channel: STS Defence

Cross Section

Published: 2013/05/17

Channel: Jefferson Lab

Mod-01 Lec-30 Nuclear Reactions

Published: 2014/03/25

Channel: nptelhrd

Cross section (physics)

Published: 2016/01/22

Channel: WikiAudio

19: Scattering cross section

Published: 2012/11/14

Channel: NTNU openVideo

The collision cross-section explained

Published: 2013/03/08

Channel: Oxford Academic (Oxford University Press)

Cross section Meaning

Published: 2015/04/18

Channel: SDictionary

The Uranium 235 Chain Reaction*Physics Made Fun

Published: 2016/03/25

Channel: *29 INDIAN MILITARY INTELLIGENCE 29*

NMR of Paracetamol

Published: 2016/10/04

Channel: NUS Chem Emelyn Tan

The nuclear radius - A Level Physics

Published: 2013/06/26

Channel: DrPhysicsA

DOE CSGF 2014: Cross Section Spatial Discretization for Nuclear Engineering Calculations

Published: 2014/08/13

Channel: Krell Institute

The Nuclear Fuel Cycle and North Korea: Science Behind Nuclear Weapons

Published: 2015/03/06

Channel: Stanford CISAC - Security Matters

Lateral and cross section nuclear cycles of a Drosophila embryo

Published: 2017/05/22

Channel: reeveslab

The Standard Model (Michael Peskin) | Lecture 3

Published: 2014/10/20

Channel: LeonhardEuler1

Freeman Dyson - How the warm neutron principle works (113/157)

Published: 2016/09/05

Channel: Web of Stories

Theocharis Kosmas: Neutrino-nucleus cross sections in currently available energy ranges

Published: 2015/01/15

Channel: Instituto de Física Corpuscular (IFIC)

JSI TRIGA Reactor - Thermal neutron cross section

Published: 2013/06/04

Channel: triga JSI

Nuclear Fission and Neutron Induced Fission Cross Sections A Nuclear Energy Agency Nuclear Data Comm

Published: 2016/10/20

Channel: McTeodor

Barn (unit)

Published: 2014/11/04

Channel: Audiopedia

Mod-01 Lec-15 Low energy n-p scattering

Published: 2014/03/25

Channel: nptelhrd

Neutron Cross Section Curves Neutron Cross Sections Series Volume 2 v 2

Published: 2016/10/11

Channel: Mrs. Almaș

KCNRP | Session 2 – Interaction of Neutrons with Matter

Published: 2015/09/17

Channel: Nuclear and Plasma Sciences Society AlexSC

Fission cross section for thermal neutrons inside JSI TRIGA Mark II reactor

Published: 2013/11/05

Channel: triga JSI

Radiation Safety in Nuclear Energy Explorations 1962 Atomic Energy Commission-PHS

Published: 2015/03/24

Channel: Jeff Quitney

JSI TRIGA Reactor - Fast neutron cross-section

Published: 2013/06/04

Channel: triga JSI

Fission cross section for fast neutrons inside JSI TRIGA Mark II reactor

Published: 2013/11/05

Channel: triga JSI

3h57m40s21f Nuclear Cross-Sections - Big Dots and Small Dots - TR2016a

Published: 2017/05/13

Channel: Thorium Remix

JEE Physics- Q-value of a nuclear reaction

Published: 2013/03/04

Channel: XLClasses

Cross section of a fruit fly embryo

Published: 2011/01/29

Channel: thedu01

Uranium Goes Critical english documentary Part 2

Published: 2013/10/15

Channel: Nicole Hergens

Fission cross section for epithemral neutrons inside JSI TRIGA Mark II reactor

Published: 2013/11/05

Channel: triga JSI

Aneutronic Nuclear Fusion Reactor + Engine Proposal

Published: 2013/05/31

Channel: Muon Ray

Nuclear Fusion 500 Terawatt Laser at the National Ignition Facility

Published: 2012/07/16

Channel: Muon Ray

第01講 Introduction to Nuclear Safety (A)

Published: 2013/04/08

Channel: NTHUOCW

Thermal n-gamma cross-section in JSI TRIGA reactor

Published: 2014/08/21

Channel: triga JSI

Mod-01 Lec-14 Scattering of nucleons

Published: 2014/03/25

Channel: nptelhrd

IEEE NPSS AlexSC | An Overview of Nuclear Reactors Calculations - Introduction

Published: 2017/05/20

Channel: Nuclear and Plasma Sciences Society AlexSC

Railway Tunnel with China's Biggest Cross Section Completed in NW China

Published: 2016/06/01

Channel: CCTV+

第10講 Neutron Attenuation (A)

Published: 2013/01/11

Channel: NTHUOCW

Freeman Dyson - Samarium 149 proves the world is so rich in detail (111/157)

Published: 2016/09/05

Channel: Web of Stories

Epithermal n-gamma cross-section in JSI TRIGA reactor

Published: 2014/08/21

Channel: triga JSI

Dimitrios Papoulias: Non-Standard Interactions in Nuclear Physics

Published: 2014/11/20

Channel: Instituto de Física Corpuscular (IFIC)

4h24m46s17f Xenon Most Common Fission Product - Absorbs Neutrons - Kills Fission - TR2016a

Published: 2017/05/14

Channel: Thorium Remix

Cross section of a fruit fly embryo

Published: 2012/02/16

Channel: reeveslab

第11講 Neutron Flax (A)

Published: 2013/01/11

Channel: NTHUOCW

Lovejoy's Nuclear War (1975)

Published: 2016/03/15

Channel: ZinnEdProject

第24講 Two-Group Calculation of Neutron Moderation (B)

Published: 2013/01/11

Channel: NTHUOCW

Nuclear Security: LECTURE 5 Prof. van Bibber

Published: 2017/02/28

Channel: NSSC - Nuclear Science and Security Consortium

From Wikipedia, the free encyclopedia

The **nuclear cross section** of a nucleus is used to characterize the probability that a nuclear reaction will occur. The concept of a nuclear cross section can be quantified physically in terms of "characteristic area" where a larger area means a larger probability of interaction. The standard unit for measuring a nuclear cross section (denoted as σ) is the barn, which is equal to 10^{−28} m² or 10^{−24} cm². Cross sections can be measured for all possible interaction processes together, in which case they are called total cross sections, or for specific processes, distinguishing elastic scattering and inelastic scattering; of the latter, amongst neutron cross sections the absorption cross sections are of particular interest.

In nuclear physics it is conventional to consider the impinging particles as point particles having negligible diameter. Cross sections can be computed for any sort of process, such as capture scattering, production of neutrons, etc. In many cases, the number of particles emitted or scattered in nuclear processes is not measured directly; one merely measures the attenuation produced in a parallel beam of incident particles by the interposition of a known thickness of a particular material. The cross section obtained in this way is called the total cross section and is usually denoted by a σ or σ_{T}.

Typical nuclear radii are of the order 10^{−14} m. Assuming spherical shape, we therefore expect the cross sections for nuclear reactions to be of the order of π*r* ² or 10^{−28} m² (i.e. 1 barn). Observed cross sections vary enormously - for example, slow neutrons absorbed by the (n, ) reaction show a cross section much higher than 1,000 barns in some cases (boron-10, cadmium-113, and xenon-135), while the cross sections for transmutations by gamma-ray absorption are in the region of 0.001 barn.

Nuclear cross sections are used in determining the nuclear reaction rate, and are governed by the reaction rate equation for a particular set of particles (usually viewed as a "beam and target" thought experiment where one particle or nucleus is the "target" [typically at rest] and the other is treated as a "beam" [projectile with a given energy]).

For neutron interactions incident upon a thin sheet of material (ideally made of a single type of isotope), the nuclear reaction rate equation is written as:

where:

- : number of reactions of type x, units: [1/time/volume]
- : beam flux, units: [1/area/time]
- : microscopic cross section for reaction , units: [area] (usually barns or cm
^{2}). - : density of atoms in the target in units of [1/volume]
- : macroscopic cross-section [1/length]

Types of reactions frequently encountered are *s*: scattering, : radiative capture, *a*: absorption (radiative capture belongs to this type), *f*: fission, the corresponding notation for cross-sections being: , , , etc. A special case is the total cross-section , which gives the probability of a neutron to undergo any sort of reaction ().

Formally, the equation above *defines* the macroscopic neutron cross-section (for reaction x) as the proportionality constant between a neutron flux incident on a (thin) piece of material and the number of reactions that occur (per unit volume) in that material. The distinction between macroscopic and microscopic cross-section is that the former is a property of a specific lump of material (with its density), while the latter is an intrinsic property of a type of nuclei.

This article includes a list of references, but its sources remain unclear because it has insufficient inline citations. (December 2009) (Learn how and when to remove this template message) |

*Nuclear Reactor Analysis*by James J. Duderstadt and Louis J. Hamilton -*Published by John Wiley & Sons, Inc.*- Perkins, Donald H. (1999).
*Introduction to High Energy Physics*. Cambridge University Press. ISBN 0-521-62196-8. - Mubarakmand, Samar; Masud Ahmad; M. Anwar; M.S. Chaudhry (1977). "Cross-section measurements with a neutron generator".
*The Nucleus*. Nilore, Islamabad: PINSTECH.**42**(1-2): 115–185.

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