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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

Cross Section

Published: 2013/05/17

Channel: Jefferson Lab

Microscopic Cross Section Lesson

Published: 2014/03/03

Channel: STS Defence

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

Cross section Meaning

Published: 2015/04/18

Channel: SDictionary

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

Published: 2014/08/13

Channel: Krell Institute

The collision cross-section explained

Published: 2013/03/08

Channel: Oxford Academic (Oxford University Press)

The Uranium 235 Chain Reaction*Physics Made Fun

Published: 2016/03/25

Channel: *29 INDIAN MILITARY INTELLIGENCE 29*

The nuclear radius - A Level Physics

Published: 2013/06/26

Channel: DrPhysicsA

Collision Cross Section Measurements for Food & Environmental Analysis

Published: 2015/12/03

Channel: Waters Corporation

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

Published: 2015/03/06

Channel: Stanford CISAC - Security Matters

5-energy of a nuclear reaction

Published: 2013/07/29

Channel: Reed Jeffrey

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

Published: 2014/03/25

Channel: nptelhrd

Lateral and cross section nuclear cycles of a Drosophila embryo

Published: 2017/05/22

Channel: reeveslab

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

Published: 2016/10/20

Channel: McTeodor

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

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

Published: 2013/11/05

Channel: triga JSI

Barn (unit)

Published: 2014/11/04

Channel: Audiopedia

Lecture 24 Nuclear Reactions, Compound Nuclear Reactions, Direct Reactions

Published: 2015/03/05

Channel: ThePhysicsToday

Nuclear Scattering & Spin

Published: 2014/07/25

Channel: DrPhysicsA

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

Published: 2016/10/11

Channel: Mrs. Almaș

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

Published: 2017/05/13

Channel: Thorium Remix

a cross section

Published: 2014/07/11

Channel: Alejandro Salas

Technology Talks (Fundamentals): Why is it useful to measure collision cross section (CCS)?

Published: 2016/09/13

Channel: Waters Corporation

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

KCNRP | Session 2 – Interaction of Neutrons with Matter

Published: 2015/09/17

Channel: Nuclear and Plasma Sciences Society AlexSC

Cross Sections

Published: 2013/04/13

Channel: MathMeij

Cross section of a fruit fly embryo

Published: 2012/02/16

Channel: reeveslab

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

Published: 2013/11/05

Channel: triga JSI

Nuclear Physics - Nuclear Reactions

Published: 2013/08/14

Channel: The New Jersey Center for Teaching and Learning

Cross section of a fruit fly embryo

Published: 2011/01/29

Channel: thedu01

Mod-01 Lec-14 Scattering of nucleons

Published: 2014/03/25

Channel: nptelhrd

Elastic Neutron Scattering

Published: 2014/09/04

Channel: Jan Leen Kloosterman

UNM Phys 531 2011 Lec23 Saturation, photon scattering, cross sections

Published: 2016/04/19

Channel: CosmoLearning

Particle Physics (31 of 41) What is a Photon? 15. Mie Scattering - Radar Cross Section

Published: 2015/05/27

Channel: Michel van Biezen

Aneutronic Nuclear Fusion Reactor + Engine Proposal

Published: 2013/05/31

Channel: Muon Ray

Dimitrios Papoulias: Non-Standard Interactions in Nuclear Physics

Published: 2014/11/20

Channel: Instituto de Física Corpuscular (IFIC)

20: Scattering cross section - Part 2

Published: 2012/11/14

Channel: NTNU openVideo

The Standard Model (Michael Peskin) | Lecture 3

Published: 2014/10/20

Channel: LeonhardEuler1

1- Understanding Total Cross Section (Electron Impact)

Published: 2016/10/02

Channel: Iff CSIC-MADRID

DOE CSGF 2016: Discretization by Machine Learning (and its Application to Nuclear Reactor Simulat...

Published: 2016/08/23

Channel: Krell Institute

Nuclear Fusion: GCSE revision

Published: 2014/02/03

Channel: DrPhysicsA

Nuclear Reactions and Radiation

Published: 2016/10/24

Channel: Ultimate Engineering

Nuclear Reactions and Reaction Energy

Published: 2014/04/13

Channel: AK LECTURES

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

Published: 2016/06/01

Channel: CCTV+

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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