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Neutron Hunt. Project presentation b y Andreas Nrgrd Larsen, Copenhagen University. Intro. W here : CMS What : Medipix detectors . Why : Online neutron detection gives better knowledge of neutron flux . So we can : A djust simulations of the radiation in the CMS cavern . - PowerPoint PPT Presentation

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Project presentation

Neutron HuntProject presentation by Andreas Nrgrd Larsen,Copenhagen University

Neutron HuntBack in the 30th the neutron was the exciting new particle, that every phycisist were talking about. It was just as exciting as the Higgs boson is today. Nowadays it is so well-known that it seems a bit grey and boring. Who is interested in neutrons today?In 10 minutes you will know the answer to that question and on top of that you will know how to hunt these neutrons. 1IntroWhere: CMSWhat: Medipix detectors.Why : Online neutron detection gives better knowledge of neutron flux. So we can:Adjust simulations of the radiation in the CMS cavern.Provide knowledge about the risk of Single Event Upset (SEU). Give better understanding and better predictions2Single Event UpsetChange bit in electrical device: 1 0Example: Failure in electronics in CNGS (CERN Neutrinos to Gran Sasso) in 2007

Vice versa3MedipixSilicon: measure charged particlesLow cross section for direct neutron-Si interaction generating charged particles, therefore: Conversion layers!

Picture from: www.scienceinschool.orgNeutrons can interact directly with silicon, but rarely do. Therefore: conversion layers.

(PCB: Printet Circuit Board).

4Conversion layers

Picture from: D. Turecek, T. Holy, S. Pospicil, Z. Vykydal, Elsevier ;Nuclear Instruments and Methods in Physics Research A 633 (2011) S45S47

Conversion layersTodays focus: Polyethylene, PEEffective for fast neutrons, i.e. from 2 to 50 MeV.

Bring suncream6PolyethyleneElastic scattering

The process of kicking out protons has a high cross section for fast neutronsProtons are charged!

Bring suncream7PolyethyleneElastic scattering

The process of kicking out protons has a high cross section for fast neutronsProtons are charged!

Bring suncream8Effect of Conversion layers- simulation with FLUKA

Energy deposited in Silicon is proportional to signal measured with the detector9

Thickness of PE conversion layerThickness by now: 1300 m10

Density of PE conversion layerThickness is 1.3 mmThickness by now: 1300 m11

Neutrons in the CMS

Simulated data from this point

Not only fast neutrons, so other conversion layers are necessary. 12I hope you knowWhy neutrons are still interesting.How to hunt them.Thank you for your attention!Special thanks to: Dieter Loterman (focus data)Sophie Mallows (FLUKA expert 1)Mouritz Guthoff (FLUKA expert 2)Slawomir Konrad Tadeja (Computer expert)Arkady Lokhovitskiy (supervisor)Alan James Bell (supervisor)