:We study the breakdown voltage under low pressure for N2, CO2 gases of with a magnetic field to the electrode of iron and aluminum with diameter (8.8cm) cm and distance separation between them is (3cm). by using Passion curve, we measur less effort collapsed, and we notice that less effort is linked to the collapse of a function held cities and when the magnetic field will be reduced to shed breakdown voltage. Since the breakdown voltage for CO2 is greater than breakdown voltage N2. Through curved Passion was calculated (훾) and when to shed the magnetic field will increase in value
Jack Huang interned at AFRL/RQQE Energy Sciences Facility, where he studied gas breakdown and Paschen's Law under Dr. Steve Adams and others. His project involved collecting experimental data on the breakdown voltage of argon gas between electrode discs at varying pressures and distances. The data showed some agreement with Paschen's theoretical curve at lower pressure-distance values but diverged at higher values. Improving the computer model of gas breakdown and automating data collection were next steps. Huang gained experience in plasma physics research and appreciated the opportunity to contribute to an ongoing project.
The document discusses dielectric breakdown in gases. It explains the ionization processes that cause gas breakdown, including collision ionization, photoionization, and secondary ionization from positive ions and photons. Townsend's theory of gas breakdown is described, including the primary and secondary ionization coefficients α and γ. The Townsend breakdown criterion is given as γ(eαd - 1) = 1. Examples are provided to calculate α from experimental data. Factors that influence gas breakdown voltage are also discussed.
The document presents an analytical approach to estimate the range of alpha particles emitted from radon gas. It discusses the stopping power and range of charged particles as they pass through matter. Equations from Bohr and Bethe are provided to calculate stopping power. The results of simulations using SRIM2013 software to calculate alpha particle range and detection probabilities in air are presented and compared to previous SRIM versions. Tables and figures show trends in stopping power and range as alpha energy increases.
Welcome to PosiTron.
After the introductory slides, We are uploading the 1st content i.e. Charge to Mass Ratio of Electrons.
Please provide your valuable feedback. It will help us to improve more. If you have any queries do feel free to contact us.
Thank you,
Team PosiTron
Electrostatic fields and field stress controlvhasmukh96
This document discusses high voltage engineering and focuses on electric field distributions. It covers fields in homogeneous insulating materials like gases, fields in multi-dielectric materials, and numerical methods for solving field problems like the Finite Element Method. Specific topics include uniform fields, coaxial cylindrical and spherical fields, fields between spheres, and how conducting particles can distort fields. Fields in multi-layer dielectrics address configurations, dielectric refraction, and using screens to control stress.
Ph8253 physics for electronics engineeringSindiaIsac
1) The document discusses conducting materials and their properties. It describes how metals have high electrical conductivity due to free electrons. Current density is defined as the current per unit area.
2) Conducting materials are classified as zero resistive, low resistive, or high resistive based on their conductivity. Zero resistive materials conduct electricity with almost zero resistance below a transition temperature. Low and high resistive materials are used for conductors and resistors.
3) The classical free electron theory and quantum free electron theory are discussed as ways to explain electrical conductivity in metals based on their electronic structure and behavior of free electrons.
This document discusses different types of electron emission from metal surfaces. Thermionic emission occurs when heat is applied to a metal, increasing the kinetic energy of electrons and allowing them to overcome the surface barrier. Common thermionic emitters discussed are tungsten, thoriated tungsten, and oxide coatings, with their respective work functions and operating temperatures listed. The Richardson-Dushman equation describes how emission current density increases exponentially with temperature but depends on the work function of the emitter material.
The document discusses electrical breakdown in gases. It explains that gases are commonly used as dielectric mediums in electrical apparatus due to their insulating properties. However, when high voltages are applied, electrical breakdown can occur through ionization. The Townsend theory and streamer theory are presented as explanations for the breakdown mechanism under different conditions. Collision processes, mobility of ions and electrons, diffusion, and mean free path are also discussed. The document further explains the ionization process and Townsend's criteria for electrical breakdown in gases.
Jack Huang interned at AFRL/RQQE Energy Sciences Facility, where he studied gas breakdown and Paschen's Law under Dr. Steve Adams and others. His project involved collecting experimental data on the breakdown voltage of argon gas between electrode discs at varying pressures and distances. The data showed some agreement with Paschen's theoretical curve at lower pressure-distance values but diverged at higher values. Improving the computer model of gas breakdown and automating data collection were next steps. Huang gained experience in plasma physics research and appreciated the opportunity to contribute to an ongoing project.
The document discusses dielectric breakdown in gases. It explains the ionization processes that cause gas breakdown, including collision ionization, photoionization, and secondary ionization from positive ions and photons. Townsend's theory of gas breakdown is described, including the primary and secondary ionization coefficients α and γ. The Townsend breakdown criterion is given as γ(eαd - 1) = 1. Examples are provided to calculate α from experimental data. Factors that influence gas breakdown voltage are also discussed.
The document presents an analytical approach to estimate the range of alpha particles emitted from radon gas. It discusses the stopping power and range of charged particles as they pass through matter. Equations from Bohr and Bethe are provided to calculate stopping power. The results of simulations using SRIM2013 software to calculate alpha particle range and detection probabilities in air are presented and compared to previous SRIM versions. Tables and figures show trends in stopping power and range as alpha energy increases.
Welcome to PosiTron.
After the introductory slides, We are uploading the 1st content i.e. Charge to Mass Ratio of Electrons.
Please provide your valuable feedback. It will help us to improve more. If you have any queries do feel free to contact us.
Thank you,
Team PosiTron
Electrostatic fields and field stress controlvhasmukh96
This document discusses high voltage engineering and focuses on electric field distributions. It covers fields in homogeneous insulating materials like gases, fields in multi-dielectric materials, and numerical methods for solving field problems like the Finite Element Method. Specific topics include uniform fields, coaxial cylindrical and spherical fields, fields between spheres, and how conducting particles can distort fields. Fields in multi-layer dielectrics address configurations, dielectric refraction, and using screens to control stress.
Ph8253 physics for electronics engineeringSindiaIsac
1) The document discusses conducting materials and their properties. It describes how metals have high electrical conductivity due to free electrons. Current density is defined as the current per unit area.
2) Conducting materials are classified as zero resistive, low resistive, or high resistive based on their conductivity. Zero resistive materials conduct electricity with almost zero resistance below a transition temperature. Low and high resistive materials are used for conductors and resistors.
3) The classical free electron theory and quantum free electron theory are discussed as ways to explain electrical conductivity in metals based on their electronic structure and behavior of free electrons.
This document discusses different types of electron emission from metal surfaces. Thermionic emission occurs when heat is applied to a metal, increasing the kinetic energy of electrons and allowing them to overcome the surface barrier. Common thermionic emitters discussed are tungsten, thoriated tungsten, and oxide coatings, with their respective work functions and operating temperatures listed. The Richardson-Dushman equation describes how emission current density increases exponentially with temperature but depends on the work function of the emitter material.
The document discusses electrical breakdown in gases. It explains that gases are commonly used as dielectric mediums in electrical apparatus due to their insulating properties. However, when high voltages are applied, electrical breakdown can occur through ionization. The Townsend theory and streamer theory are presented as explanations for the breakdown mechanism under different conditions. Collision processes, mobility of ions and electrons, diffusion, and mean free path are also discussed. The document further explains the ionization process and Townsend's criteria for electrical breakdown in gases.
This document provides information about a High Voltage Engineering course, including:
- The examination scheme which includes marks for internal and end semester exams, as well as term work.
- An overview of the 6 course units which cover topics like breakdown in gases and liquids, generation of high voltages, measurement techniques, and testing of electrical apparatus.
- Detailed content on Unit 1 related to breakdown in gases, including Townsend's theory, ionization processes, and the limitations of Townsend's theory.
The document summarizes various cathode processes and decay processes involved in electrical breakdown in gases. It describes four main ways electrons can be emitted from a cathode surface: 1) photoelectric emission through photon bombardment, 2) electron emission through positive ion or excited atom impact, 3) thermionic emission through heating the cathode, and 4) field emission through very strong electric fields lowering the work function. It also discusses two major decay processes: 1) deionization through recombination of positive and negative ions, and 2) deionization through attachment of free electrons to form stable negative ions, especially in electronegative gases.
This document provides a summary of key concepts regarding electrical breakdown and conduction in gases:
- Gases can act as insulating or conducting media depending on the applied voltage. Low voltages allow small currents, while higher voltages cause electrical breakdown through ionization processes.
- Breakdown occurs through the formation of a conductive spark between electrodes. It involves transitions from non-sustaining to self-sustaining discharges.
- Ionization processes like collisional ionization and photoionization generate free electrons and ions, leading to current growth. Secondary processes like positive ion bombardment and photon emission further sustain the discharge.
- The Townsend theory and streamer theory describe the mechanisms of breakdown under different conditions involving
1. The document describes an experiment to measure the charge-to-mass ratio of electrons using Thomson's cathode ray tube.
2. Two methods are used: 1) null deflection where electric and magnetic fields cancel each other out, and 2) deflection by a magnetic field alone where the radius of curvature is measured.
3. Equations are derived relating the experimental measurements to the charge-to-mass ratio. The results from both methods are within 2% of the accepted value, validating Thomson's original discovery of the electron.
This document discusses Townsend's theory of gas breakdown. It explains that Townsend's theory describes how ionization occurs through collisions between gas molecules and electrons, leading to an avalanche effect. The key points are:
1) Townsend developed equations to model how the number and current of electrons increase exponentially with distance through a gas, depending on factors like the ionization coefficient and secondary ionization processes.
2) His theory can predict the breakdown voltage and distance at which a spark will occur due to a self-sustaining avalanche buildup.
3) The theory applies best at low gas pressures, and needs modifying for electronegative gases that can attach electrons through additional processes.
Townsend ’s theory
Introduction
Ionization by collision
Townsend’s current growth equation
Current Growth in the Presence of Secondary Processes
Townsend’s secondary ionization coefficient
Townsend’s Criterion for Breakdown
Breakdown in Electronegative Gases
This document provides a question bank on the topic of engineering physics for a bachelor's degree program. It includes 70 questions across three sections - short answer, descriptive, and problems. The short answer section contains multiple choice and short response questions testing concepts like band structure of materials, Hall effect, semiconductors, and superconductors. The descriptive section asks students to explain key theories and differentiate between material types. The problems section provides calculations testing conductivity, mobility, drift velocity, and other quantitative applications of the theoretical concepts.
This document discusses the history and development of high voltage engineering. It begins with early experiments with static electricity by ancient Greeks. Key figures who contributed include Franklin, Faraday, Tesla, and Edison. Faraday's law established that a magnetic field can induce current in a wire. Advances allowed longer distance power transmission. Challenges included developing high voltage insulation. Numerical methods like finite element analysis are now used to model electric field distributions in complex high voltage components.
1. This document summarizes an experiment on determining the heat of reaction using a calorimeter. Electrical energy was passed through a coil in the calorimeter, heating the water and increasing its temperature.
2. The experiment aimed to determine the equivalence between electrical/mechanical energy and heat energy. Measurements of voltage, current, water mass, and temperature changes were recorded over multiple trials.
3. The results showed that a larger voltage and current produced a greater increase in temperature over time. This supported the conclusion that a larger amount of electrical energy input leads to a larger amount of heat energy generated.
This document contains an assignment submission that discusses the conductivity of different materials. It begins with an introduction that defines conductors, semiconductors, and insulators based on their conductivity. It then covers energy bands and band diagrams, explaining how they relate to conductivity. Next, it discusses how band diagrams can be used to understand conductivity differences between materials. Finally, it addresses how conductivity in semiconductors varies with temperature, showing that it increases exponentially as temperature rises due to more electrons entering the conduction band. The assignment provides numerical examples and calculations to support the concepts.
(Thompson's Method) Electron's charge to mass ratio. ..(manish & jatin) ...pptJatinMahato1
1. The document describes an experiment to determine the charge-to-mass ratio (e/m) of electrons using Thompson's method.
2. The apparatus used includes an electron gun, e/m tube filled with low-pressure helium gas, and Helmholtz coils to produce a magnetic field. Electrons are accelerated and their path is deflected by the magnetic field.
3. By measuring the diameter of the electron path for different accelerating voltages and magnetic field strengths, the value of e/m is calculated using the equation e/m = 8V/B2d2. The experimentally obtained value of 1.729 × 1011 C/kg agrees well with the accepted value of
This slide set corresponds to the MaterialsConcepts YouTube video "Muddiest Point- Electronic Properties I. Here's the link:
https://www.youtube.com/watch?v=BY8ZPobU8B0
To study the vocab used in this video, visit this site:
http://quizlet.com/24383440/71-electronic-properties-i-conductors-insulators-semiconductors-flash-cards/
This work was supported by NSF Grants #0836041 and #1226325.
ELECTRICAL DOUBLE LAYER-TYPES-DYNAMICS OF ELECTRON TRANSFER-MARCUS THEORY-TUNNELING - BUTLER VOLMER EQUATIONS-TAFEL EQUATIONS-POLARIZATION AND OVERVOLTAGE-CORROSION AND PASSIVITY-POURBAIX AND EVAN DIAGRAM-POWER STORAGE-FUEL CELLS
Welcome to Posi Tron.
This is our Introductory Presentation regarding the Atomic Structure course. Very soon , we will upload the contents respectively as separate power point presentations.
Please help us to improve by providing your valuable feedback.
Thank You,
Team Posi Tron
The document summarizes an experiment to determine the charge to mass ratio of an electron (e/m) using a Helmholtz coil apparatus. It provides background on the theory and setup of the experiment. Data was collected on the magnetic field and electron beam radius needed to hit targets of different distances. The average calculated e/m ratios were 2.24065 × 1011 c/kg and 2.01474 × 1011 c/kg for magnetic fields lined with and against the Earth's field, respectively. While these differed from the accepted value, the author notes factors like measurement precision that could have contributed to the error.
The document summarizes atomic emission spectra and the origin of spectral lines. It discusses how atoms emit electromagnetic radiation when excited by an energy source. The emitted light is separated into spectral lines using a prism. Gases at low pressure emit discrete spectral lines, forming an atomic emission spectrum unique to each element. The Bohr model explained hydrogen's spectrum by proposing electron orbits of discrete energy levels. Later quantum theory described electron distributions as wave functions and orbitals rather than physical orbits. Spectral lines correspond to electron transitions between energy levels.
This document analyzes the phenomenon of electrostatic attraction between particles from an energy perspective. It proposes that the potential energy between charges is infinite, and justifies this through several analyses. It uses concepts from magnetism, relativity, and Maxwell's equations to show that the magnetic force originating from electron spin is the source of the electrostatic force between charges. This explains the continuous attraction of particles despite vibration and over time. Previous works only considered the energy needed to separate particles, but not the infinite energy holding them together.
The document discusses atomic structure and energy levels in atoms. It begins by focusing on the importance of the hydrogen atom in understanding atomic physics. The hydrogen atom can be solved exactly and its properties extended to other atoms. Its spectra allow for precision tests of theory. Later models like the Rutherford model and Bohr model improved upon the early "plum pudding" model. Bohr's model combined classical mechanics with Planck's idea of quantized energy levels to explain the discrete emission spectra of atoms. His four postulates introduced new ideas like stationary, quantized electron states that allowed atoms to retain energy.
Ion mobility spectrometry (IMS) is an analytical technique used to detect explosives and other chemicals. It works by ionizing vapor samples, separating the ions based on their mobility in an electric field, and detecting the ions. IMS provides fast, sensitive detection and is used in security applications like airports and public events. The document discusses the principles and components of IMS, including ionization methods, ion separation techniques, and factors that determine the resolution, sensitivity and detection limits of IMS systems. Commercial applications of IMS are highlighted, such as explosive detectors, air quality monitors, and portals used to screen people for explosive residues.
Term Paper - Field Assisted Thermionic Emission, Field Emission, and Applicat...Adeagbo Bamise
This document summarizes different types of electron emission from heated metals, including thermionic emission, field emission, and field-assisted thermionic emission (Schottky emission). Thermionic emission occurs when thermal energy from heating overcomes the work function of a metal, allowing electrons to escape. Field emission occurs at room temperature when a strong electric field lowers the potential barrier for electrons. Schottky emission applies an electric field to enhance thermionic emission and lower the barrier at lower temperatures than normal thermionic emission. These emission types find applications in devices like vacuum tubes.
Atomic Structure from A level chemistry.saqibnaveed9
This document provides an overview of atomic structure and the discovery of subatomic particles like electrons. It discusses J.J. Thomson's cathode ray tube experiments in the late 1800s that led to the discovery of electrons and determination of their charge to mass ratio (e/m). It also describes Millikan's oil drop experiment from 1909 that precisely measured the charge of individual electrons as 1.6022×10-19 coulombs and calculated the mass of an electron as 9.1095×10-31 kg.
This document provides information about a High Voltage Engineering course, including:
- The examination scheme which includes marks for internal and end semester exams, as well as term work.
- An overview of the 6 course units which cover topics like breakdown in gases and liquids, generation of high voltages, measurement techniques, and testing of electrical apparatus.
- Detailed content on Unit 1 related to breakdown in gases, including Townsend's theory, ionization processes, and the limitations of Townsend's theory.
The document summarizes various cathode processes and decay processes involved in electrical breakdown in gases. It describes four main ways electrons can be emitted from a cathode surface: 1) photoelectric emission through photon bombardment, 2) electron emission through positive ion or excited atom impact, 3) thermionic emission through heating the cathode, and 4) field emission through very strong electric fields lowering the work function. It also discusses two major decay processes: 1) deionization through recombination of positive and negative ions, and 2) deionization through attachment of free electrons to form stable negative ions, especially in electronegative gases.
This document provides a summary of key concepts regarding electrical breakdown and conduction in gases:
- Gases can act as insulating or conducting media depending on the applied voltage. Low voltages allow small currents, while higher voltages cause electrical breakdown through ionization processes.
- Breakdown occurs through the formation of a conductive spark between electrodes. It involves transitions from non-sustaining to self-sustaining discharges.
- Ionization processes like collisional ionization and photoionization generate free electrons and ions, leading to current growth. Secondary processes like positive ion bombardment and photon emission further sustain the discharge.
- The Townsend theory and streamer theory describe the mechanisms of breakdown under different conditions involving
1. The document describes an experiment to measure the charge-to-mass ratio of electrons using Thomson's cathode ray tube.
2. Two methods are used: 1) null deflection where electric and magnetic fields cancel each other out, and 2) deflection by a magnetic field alone where the radius of curvature is measured.
3. Equations are derived relating the experimental measurements to the charge-to-mass ratio. The results from both methods are within 2% of the accepted value, validating Thomson's original discovery of the electron.
This document discusses Townsend's theory of gas breakdown. It explains that Townsend's theory describes how ionization occurs through collisions between gas molecules and electrons, leading to an avalanche effect. The key points are:
1) Townsend developed equations to model how the number and current of electrons increase exponentially with distance through a gas, depending on factors like the ionization coefficient and secondary ionization processes.
2) His theory can predict the breakdown voltage and distance at which a spark will occur due to a self-sustaining avalanche buildup.
3) The theory applies best at low gas pressures, and needs modifying for electronegative gases that can attach electrons through additional processes.
Townsend ’s theory
Introduction
Ionization by collision
Townsend’s current growth equation
Current Growth in the Presence of Secondary Processes
Townsend’s secondary ionization coefficient
Townsend’s Criterion for Breakdown
Breakdown in Electronegative Gases
This document provides a question bank on the topic of engineering physics for a bachelor's degree program. It includes 70 questions across three sections - short answer, descriptive, and problems. The short answer section contains multiple choice and short response questions testing concepts like band structure of materials, Hall effect, semiconductors, and superconductors. The descriptive section asks students to explain key theories and differentiate between material types. The problems section provides calculations testing conductivity, mobility, drift velocity, and other quantitative applications of the theoretical concepts.
This document discusses the history and development of high voltage engineering. It begins with early experiments with static electricity by ancient Greeks. Key figures who contributed include Franklin, Faraday, Tesla, and Edison. Faraday's law established that a magnetic field can induce current in a wire. Advances allowed longer distance power transmission. Challenges included developing high voltage insulation. Numerical methods like finite element analysis are now used to model electric field distributions in complex high voltage components.
1. This document summarizes an experiment on determining the heat of reaction using a calorimeter. Electrical energy was passed through a coil in the calorimeter, heating the water and increasing its temperature.
2. The experiment aimed to determine the equivalence between electrical/mechanical energy and heat energy. Measurements of voltage, current, water mass, and temperature changes were recorded over multiple trials.
3. The results showed that a larger voltage and current produced a greater increase in temperature over time. This supported the conclusion that a larger amount of electrical energy input leads to a larger amount of heat energy generated.
This document contains an assignment submission that discusses the conductivity of different materials. It begins with an introduction that defines conductors, semiconductors, and insulators based on their conductivity. It then covers energy bands and band diagrams, explaining how they relate to conductivity. Next, it discusses how band diagrams can be used to understand conductivity differences between materials. Finally, it addresses how conductivity in semiconductors varies with temperature, showing that it increases exponentially as temperature rises due to more electrons entering the conduction band. The assignment provides numerical examples and calculations to support the concepts.
(Thompson's Method) Electron's charge to mass ratio. ..(manish & jatin) ...pptJatinMahato1
1. The document describes an experiment to determine the charge-to-mass ratio (e/m) of electrons using Thompson's method.
2. The apparatus used includes an electron gun, e/m tube filled with low-pressure helium gas, and Helmholtz coils to produce a magnetic field. Electrons are accelerated and their path is deflected by the magnetic field.
3. By measuring the diameter of the electron path for different accelerating voltages and magnetic field strengths, the value of e/m is calculated using the equation e/m = 8V/B2d2. The experimentally obtained value of 1.729 × 1011 C/kg agrees well with the accepted value of
This slide set corresponds to the MaterialsConcepts YouTube video "Muddiest Point- Electronic Properties I. Here's the link:
https://www.youtube.com/watch?v=BY8ZPobU8B0
To study the vocab used in this video, visit this site:
http://quizlet.com/24383440/71-electronic-properties-i-conductors-insulators-semiconductors-flash-cards/
This work was supported by NSF Grants #0836041 and #1226325.
ELECTRICAL DOUBLE LAYER-TYPES-DYNAMICS OF ELECTRON TRANSFER-MARCUS THEORY-TUNNELING - BUTLER VOLMER EQUATIONS-TAFEL EQUATIONS-POLARIZATION AND OVERVOLTAGE-CORROSION AND PASSIVITY-POURBAIX AND EVAN DIAGRAM-POWER STORAGE-FUEL CELLS
Welcome to Posi Tron.
This is our Introductory Presentation regarding the Atomic Structure course. Very soon , we will upload the contents respectively as separate power point presentations.
Please help us to improve by providing your valuable feedback.
Thank You,
Team Posi Tron
The document summarizes an experiment to determine the charge to mass ratio of an electron (e/m) using a Helmholtz coil apparatus. It provides background on the theory and setup of the experiment. Data was collected on the magnetic field and electron beam radius needed to hit targets of different distances. The average calculated e/m ratios were 2.24065 × 1011 c/kg and 2.01474 × 1011 c/kg for magnetic fields lined with and against the Earth's field, respectively. While these differed from the accepted value, the author notes factors like measurement precision that could have contributed to the error.
The document summarizes atomic emission spectra and the origin of spectral lines. It discusses how atoms emit electromagnetic radiation when excited by an energy source. The emitted light is separated into spectral lines using a prism. Gases at low pressure emit discrete spectral lines, forming an atomic emission spectrum unique to each element. The Bohr model explained hydrogen's spectrum by proposing electron orbits of discrete energy levels. Later quantum theory described electron distributions as wave functions and orbitals rather than physical orbits. Spectral lines correspond to electron transitions between energy levels.
This document analyzes the phenomenon of electrostatic attraction between particles from an energy perspective. It proposes that the potential energy between charges is infinite, and justifies this through several analyses. It uses concepts from magnetism, relativity, and Maxwell's equations to show that the magnetic force originating from electron spin is the source of the electrostatic force between charges. This explains the continuous attraction of particles despite vibration and over time. Previous works only considered the energy needed to separate particles, but not the infinite energy holding them together.
The document discusses atomic structure and energy levels in atoms. It begins by focusing on the importance of the hydrogen atom in understanding atomic physics. The hydrogen atom can be solved exactly and its properties extended to other atoms. Its spectra allow for precision tests of theory. Later models like the Rutherford model and Bohr model improved upon the early "plum pudding" model. Bohr's model combined classical mechanics with Planck's idea of quantized energy levels to explain the discrete emission spectra of atoms. His four postulates introduced new ideas like stationary, quantized electron states that allowed atoms to retain energy.
Ion mobility spectrometry (IMS) is an analytical technique used to detect explosives and other chemicals. It works by ionizing vapor samples, separating the ions based on their mobility in an electric field, and detecting the ions. IMS provides fast, sensitive detection and is used in security applications like airports and public events. The document discusses the principles and components of IMS, including ionization methods, ion separation techniques, and factors that determine the resolution, sensitivity and detection limits of IMS systems. Commercial applications of IMS are highlighted, such as explosive detectors, air quality monitors, and portals used to screen people for explosive residues.
Term Paper - Field Assisted Thermionic Emission, Field Emission, and Applicat...Adeagbo Bamise
This document summarizes different types of electron emission from heated metals, including thermionic emission, field emission, and field-assisted thermionic emission (Schottky emission). Thermionic emission occurs when thermal energy from heating overcomes the work function of a metal, allowing electrons to escape. Field emission occurs at room temperature when a strong electric field lowers the potential barrier for electrons. Schottky emission applies an electric field to enhance thermionic emission and lower the barrier at lower temperatures than normal thermionic emission. These emission types find applications in devices like vacuum tubes.
Atomic Structure from A level chemistry.saqibnaveed9
This document provides an overview of atomic structure and the discovery of subatomic particles like electrons. It discusses J.J. Thomson's cathode ray tube experiments in the late 1800s that led to the discovery of electrons and determination of their charge to mass ratio (e/m). It also describes Millikan's oil drop experiment from 1909 that precisely measured the charge of individual electrons as 1.6022×10-19 coulombs and calculated the mass of an electron as 9.1095×10-31 kg.
This document discusses the mechanisms of breakdown in gases. It explains that at high electric fields, free electrons in gas can gain enough energy between collisions to cause ionization when striking other molecules. This leads to an electron avalanche effect where the number of electrons increases rapidly. The document outlines various types of ionization processes and theories of breakdown proposed by Townsend, including his first and second ionization coefficients. Townsend's theory of electron avalanches explains the exponential rise in current during breakdown. The document provides mathematical equations to describe current growth based on these coefficients.
The document discusses the principles and physics of welding. It covers topics such as fusion welding processes, characteristics of heat sources like welding arcs, arc structures, and potential drop characteristics. The key points are:
1) In fusion welding, material around the joint is melted to join two parts together. Important factors include the heat source, arc characteristics, filler material deposition, and heat flow.
2) A welding arc is a sustained electrical discharge through an ionized gas that produces heat. It is maintained by thermionic emission and ionization between the electrodes.
3) The voltage drop across a welding arc depends on factors like the electrode material, spacing and current. There is an optimal arc length that produces maximum power
This document summarizes the key electrical properties of metals and semiconductors. It discusses Ohm's law and how electrical conductivity in metals is influenced by drift velocity and current density. It also explains how resistivity is related to temperature in metals. For semiconductors, it describes the band structure of insulators, metals and semiconductors and how conductivity varies with intrinsic carrier concentration and temperature in intrinsic semiconductors. It then discusses the effects of doping on carrier concentrations and conductivity in n-type and p-type extrinsic semiconductors. Finally, it provides an overview of compound semiconductors made of two or three elements.
The document describes the design and construction of a prototype transversely excited atmospheric (TEA) nitrogen laser energized by a high voltage electrical discharge. Key aspects include:
1) The laser uses a Blumlein line discharge circuit to excite nitrogen gas in air using air as the active lasing medium, producing 337.1 nm wavelength laser output of 300 microjoules.
2) The design includes two parallel plate capacitors connected by an inductor to form a Blumlein circuit, charged by a high voltage flyback transformer-based power supply producing 10-20 kV.
3) A spark gap triggers the electrical energy to excite air molecules in the laser discharge channel between two electrodes, producing population
Scattering of Electrons in a Gas (The Franck-Hertz Experiment and the Ionizat...Daniel Bulhosa Solórzano
This document summarizes an experiment to measure the ionization energy of mercury gas and replicate the Franck-Hertz experiment. The experiment used a mercury-filled triode to accelerate electrons into mercury gas. They measured the voltage at which ionization began, finding it to be 9.50 ± 0.85 eV, which agrees with the accepted value of 10.39 eV. They also observed discrete peaks in electron emission from mercury atoms when voltage was varied, supporting Bohr's model that atoms absorb energy in discrete amounts. The average excitation energy was measured to be 4.87 ± 0.36 eV, also consistent with the accepted value of 4.90 eV.
This document summarizes key concepts in high voltage engineering related to insulation breakdown in gaseous dielectrics. It discusses:
1) Different ionization processes that can occur when electrons collide with gas molecules, including simple collision ionization, excitation, double electron impact ionization, and photoionization.
2) Townsend breakdown process where free electrons cause an "electron avalanche" through successive ionizing collisions, leading to exponential growth in the number of electrons.
3) Mathematical analysis of Townsend breakdown using ionization coefficients to describe the number of electrons/ions produced per unit length.
This document summarizes key concepts in high voltage engineering related to insulation breakdown in gaseous dielectrics. It discusses:
1) Various ionization processes that can occur when electrons collide with gas molecules, including simple collision ionization, excitation, double electron impact ionization, and photoionization.
2) Townsend breakdown process where free electrons cause an "electron avalanche" through successive ionizing collisions, leading to exponential growth in the number of electrons.
3) Townsend's first and second ionization coefficients which describe the number of electrons produced per unit length and number of electrons released from the cathode per positive ion, respectively.
Performance analysis of a monopole antenna with fluorescent tubes at 4.9 g hz...Alexander Decker
This document describes the analysis of a monopole antenna design with fluorescent tubes at an operating frequency of 4.9 GHz. The antenna structure consists of 12 commercial fluorescent tubes surrounding a monopole antenna located in the center of a circular ground plane. The performance of the antenna design is analyzed using CST Microwave Studio software. Parameters like return loss, radiation pattern, and gain are evaluated to analyze the antenna's performance. The fluorescent tubes act as plasma reflectors when electrified, trapping radiation inside and improving the antenna's performance for potential military applications.
Thermal size effects in contact metal semiconductor structures are investigated. In thin diodes where the sample size is much smaller than the carrier cooling length, the electron temperature at the contact is much higher than the phonon temperature. Energy is transferred to the environment through electronic thermal conductivity. In thick diodes where the sample size is much larger than the cooling length, the electron and phonon temperatures equalize in the volume. At ohmic contacts in both thin and thick diodes, the temperatures equalize with the environment temperature under ideal heat transfer conditions. The temperatures depend on thermal boundary conditions and sample size, with thermal size effects more pronounced in barrier structures.
lecture classical and Quantum Free electron theory (FERMI GAS) (23-24).pdfLobnaSharaf
The electron theory of solids explains properties through electronic structure. It applies to metals and nonmetals. The theory developed in three stages:
1. Classical free electron theory treated electrons as free gas particles. It could not explain many properties.
2. Quantum free electron theory incorporated quantum mechanics. Electrons occupy discrete energy levels according to Fermi-Dirac statistics.
3. Band theory views electrons moving in periodic potentials of atom arrays. It explains conductivity, effective mass, and the origin of band gaps.
Analysis of Pseudogap in SuperconductorsIOSR Journals
The document analyzes the effect of the pseudogap on the static magnetic susceptibility of the high-temperature superconductor YBa2Cu3O7-δ. Magnetic susceptibility measurements were taken for various levels of oxygen deficiency δ, corresponding to different hole concentrations p. The data shows anomalous suppression of magnetic susceptibility above the critical temperature Tc in the underdoped region, indicative of the presence of a pseudogap. Analysis of the temperature and doping dependence of the magnetic susceptibility provides information about the pseudogap energy scale and its variation with hole concentration p.
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Study Some Parameters of Electrical Discharge in N2 and CO2 Without and With Magnetic Field
1. IOSR Journal of Electronics and Communication Engineering (IOSR-JECE)
e-ISSN: 2278-2834,p- ISSN: 2278-8735.Volume 12, Issue 1, Ver. II (Jan.-Feb. 2017), PP 60-64
www.iosrjournals.org
DOI: 10.9790/2834-1201026064 www.iosrjournals.org 60 | Page
Study Some Parameters of Electrical Discharge in N2 and CO2
Without and With Magnetic Field
Dr. Abdul Hussain A.Khadyair1
,Dr.AhmedHmeed Wanas2
,
Hatem K. Mohaisen3
1(
physics Department, College of Eduction/ University Al-Qadisiyah, Iraq country)
2
(physics Department, College of Eduction/ University Al-Qadisiyah, Iraq country)
3
(physics Department, College of Eduction/ University Al-Qadisiyah, Iraq country)
ABSTRACT:We study the breakdown voltage under low pressure for N2, CO2 gases of with a magnetic field
to the electrode of iron and aluminum with diameter (8.8cm) cm and distance separation between them is
(3cm). by using Passion curve, we measur less effort collapsed, and we notice that less effort is linked to the
collapse of a function held cities and when the magnetic field will be reduced to shed breakdown voltage. Since
the breakdown voltage for CO2 is greater than breakdown voltage N2. Through curved Passion was calculated
(𝛾) and when to shed the magnetic field will increase in value
Keywords: breakdown voltage, secondary emission coefficient
I. INTRODUCTION
Plasma is an ionized gas containing positive and negative ions and electrons and neutral particles and
degrees of ionization changed from 100% (full ionization invader) to low values (10-10
) and this partial
ionization. And referred to the state of the plasma status of Article IV [1]Electrical breakdown in gases is to
transport gas from the insulating state to the conductive state and get the situation by shedding voltage between
the poles parallel submerged in the center of gases will gradually less isolated and at the continuing increase of
the voltage of teams even exceed the critical value called voltage collapse [2] As a result, you will electric
current flows through the center of gaseous discharge to describe the gases and to an electric current flows
through the gas must get ionized molecules to the center [3] And electrons emitted from the cathode are not able
to maintain the electrical discharge without shedding a voltage difference. In the presence of electric potential
difference the electrons near the surface of the cathode will accelerate by the electric field and collide with gas
atoms where the collision between the electrons and the atoms of gas inelastic collision will be established and
this is called a discharge fiery, and operations ionization electrons and ions new and as a result, and as a result of
emitted electrons and secondary generated collisions differ new ionizing and therefore discharge Altohja in
plasma self-sufficient a result of the emission of electrons at the cathode and ionization in the plasma [4].Over
several decades discharge was the subject of great research and a wide area of applications in science and
technology industry, and experiments were conducted with the devices, which have increased considerable
importance for understanding the formation of the system [5]. To study electric discharge characteristics at a
given pressure either by curved voltages and current of the probe or by the spectroscope [6]. the main effect of
the magnetic field on the glow discharge is the cause the electrons and ions to move no longer in straight lines
but its orbit around the magnetic field lines in circular orbits of radius equal to:
re = mv = eB
Where v is the electron velocity, B is the magnetic field and e and m are charge and mass of electron. This
radius is called the larmor or gyro radius. The particle motion across the magnetic field is thus greatly restricted
through the motion along the field is essentially as before. clearly the electron larmor radius is smaller than the
ion radius ( for comparable Te and Ti ) by the factor :
( me / mi ) 1/2
As a result , the electrons are more strongly affected by the magnetic field than the ion[7].
II. ELECTRICAL BREAKDOWN THEORY
by applying an electric field across the gap between the poles, the electrons will deviate with heading
field lines heading towards the anode due to the acquisition of sufficient electron energy, perhaps ionizes the gas
molecules or atoms by collisions with them. In this case we generate a new ions and free electrons originate
new side with the primary. On the electrons after X of the cathode and an ionized electrons will increase (nx),
the equation linking the percentage change in the ionized electrons with the distance from the cathode is
2. Study some parameters of electrical discharge in N2 and CO2 without and with magnetic field
DOI: 10.9790/2834-1201026064 www.iosrjournals.org 61 | Page
dn (x) = αnxdx (1)
Where α represents the first ionization of Townsend (Townsend's coefficient first ionization coefficient) and he
knows the number of ionizing collisions arising from transmission electron rate (1 cm) toward the electric field.
And the nature of the collision of the electron is a statistical process and α term is simply the average value of a
number Altoanat per unit length of the emerging electrons drift for regular the electric field constant. There is no
number of primary electrons emitted from the cathode. It turns out that the number of electrons at a distance (x)
gives by the following relationship:
𝑛 𝑥 = 𝑛° exp 𝛼𝑥 (2)
This equation describe exponentially equation and it seems to be reasonable due to the collapse
produces ionization formidable because of the rate of electron collision process (7). Ions in the gas may be
moving, although the speed is much less than the free electrons because its mass is much greater than the mass
of the electron, it still interacts with the electric field lines.
When you hit the surface of the cathode ions liberated electrons. This ionization process is called process of
secondary ionization cause (secondary ionization). [53] the ionization coefficient actually depends on the
distribution energy the electrons in the gas, which depends only on the (E / P) where (E) hanging electric field,
(P) gas pressure and thus the equation can be written as
𝛼
𝑃
= 𝑓(
𝐸
𝑃
) (3)
This reliability is confirmed in practice. There are a number of secondary processes that contribute to the
electrical breakdown process, some of which include secondary electrons resulting from collisions cation
surface of the cathode, the secondary electrons emitted from the cathode by photons. To calculate these
processes feet Tosind secondary ionization coefficient (γ) can calculate the current through the relationship [8
𝐼 = 𝐼
°
𝑒 𝛼𝑑
1−𝛾 𝑒 𝛼𝑑 −1
(4)
Experimental values for (γ) are determined from the equation (4) and through knowledge of the values of each
of the (p, E, d, α) where (γ) depends on the surface of the cathode properties, and the work function metal and
sessile get high emissions where the value (γ) when they are low values (E / P) and sessile has high when the
values (E / P) high, When the values of (E / P) high, there will be a large number of positive ions and photons
with high energy, including enough to take out electrons from the cathode surface
𝑖 = 𝑖
°
𝑒
𝑝𝑑 𝑓(
𝑉
𝑝𝑑
)
1−𝛾 𝑒
𝑝𝑑 𝑓
𝑉
𝑝𝑑 − 1
(5)
By increasing the voltage, polarizationcurrent at the anode increases according to the equation (4). When
increasing stream Calcined the shrine of the equation (4) becomes zero
𝛾 𝑒 𝛼𝑑
− 1 = 1 (6)
At this point predicted by equation (4-2) to the pole stream becomes indefinitely. This is known as the transition
from self-discharge to electrical breakdown [9]
In 1889 the deployment of the world's Passion (Friedrich paschen) law known as the Passion law.
Since the breakdown voltage (VB) between the electrodes is a function of (pd) and the resulting pressure inside
the pipe and the distance between the electrode where he found the following relationship
𝑉
𝐵
=
𝐵𝑃𝑑
ln
𝐴𝑝𝑑
ln
1
𝛾
(6)
III. PREPARATION EXPERIENCE
To study the electrical discharge in the gaseous bi-dioxide and nitrogen We used a tube of glass Albaerks length
(30cm) and outer diameter (10cm). The innerdiameter (9.4cm)are containing three holes in order insert the
probe to study the properties
3. Study some parameters of electrical discharge in N2 and CO2 without and with magnetic field
DOI: 10.9790/2834-1201026064 www.iosrjournals.org 62 | Page
Figure 1 represents discharge unloading system dc
Figure ( 1) illustrates the scheme for electric circuitused to measure the voltage collapse of gases
We used poles flat surface discs for different materials Authority (aluminum, iron ) with a diameter
(8cm.8) and thickness (1cm) respectively and (3cm) the distance between the electrode and using the pump
unloading to unload tube Albaerks to pressure (0.01mbar) which is the minimum can be up to this pump the
suitable for work pressure and to measure the pressure within the system we use a Pirani type (EDWARDS) and
serial number to him (D395-90-000) and the gas pressure within the system changes from (0.053 - 2.28 torr). To
generate a magnetic field we consider a file on the glass tube consists of (950) rolls to generate a magnetic field
up to 120 G
IV. RESULTS AND DISCUSSION
For measuring the collapse of the gases effort, and breakdown voltages in the gas depends on the gas pressure
and the distance between the polarization which consider to measure the collapse of Ghazi dual dioxide efforts
(co2) and nitrogen (N2), where pd range of gas bi-dioxide is a bout (0.18 - 1.5 Torr.cm) for nitrogen (0.4 - 2.28
Torr.cm)
4. Study some parameters of electrical discharge in N2 and CO2 without and with magnetic field
DOI: 10.9790/2834-1201026064 www.iosrjournals.org 63 | Page
Measuring the breakdown Voltage of the Gaseous bi-dioxide and Nitrogen
In Figure ( 2 ) shows a curved Passion for dual-dioxide gas by using four electrodes. Where we noticed
less effort the collapse is of the two poles occurs when the value of pd is equal to (0.456 Torr.cm). the less effort
collapse of the gas depends on type cathode electrode material and that means different work function metal
cathode electrode material affect on the lower voltage collapse. Left end of the curve Passion decreases when
increasing the value of (pd) due to the increased the number of collisions between electrons and neutral atoms.
the right of curved Passion denote voltage collapse Teda which increase with increase in the value of (pd) due to
fact of the low ionization section so the electrons need more energy to occur collapse so increasing voltages[10].
Figure ( 3 ) illustrates the Passion curve of nitrogen gas using four poles. Less electrical breakdown of the four
poles occurs at value of(pd = 0.9 Torr.cm). we noticed that the effort collapse of nitrogen gas is less than the
collapse of a bilateral effort carbon dioxide gas. When we shine a magnetic field on the edge of the cathode This
makes the path of electrons moving spiral standing, the plasma frequency increases depending on the number of
collisions as a result of inventory decreases plasma collapse of gases effort
(Vb)min (volt)
B=120G , N2
(Vb)min (volt)
B=0G , N2
(Vb)min (volt)
B=120G , CO2
(Vb)min (volt)
B=0G , CO2
∅ (𝑒𝑉)Cathode material
1762023603923.6Aluminium (Al)
2092324154374.63Iron ( Fe)
Table (1) The work function ∅ and the minimum breakdown potential for different type and different gases .
((Figure 3) as a function of voltage collapse pd andthe influence of the magnetic field of gas co2
Secondary Emission Coefficient
The variation of the secondary electron emission coefficient 𝛾 the reduced field E/P as show in fig.
4 and 5 for co2 and N2, respectively. It usually observed that the curve of 𝛾(𝐸/𝑃) has minimum[11] . but in the
experimental range of reduced field, we investigated only the ascending branches of the curves are obtained . we
show that ˠ rises faster for CO2 then for N2 and that it increases with the magnetic field, while especially for
argon , becomes less effective as the reduced field is decreesed . the secondary emission of electrons can be due
to any combination of effects of impacts of positive ions , photons , excited atoms on the aluminum electrode
and depends also on the state of the cathode surface . for weak reduced fields , the mean electron energy is low
and excitation within the gas becomes more important than ionization . secondary electrons are then ejected
350
400
450
500
550
600
0 0.5 1 1.5 2
﴿volt﴾Vb
﴿cm.torr﴾pd
Al , without Mag. F.
Al , with Mag. F.
Fe , without Mag. F.
Fe , with Mag. F.
5. Study some parameters of electrical discharge in N2 and CO2 without and with magnetic field
DOI: 10.9790/2834-1201026064 www.iosrjournals.org 64 | Page
from the cathode mainly by pho-ton impact ( photoelectric effect ) , a mechanism less sensitive to the magnetic
field . on the other hand , at high values of Eon the other hand , at high values of EP the secondary electron
emission is governed by impact of ions on the cathode and , at even higher values , by the impact of neutral
rapid species . these mechanisms are dependent on the dynamics of the charged particles , and the emission of
secondary electrons is enhanced by the confinement effect promoted by the application of a magnetic field . the
magnetic field effect associated with the increase of , at a given value of EP, is equivalent to a decrease in the
work function of the cathode material , because , in the presence of a B-field , a lower voltage would be required
to maintain the discharge as would be for case of field-free discharge but with a cathode of lower work function
. the efficiency of electron emission by the incidence of the ions onto the cathode increases when using a smaller
ion mass
CONCLUSIONS
The breakdown voltage in low pressure gases have been measured for argon and nitrogen discharge
using plane-parellel aluminum electrodes. We have investigated the influence of a longitudinal magnetic field
on the Paschen curves and on the Townsend parameters . we observed that the magnetic field applied along the
discharge axis promoted a reduction of the breakdown voltage . the breakdown is facilitated by the magnetic
confinement of electrons which reduces the electron losses and effectively increases the collision frequency
between electrons and the gas particles at a given reduced field , thus increasing the ionization efficiency . this
effect is equivalent to a change of the operating gas by another of low ionization potential . the presence of the
magnetic field enhances the secondary ionization coefficient at a given E/P value .
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