C-Band LINAC for a race track microtron
252
pages
English
Documents
2010
Le téléchargement nécessite un accès à la bibliothèque YouScribe Tout savoir sur nos offres
252
pages
English
Ebook
2010
Le téléchargement nécessite un accès à la bibliothèque YouScribe Tout savoir sur nos offres
Publié par
Publié le
01 janvier 2010
Nombre de lectures
35
Langue
English
Poids de l'ouvrage
12 Mo
Publié par
Publié le
01 janvier 2010
Nombre de lectures
35
Langue
English
Poids de l'ouvrage
12 Mo
UNIVERSIDAD COMPLUTENSE DE MADRID
FACULTAD DE CIENCIAS FÍSICAS
Departamento de Física Atómica, Molecular y Nuclear
C-BAND LINAC FOR A RACE TRACK
MICROTRON.
MEMORIA PARA OPTAR AL GRADO DE DOCTOR
PRESENTADA POR
David Carrillo Barrera
Bajo la dirección del doctor
Vasily Ivanovicht Shvedunov
Madrid, 2010
ISBN: 978-84-693-8239-4 © David Carrillo Barrera, 2010
CIEMAT
Unidad de Aceleradores
UNIVERSIDAD COMPLUTENSE DE MADRID
Departamento de Física Atómica, Molecular y Nuclear
TESIS DOCTORAL
LINAC EN BANDA C PARA UN MICROTRON
DE PISTA
C-BAND LINAC FOR A RACE TRACK
MICROTRON MICROTRON
Memoria realizada por
David Carrillo Barrera
para optar al grado de Doctor
Director de Tesis: Dr. Vasiliy Ivanovich Shvedunov
Madrid - 2010 CONTENTS CONTENTS
1 Introduction .............................................................................................................................. - 1 -
1.1 State of the art ........................ - 2 -
1.2 Objectives and thesis structure ............................................................................................... - 5 -
1.3 Introduction to Particle Accelerators ...................... - 7 -
1.3.1 The purpose of particle accelerators ........................................................................... - 7 -
1.3.2 History of accelerators ............................................................... - 10 -
1.3.3 Typical components in a particle accelerator ............................................................ - 20 -
1.3.3.1 Particle sources ........................................................................ - 20 -
1.3.3.2 RF cavities ................................................ - 20 -
1.3.3.3 Beam guiding and focusing devices ......... - 21 -
1.3.3.4 Injection and extraction devices .............................................. - 22 -
1.3.3.5 Diagnostics ............................................................................... - 23 -
1.4 Circular and race-track microtrons ....................................................... - 24 -
1.4.1 Circular Microtron ...................................................................................................... - 24 -
1.4.2 Race-Track Microtron (RTM)...................................................... - 26 -
1.4.2.1 Brief history of RTM ................................. - 26 -
1.4.2.2 Principles of operation ............................................................................................. - 26 -
1.4.2.3 Summary of RTM characteristics ............................................................................. - 29 -
1.4.3 RTM applications ...................................................................... - 30 -
1.4.3.1 Low energy nuclear physics ..................................................................................... - 31 -
1.4.3.2 Injectors ................................................... - 31 -
1.4.3.3 Radiotherapy ........................................................................... - 32 -
1.4.3.4 Elemental analysis ................................... - 32 -
1.4.3.5 Medical Isotopes Production ................................................................................... - 33 -
1.4.3.6 Cargo inspection ...... - 34 -
1.5 RTM parameters dependence on operating wavelength ...................................................... - 36 -
1.6 12 MeV RTM specification .................................................................................................... - 39 -
2 Accelerating Structures: Theoretical Background .... - 43 -
2.1 Basic microwave concepts .................................................................................................... - 43 -
2.1.1 Introduction ............................................................................... - 43 -
2.1.2 Waveguides and transmission lines ........... - 45 -
i
2.1.3 RF Cavities in accelerators ......................................................................................... - 47 -
2.2 Travelling and standing wave accelerating structures for electron linacs ............................ - 50 -
2.2.1 Travelling wave structures ......................................................................................... - 50 -
2.2.2 Standing wave structures .......................... - 52 -
2.3 Types of normal and superconducting standing wave accelerating structures .................... - 53 -
2.3.1 Normal Conducting Cavities ....................................................................................... - 53 -
2.3.2 Superconducting cavities ........................... - 53 -
2.4 Main parameters of the standing wave accelerating structure ............................................ - 55 -
2.4.1 Quality factor and external coupling with RF cavities ............... - 55 -
2.4.2 Electric field, energy gain, transit time factor, shunt impedance and synchronous
particle - 58 -
2.4.3 Coupling between cavities ......................................................................................... - 60 -
2.4.4 Pulsed and continuous mode: Duty factor ................................ - 60 -
2.5 Dependence of the standing wave accelerating structure parameters on wavelength........ - 61 -
2.6 Standing wave accelerating structure description in lumped circuit theory ......................... - 65 -
2.7 Modes of accelerating structure. Dispersion characteristic .................................................. - 68 -
2.8 Numerical methods and codes for accelerating structure optimization ............................... - 72 -
2.8.1 RTM Trace .................................................................................................................. - 72 -
2.8.2 Superfish .................... - 72 -
2.8.3 Ansys .......................................................................................................................... - 73 -
2.8.4 Ansoft HFSS ................................................ - 73 -
2.8.5 CST Studio ................. - 74 -
2.9 Main steps of standing wave accelerating structure optimization ....................................... - 75 -
3 C-band RTM linac optimization ................................................................ - 77 -
3.1 Peculiarities of RTM linac ...................................... - 77 -
3.2 RTM linac parameters specification ...................................................................................... - 79 -
3.3 Electrodynamics characteristics optimization ....................................................................... - 81 -
3.3.1 2D linac optimization with RF and beam dynamics codes ......................................... - 82 -
2.5.2.1 Regular =1 cell optimization ................................................................................. - 82 -
3.3.1.1 End =1 cell calculations .......................... - 86 -
3.3.1.2 First <1 cell calculation and linac optimization ...................... - 87 -
3.3.1.3 Summary of 2D linac optimization ........................................................................... - 91 -
3.3.2 3D linac cells calculation, coupling factor and field distribution optimization .......... - 92 -
3.3.2.1 Initial considerations ................................................................................................ - 92 -
ii
3.3.2.2 Order of 3D calculations: Methodology ................................................................... - 94 -
3.3.2.3 Step (a). Calculation of regular cell (2a=2b=3a=3b=4a) without coupling slots. ..... - 95 -
3.3.2.4 Step (b). Calculation of short end cell (1a+1b) without coupling slots. ................... - 97 -
3.3.2.5 Step (c). Tuning 2b+3a assembly with coupling slots .............................................. - 98 -
3.3.2.6 Steps (d), (e). Tuning 2a+1b+1a assembly with coupling slots. ............................ - 102 -
3.3.2.7 Step (f). Tuning 4b+4a+3b assembly with coupling slots ....... - 105 -
3.3.2.8 Step (g). Calculation of the full assembly: 1a+1b+2a+2b+3a+3b +4a+4b .............. - 107 -
3.3.2.9 Step (h) Optimization of accelerating structure coupling with waveguide ........... - 111 -
3.3.2.10 Summary of 3D linac optimization ......................................................................... - 118 -
3.3.3 Calculations of the tolerances for basic cell dimensions ......... - 119 -
3.3.4 Analysis of multipole fields caused by the coupling slots and waveguide ............... - 125 -
3.3.4.1 Effect of couplin
