Custom atomic beam source

Team Members

Lu Tiangao, Li Putian

Introduction

In this report, we introduced an atomic oven designed by ourselves. The whole design will be suitable for atoms that need temperature ranging from 500K to 1300K. The idea came from our lab's commercial atomic beam source was both expensive and having some defects.

Theory part

Vapor Pressure

Indium is the group III atom, and it has two stable isotopes In-113 and In-115, the atom we use is In-115 with an abundance of 95.7%, the melting point is 156.6°C\\ To calculate the density of atoms coming from the nozzles. We should know the pressure and temperature of the gas, which the density formula is given by: \begin{equation} \rho(T)=\frac{p(T)}{k_{B}T} \label{eqn:density formula} \end{equation} When a material is in thermodynamic equilibrium with its vapor at a given temperature in a closed system, the pressure at this time is called vapor pressure.\cite{wiki:vp_pre}\\ The vapor pressure of indium is given by \begin{equation} \lg\frac{p}{Torr}=8.003-\frac{12180}{T+273.15} \end{equation} cited from \cite{vaporpressure}\\ We can plot the vapor pressure with Temperature range from 800$^{\circ}$C to 1000$^{\circ}$C

${\begin{alignedat}{2}\psi &=Ae^{i(kx_{1}-\omega t}+Ae^{i(kx_{2}-\omega t)}\\&=Ae^{-i\omega t}e^{ik{\frac {(x_{1}+x_{2})}{2}}}[e^{ik{\frac {(x_{1}-x_{2})}{2}}}e^{-ik{\frac {(x_{1}-x_{2})}{2}}}]\\&=2Acos[k({\frac {x_{1}-x_{2}}{2}})]e^{i[k{\frac {(x_{1}+x_{2})}{2}}-\omega t]}\end{alignedat}}$

Custom oven design

Items needed

• Custom Flange feedthrough
• Thermocouples and thermocouple feedthrough
• Tantalum heating wires and current feedthrough
• Crucible and nozzle
• PBN holding rings
• Vacuum Flange, cube and viewports
• Heating wire power system
• Cooling system for oven

Oven setup

• Wiring practice

• Washing parts for vacuum