Abstract
A low temperature oven has been developed to produce calcium beam with Electron Cyclotron Resonance Ion Source (ECRIS). The atom flux from the oven has been studied experimentally as a function of the temperature and the angle of emission by means of a quartz microbalance. The absolute flux measurement permitted to derive Antoine's coefficient for the calcium sample used: A=8.98± 0.07 and B=7787± 110 in standard unit. The angular FWHM of the atom flux distribution is found to be 53.7±7.3∘ at 848 K, temperature at which the gas behaviour is non collisional. The atom flux hysteresis observed experimentally in several laboratories is explained as follows: at first calcium heating, the evaporation comes from the sample only, resulting in a small evaporation rate. Once a full calcium layer has formed on the crucible refractory wall, the calcium evaporation surface includes the crucible's enhancing dramatically the evaporation rate for a given temperature. A Monte-Carlo code, developed to reproduce and investigate the oven behaviour as a function of temperature is presented. A discussion on the gas regime in the oven is proposed as a function of its temperature. A fair agreement between experiment and simulation is found.
Highlights
This work is dedicated to the study of a low temperature metallic oven dedicated to calcium beam production at the SPIRAL2 facility at GANIL, France [1, 2]
This study is the first step of longer term plan to build an end-to-end simulation able to optimize and predict the atom to ion conversion yield of oven to produce beams in Electron Cyclotron Resonance Ion Source (ECRIS)
The atom flux is measured with a quartz AUDA6 Neyco micro balance
Summary
This work is dedicated to the study of a low temperature metallic oven dedicated to calcium beam production at the SPIRAL2 facility at GANIL, France [1, 2]. The differential atom flux from the oven is measured and compared. The experimental setup used to study the differential atom flux from the oven is described. Setup The oven metallic atom emission has been measured in a dedicated vacuum chamber (see Fig. 2) with a residual pressure P0 = 10−7 mbar. The atom flux is measured with a quartz AUDA6 Neyco micro balance. The quartz is inserted into a mechanical support resulting in an active measurement disc diameter of 8.1 mm. When evaporated metallic atoms are deposited on the quartz surface, its mass increases and changes its mechanical resonance frequency. The quartz frequency measurement is done with a dedicated Inficon controller which displays the instantaneous frequency and calculates the mass per cm accumulated during a programmable integration time.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
