Thursday 28 July 2011
Hayley Smith with some of the ISIS stripping foils
View full-size image
Hayley Smith, from the Synchrotron Physics group, was awarded second place at this years "Present Around the World" competition, for her outstanding presentation on foil studies
Present Around the World (PATW) competitions are technical presentation competitions in which students and young professionals give a ten minute presentation on an engineering or technology subject of their choice.
Having won the Local and Regional heats Hayley Smith from the ISIS Synchrotron Physics group presented her stripping foil studies at the National final in Birmingham on 23 July 2011. Hayley's awe-inspiring combination of great presentation skills and interesting content proved successful, winning her second place and £300. Over the three heats, she won a grand total of £650 and a year’s free membership to the IET. As Hayley says, "it's not bad for half an hour’s work!"
PATW is one of the most prestigious technical competitions organized by IET (Institute of Engineering and Technology). The competition provides students with a platform to present their ideas on technology and innovation as well as non technical topics in front some eminent judges. The competition is arranged in four levels: Local, Regional, National and Global finals in UK. The judging is split 25% technical content, 75% presentation skills, enabling students (aged 18 or above) and young professionals (graduated within the last seven years) at varying levels of their studies or career to participate.
About Hayley’s research
Beam from the ISIS linear accelerator is stripped of electrons before entry into the ISIS synchrotron ring. a thin (0.3µm) Aluminium Oxide stripping foil converts H- ions into protons (H+), by, H-
Potential ISIS upgrade scenarios replacing the existing 70 MeV linear accelerator with one of 180 MeV have been studied. Such an increase in beam energy and intensity is incompatible with the present foil system. Various foil parameters have been investigated, with the aim of developing a foil specification suitable for 180 MeV injection into ISIS. Some of the main figures of merit, considered in the study were:
• Stripping efficiency (i.e. how good the foil is at removing the electrons) - this depends on the foil material, foil thickness and incident beam energy. Thicker foils have better stripping efficiency.
• Scattering - As the incident beam passes through the foil it undergoes collisions with foil material atoms. These can cause the beam to exit the foil at a dispersive angle, with the potential for this beam to be uncontrolled and lost, putting a limit on operational intensity. The effect of scattering is greatest in thicker foils.
• Temperature - Bombarding a thin foil with high energy particles causes the temperature of the foil to rise. Problems can arise if hot-spots are created, or if the foil temperature becomes excessive as slight evaporation of the surface may occur. This reduces the foil thickness which in turn decreases the stripping efficiency and ultimately leads to shorter foil lifetimes.
Modelling of the foil interactions was benchmarked against current ISIS operations and experimental results and simulations from J-PARC, the SNS at ORNL and Linac4 at CERN. An proposed electron-stripping foil for 180 MeV injection into the ISIS proton synchrotron would be made from amorphous carbon with a foil thickness of 200µg/cm2
|Other STFC||News||Site Sections||Important Links|