Conductance Control Iris for the K150 Cyclotron H- ion Source BY ARMANDO MALDONADO ADVISORS: DR. HENRY CLARK, DR. GABRIEL TABACARU

Introduction Negative Hydrogen Ion source Hardware Set-up Operation General operation, problem Improvement, basis for my project Hardware Set-up Operation Programming an Interface Possible problems Future Plans Acknowledgements

Negative Hydrogen Ion Source H- Source for intense proton beams for Upgrade Project Large hydrogen gas flow needed for H- operation H2 travels past turbo pumps Poor vacuum limits intensity ~10-8 torr – source off, ~10-6 torr – source on Install conductance Iris below turbo pumps Failsafe and reproducible H- ion source turbo molecular pumps (remove hydrogen) to K150 Cyclotron Cryogenic pumps (don’t remove hydrogen well)

Project Aim

Hardware 8” OD Conflat DV Manufacturing Inc. iris ~4.7” diameter when fully open ~0.3” diameter when fully closed

Hardware Cont. optical encoder present non-volatile memory MDrive 17 Plus control motor Modern step-by-step motor optical encoder present accurate determination of the movement non-volatile memory store variables rich programming capabilities

Set-up Coupling apparatus Power Supply Data Fitting

Set-up: Coupling apparatus

Set-up: Assembled Product Connecting shaft Set screw couplers for dampening Aluminum Spring Loaded

Set-up: Power Supply Power Supply Storage 120 VAC, 24 VDC output Unregulated power source Low Noise Storage Stored away from ion source Indicator light Grounded to box

Fitting Data Conversion factor needed Linear or something else? Iris Diameter as a function of Motor steps Measured with venire caliper at increments of 200 motor step intervals Plotted data and fitted regressions Linear fit Cubic fit Cubic function fits data better

Plotted Data

Flow Chart

Programming an Interface Control Iris Diameter input Increment/Decrement Resolution Reading diameter True diameter of iris Error Status Input bounds/motor state Initialize Set-up Read Position without moving Reset Motor and Diameter

Block Diagram

Future Projects Gas Baffle for the Light Ion Guide for the Upgrade Project Conductance control Similar application as with H- ion source Beam intensity attenuator for any ECR (Electron Cyclotron Resonance) ion source Rapid reduction of beam intensity into the cyclotron Compact and will replace attenuator screen system

References – H- ion source [1] H. L. Clark, F. Abegglen, G. Chubarian, G. Derrig, G. Kim, D. May, G. Souliotis and G. Tabacaru, Progress in Research, Cyclotron Institute, Texas A&M University (2009-2010), p.V-12 – V-17 [2] H. L. Clark, F. Abegglen, G. Chubarian, G. Derrig, G. Kim, D. May, G. Souliotis and G. Tabacaru, Progress in Research, Cyclotron Institute, Texas A&M University (2010-2011), p.V-2

Thank you! Andy Clark Steve Russel Robert Burch Control Systems Machine Shop Steve Russel Electronic Shop Robert Burch Control Systems