Ion Source Hydrogen Positive (ISHP) is a microwave based ECR proton source installed at ESS Bilbao. This source is the first element of the injector that will be employed in future application of high proton current in the
field of research projects and for industrial processes. ISHP produces over 30 mA of pulsed proton beam by operating at 2.7 GHz. The magnetic field is produced by two independently movable coil pair and the extraction system is composed of a plasma electrode at high voltage platform potential, two ground electrodes and a negatively biased screening electrode inserted between the ground electrodes. The last three electrodes are contained in the extraction column, and can be moved as a group by stepper motors, to change the distance between the plasma electrode and first ground electrode. Measurements with different extraction system
setups have been performed.
The injector is expected to produce a proton beam with an energy of 45 keV and high intensity with a rms emittance around 0.25 π mm mrad in order to fulfil the requirements of the RFQ. One innovative feature of ISHP is the possibility to vary the gap between the plasma chamber and the extraction electrodes; the so called acceleration gap.