The aim of the front end test stand project is to demonstrate that chopped low energy H(-) beams of high quality can be produced. The beam line currently consists of the ion source, a 3 solenoid low energy beam transport and a suite of diagnostics. A brief status report of the radio frequency quadrupole is given. This paper details the work to optimize the ion source performance. A new high power pulsed discharge power supply with greater reliability has been developed to allow long term, stable operation at 50 Hz with a 60 A, 2.2 ms discharge pulse and up to 100 A at 1.2 ms. The existing extraction power supply has been modified to operate up to 22 kV. Results from optical spectroscopy measurements and their application to source optimization are summarized. Source emittances and beam currents of 60 mA are reported.

In order to reduce the emittance and increase the transported beam current from the ISIS Penning-type H(-) ion source, improvements to the extraction system are required. This ion source is currently being commissioned on the front end test stand at the Rutherford Appleton Laboratory, which demands higher extraction energies, higher beam currents, and smaller emittances. To facilitate this, the present geometry requires optimization. This paper details the experimental and simulation studies performed of the plasma meniscus and the possible electrode geometry modifications needed to extract the highest quality beam.

The aim of the front end test stand (FETS) project is to demonstrate that chopped low energy beams of high quality can be produced. FETS consists of a 60 mA Penning Surface Plasma Ion Source, a three solenoid low energy beam transport, a 3 MeV radio frequency quadrupole, a chopper, and a comprehensive suite of diagnostics. This paper details the design and initial performance of the ion source and the laser profile measurement system. Beam current, profile, and emittance measurements are shown for different operating conditions.

A noninvasive, compact laserwire system has been developed to measure the transverse emittance of an H − beam and has been demonstrated at the new LINAC4 injector for the LHC at CERN. Light from a low power, pulsed laser source is conveyed via fiber to collide with the H − beam, a fraction of which is neutralized and then intercepted by a downstream diamond detector. Scanning the focused laser across the H − beam and measuring the distribution of the photo-neutralized particles enables the transverse emittance to be reconstructed. The vertical phase-space distribution of a 3 MeV beam during LINAC4 commissioning has been measured by the laserwire and verified with a conventional slit and grid method.

The ISIS H(-) Penning surface plasma source has been developed to produce beam currents up to 70 mA and pulse lengths up to 1.5 ms at 50 Hz. This paper details the investigation into beam extraction and beam transport in an attempt to understand the beam emittance and to try to improve the emittance. A scintillator profile measurement technique has been developed to assess the performance of different plasma electrode apertures, extraction electrode geometries, and postextraction acceleration configurations. This work shows that the present extraction, beam transport, and postacceleration system are suboptimal and further work is required to improve it.