GBS - March 8, 2019

Questions to Answer and Plots to Make

Ion/Secondary Production

• Is production rate proportional to (current, pressure)? does it scale with ionization cross-section beam energy?
• Is trap density proportional to production rate, i.e. scale w/ (current, pressure, time)? similarly, for beam energy?

Magnetic Trap Threshold

• Does trap density depend upon the magnetized solenoid current? if yes, what is the dependence on current?
• Does the min magnetizing current to sustain a trap, depend on the max magnetizing current?
• or is it a fixed threshold, independent of beam energy, current, pressure, time, etc?

Role of Anode Bias

• Is the anode bias essential for magnetic trapping of ions?
• ... or rather, what impact does the anode bias have on the trap efficiency or trap density?

Role of the Electron Beam

• Must the primary electron beam be run? if FE is present, is this sufficient? in lack of photo- or FE- beam, is there any notable ion production?
• Can trap density co-exist w/ electron beam? is there a beam clearing effect, i.e. can trap density remain only when beam is "OFF"
• ...if yes, then what is this limit, pA, nA, is FE enough, or if NO is there a dependence on beam current?

Diagnostics and Measurements Plan at the GTS

media:190308_GTS_Plan.pdf