Test of the primary ion beam signals with the array detector. The noise level is about -50uA even with bias.
1. Address Trek readback noise: there is a 20-30kHz sinusoidal noise superinposed on the readback of the primary 4kV treks. Find use 50-300Ohm resister as a terminator can reduce this noise. But some time cause saturation at readback. Need more study at this problem.
2. Try self-bias scheme to measure the maximum ion current on the shutter.
Four turns filament ion source #1, accelerator columns shorted to the GND from #3 numbered from the top
I_shutter = 9.8uA, V_shutter = 64V, Wb = 33keV (The DMM is across the 6.3MOhm resister & uA meter)
I_shutter = 7uA, V_shutter = 44V, Wb = 44keV
Continue the shutter self-bias test: (The DMM is across the 6.3MOhm resister)
I_shutter = 14uA, V_shutter = 57V, Wb = 45keV
I_shutter = 21uA, V_shutter = 84V, Wb = 60keV
1. Re-install the secondary beamline. 2. MST meeting. 3. Uday gave a talk at the group meeting
4. Roughing down the secondary beamline and the analyzer.
1. Move the control rack and the secondary power rack to the working position
2. Primary sweep plates conditioning (Diane)
3. Continue the shutter self-bias test
I_shutter = 28uA, V_shutter = 107V, Wb = 60keV
I_shutter = 68uA, V_shutter = 261V, Wb = 70keV
1. Secondary sweep plates conditioning (Diane)
2. Study the focus of the beam at 44.5keV. (I_shutter = 14-20uA, V_shutter = 52-80V, size at BPM ~ 8mm)
1. Study the focus of the beam with the grey wire on the shutter
Wb = 45keV, I ~ 5uA, If ~ 4.5A, size at BPM ~ 6mm, size at wire ~ 5mm
Wb = 45keV, I ~ ?, If ~ 5A, size at wire ~ 10mm
Wb = 45keV, I ~ 10uA, If ~ 6.2A, size at wire ~ 15mm
2. Run secondaries into the analyzer
Wb = 45keV, noise ~ 15nA, no signal was detected.
1. Change ion source. #2 of the four turns. Start emitting If ~ 5A, Ib is small
2. Change ion source. #3 of the four turns. Start emitting at If ~ 3.5A.
3. Wb = 40keV, I_shutter ~ 30uA w/o bias.
4. Radial sweep the beam, hits # 2,3,4,5,6,7,8 pins.
5. Run plasma and analyzer. No signals were detected.
Alighment of the primary beamline with the sweep plates
1. Continue to align the primary beamline
2. Change the ion source to #4, four turns. (#3 just yields ~3uA at 8A filament current)
3. Adjust the parallel of the Pierce and the Extractor
Continue to align the primary beamline