2023-03-21

Machine Status

Vacuum is 2.4e-7 Pa (yesterday was 2.3e-7 Pa).

TORA signal is greater than ±100 mV at injection.

FAB signal is larger.

Equipment

The Channel-1 scope termination has been changed to 50 Ω. Noise has been noticeably reduced, so we will use 20 mV/div rather than 50 mV/div. 

Measurements and Today's Plots

Today's plan is to vary the gap between beam-1 and beam-2 by adjusting the voltage when phi_s=0.  We repeat this for different values of the energy gap (see description from yesterday). Yesterday we had a minimum dP/P for the 6.98 ms script (165 keV gap), so we will use that as a central point and vary around it.

We will make scripts for 6.985 (148 keV) and 6.975 ms (183 keV). We will also do this with (0.9 * 1.18 kV), (1.0 * 1.18 kV), (1.1 * 1.18 kV) for each gap setting. We need to speed up the acquisitions to take 9 sets of data; which is already more data than yesterday. To achieve this, we will skip the later acquisitions at 200 and 273 ms. We will only take acquisitions at 25 ms, 122 ms and 360 ms. This gives us the two bunched regions and one coasting region.

We will still acquire 5 beam-on and 2 beam-off datasets.

Measurement 1 - Case 1

This is a repeat of the first measurement yesterday. It will just confirm we've got a clear Schottky peak and verify that noise is reduced with the change in scope settings.

Noise has reduced in amplitude by around 50%. Signal amplitude seems to have reduced by around 30% (40 -> 28)

Measurement 2 - 1.0 * 1.18 kV - 6.980 ms (165 keV gap)

Data for 273 ms delay taken later.

Measurement 3 - 1.0 * 1.18 kV - 6.975 ms (184 keV gap)

Measurement 4 - 1.0 * 1.18 kV - 6.985 ms (148 keV gap)

Data for 273 ms delay taken later.

Measurement 5 - 1.0 * 1.18 kV - 6.990 ms (130 keV gap)

From here, Shinji will make the AWG scripts, so we have more available time and we will start to acquire with a 273 ms delay again. From now on there will be four delay settings, 25ms, 122ms, 273ms and 360 ms.

Measurement 6 - 1.298 kV - 6.960 ms (165 keV gap)

It was noticed that if the voltage is changed then the final energy will be different if we use the same acceleration time. To correct for this we need to adjust the acceleration time. 

Measurement 7 - 1.298 kV - 6.965 ms (147 keV gap)

In the middle of this measurement the ion source was changed, and the signal was doubled. The plots below have been provided, but a repeat of Case 1 will be performed and then this measurement will be repeated.

Measurement 8 - Case 1

The ion source arc settings were changed which resulted in the TORA signal nearly doubling. We repeated a case-1 measurement to check the single-beam dP/P.

Measurement 9 - 1.298 kV - 6.970 ms (130 keV gap)

Measurement 10 - 1.298 kV - 6.965 ms (147 keV gap) - REPEAT

This was a repeat of measurement 7 because of the change in intensity.