Date: 06/04/2018 (after 16:40)
We powered the preamps for the two S2 detectors and the diode.
We biased the detectors:
- Downstream S2 bias = -130.1V, leak I = 2.18uA
- Central S2 bias = -129.9V, leak I =16.71 uA
- diode bias = -70.1V, leak I = 0.01uA
The target ladder was set to position II (No target/frame).The downstream iris was closed to 18mm diameter (actuator setting = 82.5mm). The central iris was closed to 18mm diameter (actuator setting = 85.5mm)
We were ready to begin beam tuning with 7Li.
With no beam, DAQ DT = 2%, trigger rate ~ 800Hz, event mult = 3.6. The DAQ OR is from the central S2 and diode.
During the tuning we had a problem with the CSSM valve -> this is needed to operate the CSSM ERNA magnet for bending the beam into the electron suppressed Faraday cup FC-E1, located downstream from the chamber.
Raffaele fixed this by using an older version of the CSSM magnet labview software.
During tuning we cut the beam using the High Energy slits, the final slit positions were 1mm for the Up, Down, Right, and Left
After tuning with no target frame in the beam axis, we had: FC-4 = 138 pA and FC-E1 = 120 pA, Total transmission = 87%
We set the target ladder to position IV, target CH2 III. The central iris was opened (central actuator = 14.0mm).
At 17:50 we started the DAQ for 5.0MeV 7Li 2+ on target CH2 III. The beam current on FC-0 (immediately before chamber) was 118 pA.
- DT = 18%
- Save name: 180406165546
We saw no signal on the diode monitor, however we saw signals on the central S2, during this run we were adjusting the diode monitor CFD threshold to try and see coincidences with the diodes delayed analogue output on an oscilloscope. So this run is invalid for the diode spectrum,
At 18:40 the DAQ was stopped, run time = 00:47:16
We decided to try adjusting the diode analogue gain on the Ortec 571 amplifier
At 18:40 we restarted the DAQ, again for 5.0MeV 7Li on target CH2 III
- Save name: RData_1/180406174522
- In February 2018 the diode course gain = 50, which corresponded to channel 1000 when no mylar was placed in front of the diode. Now we have 0.9um thick (nominal) mylar in front of the diode.
- During this run we increased the course gain of Ortec 571 to 200
- The delay amplifier was adjusted from 1us to 1.5us, however we saw no difference in the diode spectrum, so this was set back to its original value of 1us
We decided to change over to 7Be beam |