Some info on ancillary detector signals
Plastic veto detectors (Top and Botomm):
The dynode signal of the PMT is passed through an
ORTEC 474 TFA amplifier before going to the DACQ
TFA: Gain=6 x min(~x2), Tint=200ns,Tdif=100ns, NonInvert
DACQ channels: Top: V1A7C1, Bottom: V1A7C2
Photo of the signals of both detectors attached
with 60Co source (with gain changed to 20 x max(~x12.5))
200ns wide 70mV high signal
With this info a rough calibration was established:
for the 2V range an ADC unit is 2000mV/16384=0.122mV
the 70mV (~1MeV) correspond to 574 ADC units which
with the change of gain 6*2/20/12.5=0.048
become 27.6 ADC units. We checked with Gasific
that roughly 1 ADC unit corresponds to 2 EFIR units
thus the calibration is 1/2/27.6=0.018 MeV/unit
NOTE: the calibration in online spectra taken
before noon Sunday 6 was wrong by a factor 2
too large!!!!
Si detector (Top and Bottom halves):
Signal from preamplifier in the low gain mode for the measurement:
we see nothing on the scope with 60Co source. In the high gain mode
we saw the other day a negative 6microsec wide 1mV high
signal with a 60Co.
AIDA plastic veto:
The signal from the PMT is going through a CAEN
shaping amplifier. The signal has a bipolar shape
with a rise time of 500ns a total width of 2microsec
and a height of 100mV (60Co)
F11 ToF plastic (Left and Right):
The signals are processed in the same way that the
plastic veto detector with TFA using the same settings.
Polarity of the signal unknown.
Currently we see no signal seems its not connected.
We found later that the NIM crate where the
TFA were sitting was not on!
We just made a calibration with beam particles
LISE was used to estimate an energy loss of 65 MeV for the ions. |