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.

We looked at the overnight background run (161105_0935_BackgroundOvernight.root), There are gamma-peaks that could be related to neutron inerastic scattering. We identified 565, 596, 608 and 69 keV. They might be related to the effect of neutrons. If this is the correct assignment, this would mean at least some of the neutrons are not thermal when they interact with the germanium. 

There was also significant drift in the Ge gain (seen on the pulser) this may effect the shape of these peaks. 

Some gain drift was also seen on He preamps during this run. The cause is yet to be determined. It is also yet to be determined if these gain shifts are correlated. 

Measurement overnight

Start: around 1:00
Stop: 9:35
File: 161105_0935_BackgroundOvernight.root

The background level after removing the 252Cf source
from the hall dropped to 0.4n/s.

During the night there were neutron rates up to 120 n/s (see figure)

There is a huge spike in the rates which coincides with the time of 
LN2 filling. One can see spike in several spectra (not in all)
One can see also a structure superposed

The rate per rings is also shown. The outer rings see
a higher rate.

Also shown is the comparison of He107 one  (blue) of the outer ORNL2 tubes
with He084 one (red) of the inner ORLN2. The increase in count rate
is about 30%. 

Also shown is the comparison of two external tubes on the top and the bottom:
He107 (blue) and He137 (red), ORNL2 tubes.  There is no increase in count rate.

Also shown is the comparison of a tube above the lead shielding He028 (blue)
and behind the lead shielding He048 (red), UPC tubes. There is no difference.

There is also  comparison between the rate in the CLOVERS and BRIKEN.
Without beam the rate in the Clovers is around  100 g/s against 0.4 n/s in BRIKEN
At the maximum both rates are similar around 130 c/s.

There is also a plot of the gamma-neutron correlation.
We see that there are neutrons which are detected before
the gammas. A possible explanation several neutrons are produced
one is detected first the second later produces a gamma.

Some photos of the elements in the last part of the beam line
during Takechi run.

After the chamber that includes the F11 plastic detector
there are 2 GSI-MUSIC chambers.

In between the MUSIC chambers there is a sample changer 
with 2 Carbon targets of 6mm and 3mm thickness and also
an empty position.

After the 2nd MUSIC there is a plastic detector for testing 
(could be removed at any time)

Afterwards there is the degrader mounted on a separate table.
In the same table there is a 10cm thick lead wall
to protect AIDA during Takechi run.

Mounted on the shielding are from the beam side the top and bottom 
plastic veto detectors.

On the back side the Si detector is mounted.

The hole in the shielding is covered with
a 2cm thick Al plate to protect AIDA during Takechi run. 

Behind AIDA there is a thin plastic detector
to veto the passing through particles.

Beam tuning in BigRIPS

At 19:00 access to Exp. Area was closed and the tuning
of BigRips started.

Unfortunately the 252Cf was left on the table close
to the stairs and cannot be removed until 23:00.

We did a background measurement
Start: 19:00
Stop: 22:18

File: 161104_2218_BeamTuning.root

In the attached figure 1 one can see a plot of the rate
(neutrons/10s) in the BRIKEN detector during this time
The rate was at high as 150n/s during this period.
We estimate that the influence of the 252Cf source is about 15n/s
(corresponds to the lowest rates)

Also attached are pictures of the Top and Bottom plastic veto detectors
mounted just above and below the hole in the shielding.
Interestingly the bottom sees less counts at high energy
and this could be related to the 10cm lead wall raised
before the degrader to protect AIDA that covers only partially 
the top detector.

Also attached is the neutron spectrum for the different rings superposed.
(ROOT color code)

Energy Calibration: See attached pdf

Detector Slope Offset
V2A7C1 0.00155643 0.0842245
V2A7C2 0.000658962 0.78685
V2A7C3 0.00153391 1.198
V2A7C4 0.00157933 0.483094
V2A7C5 0.000704268 0.31553
V2A7C6 NOT THERE
V2A7C7 0.00066837 0.465225
V2A7C8 0.000695872 0.678058





> Energy calibration for clovers, 152Eu
> 
> 
> 
> The Eu source positioned in the center roughly. 
> File name: 161103_1426_152Eu.root

Measurement over night with a 152Eu source inside

Start: 22:48 (03/11/2016)
Stop: 08:26

File: 161104_0826_152Eu.root

Neutron background rate: 0.82 n/s

Geant4 BRIKEN Neutron efficiency calculations as a function of neutron energy and for some spectra: Ga84-vandle, Br88-endf71, Rb94-endf71, Rb95-endf71, I137-endf71, Cf252-MCNPX
  

Calculations for the current BRIKEN detector configuration:

Hybrid mode, 140 counters, assembled in July16.


Summary of files:

BRIKEN_hybrid140.svg  ---> Scheme for the current tube configuration. 

BRIKEN_hybrid140_efficiency.xlsx  ---> Sheet with results of the calculations.

Efficiency_vs_Energy_HybridConf_140b.svg ---> Plot of the neutron efficiency by Ring (see BRIKEN_hybrid140.svg) and total.

We used the laser to align the degrader (see attached photos)

According to the LISE calculation, equivalent effective thickness for 6 mm of Carbon target is 4.5 mm thick Aluminum.

Therefore, we've set the degrader system as follow:

Background measurement for threshold determination



Started at 14:45
Stopped: 16:35

Root file: 161103_1635_bck.root

Energy calibration for clovers, 152Eu



The Eu source positioned in the center roughly. 
File name: 161103_1426_152Eu.root

Check of BRIKEN calibration and thresholds

Source more or less at the center

Online File: 161103_1319_252Cf.root

Start of commissioning preparation


Working directory:
/data/1611Commissioning/161031Preparation/


DACQ configuration file:
161103Conf_BrikenFull.xlsx

Attached the updated excel file. In the first sheet there is the calculator to calculate the efficiency from an given energy.

The Jackel function used is:
Double_t fun=TMath::Exp((par[0]+par[1]*TMath::Log(x[0])+par[2]*TMath::Log(x[0])*TMath::Log(x[0]))*2/TMath::Pi()*
(TMath::ATan(TMath::Exp(par[3]+par[4]*TMath::Log(x[0])+par[5]*TMath::Log(x[0])*TMath::Log(x[0]))))-25.);




> Efficiency calibration
> 
> File "cloversEff.ods" and "cloversEff.xls" contains the experimental efficiency from different measurements
> during July and October
> (G7 broke before Eu-152 measurement). We can assume the efficiency didn't change from July measurements to
> October measurements. 

Efficiency calibration for the D4 clover (data acquired in October).
The attached plots show the parameters for the Jackel function (E[i]=Energy) using the points of 152Eu, 60Co and 137Cs sources.

Roger





> Efficiency calibration
> 
> File "cloversEff.ods" and "cloversEff.xls" contains the experimental efficiency from different measurements
> during July and October
> (G7 broke before Eu-152 measurement). We can assume the efficiency didn't change from July measurements to
> October measurements. 

Efficiency calibration for the G7 clover (data acquired in July).
The attached plots show the parameters for the Jackel function (E[i]=Energy) using the points of a 152Eu source.

Roger





> Efficiency calibration
> 
> File "cloversEff.ods" and "cloversEff.xls" contains the experimental efficiency from different measurements
> during July and October
> (G7 broke before Eu-152 measurement). We can assume the efficiency didn't change from July measurements to
> October measurements. 

Efficiency calibration

File "cloversEff.ods" and "cloversEff.xls" contains the experimental efficiency from different measurements
during July and October
(G7 broke before Eu-152 measurement). We can assume the efficiency didn't change from July measurements to
October measurements. 

From the 252Cf data.

Paper logbook for July-2016
For correct visualization, 
please download it.

Paper logbook for October-2016
For correct visualization, 
please download it.