dE detector is mounted onto the back side of the shielding (attached photo: dE_position.JPG)

The detector consists of 26 strips. In this setup, the detector is devided into 2 parts corresponding to 2 readout channels. Each part consists of 13 strips joint together.

Output signal from a high gain channel of preamplifier with 137Cs source is shown in attachment 137CsTest_ac.JPG.;

The white noise is about 2 mV for high gain mode.

We will switch to low gain mode during the experiment.

* note:there is a 200 mV offset due to the characteristic of the preamplifier (see attachment dc.JPG)

... and sashimi (see photo)

The detectors (BRIKEN tubes, CLOVER, VETO detectors, AIDA) 
are mounted, tested and ready for November commissioning,
except beam detectors a Plastic TOF and a Si detector which
will be attached to the PE shielding.
DACQs (BRIKEN, AIDA) are running. The synchronization monitoring
program which was working in June, for some reason is not functioning
properly now and is being worked on (desirable but not required).
The data merger and near-line analysis programs are being worked on.

Installation of BRIKEN PE shielding for beam
related neutrons

The missing metallic pieces needed to mount
the forward PE shielding finally arrive and
we mount it with help of the crane.

The shielding (4 PE slabs + 1Cd-PE slab) has attached 
the support for VETO detectors on the beam side
and for and additional ancillary detector
a large Si detector on the BRIKEN side.
See attached photos.

The distance between shielding and BRIKEN is 40 cm.

Friday, October 14, 2016 21:50
AIDA and BRIKEN-CLOVER run with a common clock.

After installing the shielding and checking electronics
(See next entry)

252Cf source 7.5cm from the center.
AIDA nose aligned with the edge of the clovers hole.

start: 21:50 run number: BRIKEN:15 AIDA:0 
stop : 22:18 run number: BRIKEN:16 AIDA:9

BRIKEN dlt file:252CfWithAida75mmcenter_15 to _16
AIDA file: aidas1:/TapeDate/Sept2016/R41_0 to _9 

Online analyzed data around 30%
Online spec: 252CfWithAida75mmcenter_15_16.root
Configuration file attached.

As previously recorded (81), on Thur Oct 13th, A NIM crate failure caused preamp power loss to the HPGe's. While D4 recovered with nominally the same resolution as before. G7 would not recieve power to the preamps without an alarm from the NIM crate.

It was determined that there was a short along the lines of +12V and Ground , -12V and Ground, and between +-12V.

After removing the Red preamp ribbon cable, the remaining channels (K,G,B) were able to be powered on and found to have a nice resolution of near ~2.3 keV for 661 (137Cs).

During the course of testing, the preamp power distribution box (supplied from ORNL) was seen to have a fault in the +12V light and supply. This was seen by placing this supply in a new NIM bin and seeing that it would also not properly supply preamp power to clover D4 (which had recovered fully).

The consistency in this fault is seen as cause to be suspicious of this preamp power supply. It has been replaced by putting two ORTEC TSA's into a seperate NIM bin and using the standard power supply for D4 and G7.

There was no appreciable effect on noise in any other detector.

Change of main power line for MPOD and CLOVER preamp


Because the incident yesterday with the NIM crate,
we try to separate the CLOVER from the rest of 
the equipment.

So we put the MPOD, which powers the CLOVER but also
the 3He tubes and the VETO detectors, and the preamp
power supply in a different line.

We check if this has an impact on the noise in either
CLOVER or 3He tubes.

We measure with the 137Cs-60Co source:
File: 161014_1241_137Cs60Co.root

After inspecting the spectra we conclude that the impact
is not appreciable.

See figures 

662keV resolution:
D4Black: 3.16keV
D4Red: 2.49keV
D4Green: 3.57keV
D4Blue: 3.40keV

New configuration file: 
161014Conf_BrikenFull.xlsx

Background measurement overnight

Start: 01:17
Stop: 10:35
File: 161014_1035_bck.root

See figure

New BRIKEN energy calibration


We check the 3He tubes energy calibration with 252Cf source
We Found that only one tube He006 was slightly shifted and correct it.

Check measurement:
File: 161014_0113_252Cf.root

See figure

Energy calibration of plastic and NaI detectors


137Cs source placed in the center of the arrangement:
two plastics on top of each other the four NaI
on the sides. See photo.

First measurement:
File: 161014_0015_137Cs_VetoDetCal.root

after calibration check measurement: 
File: 161014_0038_137Cs_VetoDet.root

60Co source: 161014_0047_60Co_VetoDet.root

See figures

ADC ranges at the moment:
Plast: 20 MeV
NaI: 20 MeV

Energy and efficiency calibration

We make calibrations for the remaining D4 CLOVER detector
(No pulser: D4 preamp does not see the pulser input, a single TEST input)

Sources on the cardboard holder, place at the center of BRIKEN



137Cs (Ref:CD393) together with 60Co (Ref:CD395):

File: 161013_2331_137Cs60Co.root



152Eu (Ref:272/09-7011):

File: 161013_2350_152Eu.root



The threshold in Black,Green and Blue is cutting Ba X-rays.

Activity of the sources:
>> 60Co (Ref:CD395): 338.4 kBq (+-3%) measured on 01.07.1990
>> 137Cs (Ref:CD393): 347.9 kBq (+-3%) measured on 01.07.1990
>> 152Eu (Ref:272/09-7011): 10.62 kBq (+-1,9%) measured on 16.03.2010

See figures.

NIM Crate Failure. Lost of CLOVER G7

One of the 2 NIM crates, the one containing the power for CLOVER
preamps went kaputt.
As a consequence the preamp of CLOVER detector G7 was damaged:
G7 was removed

CLOVER energy calibration

Short run with 137Cs and 60Co sources at BRIKEN detector center
to make a new energy calibration

Root file: 161013_1240_137Cs60Co.root

We conected the test input to the pulser, and a new calibration was needed

Root file: 161013_1518_137Cs60Co.root

Scanning of the BRIKEN detector with the 252Cf source 
along the longitudinal axis (Z axis)

Measurements from Z: -42.5cm to 42.5cm with steps of 2.5cm. 

Gamma source close to ORNL2 tube

In order to investigate the origin of the background
component in ORNL tubes extending up to 200keV
we place a strong 137Cs source (D393) in the hole
of He136 close to the tube.

Control measurement (no source): 161012_1200_bck_control.root
With source: 161012_1229_137CsHe136.root

We observe that the induced signals are in the same energy region
as the 3rd noise component. The increase of the rate of signals
with the source is a factor 60.

See figures.

This hints to the origin of this component as due to an increased sensitivity
to gamma-rays (more  material?) or internal radioactivity (gamma,beta) 
of ORNL tubes.

Background measurement over night with CLOVER and VETO detectors

ADC #7 added to crate 1 for veto detectors: V1A7
VETO detectors HV off!

Start: 23:45
Stop: 10:56
File: 161012_1056_bck_noise.root

We see a very strong noise in the BRIKEN spectrum!!!
After some work we find that this was a problem
with configuration file: when editing the file
we put the calibration sheet at the beginning this
provoked a mixing of CLOVER and 3He spectra.

ROOT macro for calculation of neutron rates in the BRIKEN detector

Here a ROOT macro to calculate neutron rates from onlines root files generated DAQ configuration 
160718Conf_BrikenFull_cal5.xlsx (and the later ones).

Setup parameters are indicated at the begining of the macro. An output data file is generated with the rates by counter, ring and ADC. If the input root file is "file.root", the 
output data file is "file.root_data".

Further questions by email to: atarisal@gmail.com


 

Check of Plastic and NaI veto detectors and DACQ settings


Plastic: 10x200x450mm**3, PMT: H1161, HV: -1200V, Anode2
Very small and short signal: width: 20ns, rise: 10ns, amplitude up to 10mV
We decided to put an amplifier to have more flexibility
Amp: Ortec 474 TFA, G: 10xmax, INT=200ns, DIF: 100ns
Signal: width: 200ns, height: 100mV
DACQ Trigger & EFIR: P=2, G:2

NaI: 2"x4"x16", PMT: ?, VD: 1410 (ORNL), HV: +800V
Signal: width: 400ns height: 15mV
DACQ trigger and EFIR: P=20, G=20

File: 161011_2330_PlasticNaI_137Cs.root
File: 161011_2335_PlasticNaI_60Co.root

Photo of the arrangement.
137Cs spectrum of both detectors.

Both COVER detectors are installed in place.
See photos.

Detector D4: left of the beam
Crystal distribution:
BLUE-BLACK
RED -GREEN

Detector G7: right of the beam
Crystal distribution:
BLUE-BLACK
RED -GREEN

Cables connected. Some work on noise minimization.
Resolution improved for D4-Black which was poor 
on July. Otherwise similar behaviour.

See spectra with 137Cs and 60Co sources ta the center.
File:161011_1805_CLOVER_CsCo.root
We are using the calibration from July which
works surprisingly well for all except G7Red
(explains double peak in spectrum)

More checks to be done.

Optimization of ADC thresholds

In order to try to reduce the grass-like background
we make a finer adjustment of individual ADC thresholds.
We make first a control measurement putting the 252Cf source
in the center of the detector (AIDA removed)
Start: -
Stop: 23:55
File: 161009_2355_252Cf_control.root

We then make an adjustment of thresholds one ADC at a time.
We adjusted the threshold so that the very low amplitude noise height
in the spectrum is only a small fraction of the pulser.

New configuration file: 160718Conf_BrikenFull_test02_thr.xlsx

A verification measurement with 252Cf
Start: 01:55
Stop: 02:09
File: 161010_0209_252Cf_newthr.root


And the leave a background measurement overnight:
Start: 02:12
Stop: 07:12
File: 161010_0712_bck_newthr.root

We compare the grass-noise rates now with the rates before threshold adjustment
For that we integrate the BRIKEN spectrum between 900keV and 1.5MeV
The rate before was 0.085 counts per second per MeV
The rate now is 0.039 counts per second per MeV
So the improvement was only a factor 2.

One can try to set the thresholds higher  however with this rate the probability
of having a noise signal in a 0.5ms window after a beta signal will be about 1E-5.

The plots below show the situation before and after.