Drawings of the polyethylene neutron moderator and table assembly

A list of the available hardware

START
Assembly and commissioning of BRIKEN neutron detector 

The hybrid configuration of the BRIKEN neutron detector will be assembled at BF2 for the first time with 140 3He
tubes and 2 CLOVER detectors, connected to the Gasific digital data acquisition system and tested with 252Cf
sources.

The activity of the 252Cf source, used for the calibration was 3.7 MBq at 15.05.2006. Unfortunately, uncertainty is missing from the data sheet :-(

We run all the night until the end of beam time, and the Bn correlations are more clear now.

During the 98,100Kr setting run we observe 
in the time correlation plot (middle right panel)
of beta signals (marked by AIDA, with amplitude larger than ch=600)
with Riken 3He tube signals (noise and pulser cleaned) 
a small peak around t=0 which might be indication 
of beta-delayed neutrons.
The spectrum was measured for about 2h.

Screen shot of the rudimentary on-line
analysis of the combined data:
BRIKEN-AIDA-BigRIPS

 
Top Left: dE (from MUSIC) vs. ToF (F11-F7)
Top Right: X-position (at F9) vs ToF

Middle Left: Amplitude spectrum of RIKEN tubes

Bottom Left: Energy spectrum from AIDA marked as beta-decays 

Middle Right: Time correlations between betas (AIDA) and neutrons (BRIKEN)

Bottom Right: Time correlations between implants (AIDA) and neutrons (BRIKEN) 

(the range of time correlated data [-1ms,+1ms])

After the long shutdown the beam is back at 00:30 (06/05)
Intensity is slightly lower 26pnA and somewhat unstable (short time)
Measurement in the morning:
File: 150506_0846_0915_94Se.root
Average rate per tube (n/s): U=3.39 D=0.93B=0.40
Notes:
-The rate has increased by 3.5 in the detectors close to EURICA (!?)
-The rate at the detector below the MUSIC is substantial. 
From the different magnitudes it is clear that neutrons are originated
both outside and inside EURICA.

The Al degrader thickness was reduced to 4.8mm

Beam still down. New background measurement
with new RIKEN tube below the MUSIC chamber 
(call it B)

File: 150505_0040_1130_aprox_bckg.root
Average rate per tube (n/s): U=0.0073, D=0.0065, B=0.0070

Failure of a quadrupole triplet at BigRIPS (some time after earthquake)

We take the chance of measuring background:

File: 150504_1500_2047_bckg.root
Rate per tube (n/s): U=0.098, D=0.0062, US=0.0200
Ratio to 1st 110Zr: U=1.38,  D=1.99,  US=0.90
Notes:
-Compared to the 1st background measurement there are changes
larger than expected statistical fluctuations: 
perhaps due to slight changes in noise

For EURICA measurements degrader thickness were increased
trying to decrease MACI and AIDA trigger rate
Before we had 5.7 mm of Al
Now we have: 
Degrader: 4.0 + 1.0 + 0.6 + 0.4 +0.3 = 6.3 mm of Al
also 2x 0.8mm Al plates were added before 
the MACI start detector (thus covering partially AIDA)
Trigger from AIDA will be taken from 3rd DSSSD

The Lower polyethylene pieces was swamped.

In the photo beam comes from the left.

 New detector placed under the beam line, below MUSIC chamber

This detector replace the USA tubes in the DACQ because we need the preamp to plug it.

AIDA trigger plugged in Mod2 Ch12

We have some new rule about the data taken at RNC from this year.

Shunji

94Se setting:
File: 150503_1500_1554_94Se.root
Rate per tube (n/s): U=0.966, D=0.263, US=0.538
Ratio to 1st 110Zr: U=2.00,  D=1.89,  US=1.84
Notes:
-Compared to the 1st 94Se setting measurement (12:19-13:19)
there is a drop of 25% in the rate without apparent reason

Photos of the general arrangement and details of the new PE blocks