U: (Up: 2 RIKEN tubes at 40cm from AIDA)
D: (Down: 12 RIKEN tubes at 80cm from AIDA)
US: (2 ORNL 2" tubes close to the floor at 1.8m from AIDA)
Natural background:
File: 150426_Bckg_1425_1805.root
Rate per tube (n/s): U=0.0071, D=0.0045, US=0.0222
Notes:
-This rate seems quite small but we should remember
that we are underground.
-The fact that U is larger than D could be explained as
related that the amount of PE around tubes is larger.
-For comparison:
BELEN-20@JYFL=0.6n/s (no beam), 0.9n/s (beam)
BELEN-30@GSI=1.2n/s (beam)
BELEN-48@JYFL=1.5n/s
110Zr setting:
File:150501_16111810_110Zr.root
Rate per tube (n/s): U=0.483, D=0.139, US=0.292
Ratio to background: U=68.3, D=31.1, US=13.2
Individual tube distribution:
U1 0.280 D1 0.087 D7 0.084 US1 0.132
U2 0.249 D2 0.092 D8 0.084 US2 0.188
D3 0.083 D9 0.077
D4 0.075 D10 0.070
D5 0.073 D11 0.069
D6 0.065 D12 0.054
Notes:
-There is huge increase of with beam
-The drop of increase with distance is consistent
with either beam induced or decay of implants
110Zr setting:
File: 150501_1733_1900_110Zr.root (actually 02/05)
Rate per tube (n/s): U=0.869, D=0.242, US=0.516
Ratio to 1st 110Zr: U=1.80, D=1.74, US=1.77
Notes:
-We don't quite understand the reason for the near factor two
difference since apparently the settings are the same and beam was
rather stable
In order to investigate the point of origin of the neutrons
we add extra PE covering D5,D6,D11,D12 from the top and
D1,D2,D7,D8 from the front
88Ge setting:
File: 150502_21502333_88Ge.root
Rate per tube (n/s): U=1.271, D=0.349, US=0.706
Ratio to 1st 110Zr: U=2.63, D=2.51, US=2.42
Individual rates:
U1 1.340 D1 0.424 D7 0.402 US1 0.576
U2 1.202 D2 0.446 D8 0.381 US2 0.835
D3 0.408 D9 0.342
D4 0.393 D10 0.315
D5 0.359 D11 0.250
D6 0.275 D12 0.193
Notes:
-One notices a relative drop of rate for D6, D11 and D12
pointing to a source located in the vicinity of AIDA
94Se setting:
File: 150503_1219_1319_94Se.root
Rate per tube (n/s): U=1.267, D=0.349, US=0.717
Ratio to 1st 110Zr: U=2.62, D=2.51, US=2.46
Notes:
-Very similar to 88Ge measurement |