SN simulation status:
design studies and test of new tracking
Yu.Shitov,ICL
SuperNEMO single module with bars
#SNOVA single module bar design:
all detector: 10 x 10 x 2 m Scin bars: 2 x 10 x 200 cm Scin FWHM: 10%
Other pars: as in basic design
e1+e2 for Se-82 0nbb
Very small efficiency!
Efficiency problem has been solved recently It was not physics, but cuts on vertex origin in X-axis < 5 m in module with X=10m.
New vs old tracking
>3% efficiency improvement in new (catsv2r5p1+nemoraXYv1r4p4) vs old (catsv2r4p2+nemorav1r3p14) tracking!
Bar: 4 m -> 2 m
~3% efficiency lost due to geometry factor
Efficiency vs source length
Strange artefact around 105 cm length (?)
Efficiency*sqrt(M) vs source lengt h
Gain in mass overcome decreasing of efficiency
Do we need sandwich-like bar design simulations?
SN has been
simulated with ideal gamma veto (10cm thickness PS from all sides out of chamber (no intermediate
material between) Results (reported in Valencia-2008)
are not optimistic
from the point of view of multi-module
background tagging.
Gamma veto efficiency for some background
208Tl in 82Se foil
Threshold, keV Eff, %
50 76
100 66
200 56
300 51
214Bi near 82Se foil (+/
6 cm)
Threshold, keV Eff, %
50 32
100 14
200 8
214Bi in gg layer near cell (6/15 cm from foil)
Threshold, keV Eff, %
50 44
100 39
200 22
One need to tag low-energy γ− s with high efficiency. Sandwich- like bar SN can't do it better then ideal detector which is not ideal One need to tag low-energy γ− s with high efficiency. Sandwich- like bar SN can't do it better then ideal detector which is not ideal
Low γ -s to catch
Plans
Sandwich-like SuperNEMO bar design implementation (?). Requires huge amount of work in all chain of SNSW, but what's about benefits?
Implementation of external gammas in snvertex.
Thick (10cm) vs. thin (2cm) scintillators: studies with complex background model.
