1. Alain Blondel Neutrino Experiments
A Baby-PRISM?
Preamble:
The nuPRISM concept allows to create a ‘monochromatic’ beam by linear combination of a variety of off-angle neutrino beams.
This allows a clear determination of the ‘energy response function’ between
the true neutrino energy and the reconstructed energy.
This is unique and cannot easily be done in a wide-band beam.
I would like to share with you what is at this point a mere idea for a ‘Baby-PRISM that could fit in ND280 and could end up forming a valuable back-up solution
-- if needed
-- and if we can convince ourselves it can be done
Alain Blondel Neutrino Experiments

2. Alain Blondel Neutrino Experiments
The INGRID cross- spans from -1.4 to degrees
in both directions.
It cannot be expanded side-ways but it is possible
to expand it upwards, by at least another 2.8 degrees,
i.e. up to 4.2 degrees.
We can think of a baby-PRISM that would extend
from around 1.4 degrees up to 4.2 degrees.
 Excuse the prespective!
No precise location has been discussed at this point
What is the range of angles that is really needed?
What is the effect of the slightly fuzzier chromaticity
of a PRISM that is closer to the target? ?
Alain Blondel Neutrino Experiments

3. Alain Blondel Neutrino Experiments?
Alain Blondel Neutrino Experiments

4. Alain Blondel Neutrino Experiments
The size is approx. 3x3x12m
What can we do?
Not water Cherenkov.
A wagasci-like detector, higher? ?
Alain Blondel Neutrino Experiments

5. Baby-MIND
+ more
>2 ton target
Magnetized MRD
(Baby-MIND)

6. Alain Blondel Neutrino Experiments
Alain Blondel Neutrino Experiments

7. Alain Blondel Neutrino Experiments
Imagine something like this:
(not to scale)
H x d x w
10x2x0.5 H
dep
wid
vol m
SMRD 10 2
0.5 80
DMRD 1 3 30
240
Wmod
Smod 5
total
400
+15
Muon detector is making all
the mass!
Alain Blondel Neutrino Experiments

8. Alain Blondel Neutrino Experiments
Event estimates:
At 2.5 degrees, with 1 ton (fiducial) in each of FGD1 (CnHn) and FGD2 (~40% H2O)
we have now about 15k events in each
for an exposure of p.o.t. (10% of nominal, 5% of T2K-II, a few % of HyperK)
We are talking about 300k events in the 2.5 degrees module probably <106 total
Or about 104 electron-neutrinos for the measurement of e/mu cross-sections.
-- with careful construction of the FGDs the error on the H2O/CnHn is 2.3% (stat) +1.5%(syst)
(Enrico Scantamburlo, TN in preparation + PhD thesis)
-- Wagasci is 79% H2O, the errors should decrease accordingly by factor ~
Q1: Do we need water targets or is pure scintillator OK?
(can be made potentially more sensitive to vertex activity, easier to gadolinate, etc…)
Or do we keep a combination as in present WAGASCI?
Q2: do we want to magnetize the iron (cheaper than iron itself!) for antineutrino run.
Alain Blondel Neutrino Experiments

9. Alain Blondel Neutrino Experiments
Alain Blondel Neutrino Experiments

10. Alain Blondel Neutrino Experiments
Conclusions
1. This is all very new (~1 week). We may end up laughing.
2. I propose to investigate the possibility of a baby-PRISM that could be located
in ND280 as a back-up solution to an intermediate detector location.
3. It looks as if there should be space.
4. as for the TITUS study, the iron being outside and denser, it will generate
most of the weigth -- and a lot of cost.
However it is not very expensive to magnetize and allows muon measurement and
charge separation.
Alain Blondel Neutrino Experiments