kravchuk_8b

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Nov 14, 2013 (3 years and 7 months ago)

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Prospects to
measure
8
B
production


VLADIMIR KRAVCHUK

Laboratori Nazionali di
Legnaro, Italy

EUROnu week in Strasbourg


1
-
4 June 2010

CONTENTS

1.
INTRODUCTION

2.
CROSS
-
SECTION MEASUREMENTS AND PRECISION

3.
ANGULAR DISTRIBUTION

4.
DIRECT OR REVERSE KINEMATICS?

5.
EXPERIMENTAL SET
-
UPS

a) Internal options: LNL
-
TANDEM/CN, Legnaro


i) LNL
-

CN


ii) LNL


TANDEM RIPEN+PHOSWICH SET
-
UP


iii) LNL


TANDEM EXOTIC+RIPEN SET
-
UP

b) External options


i) LNS


TANDEM MAGNEX+EDEN SET
-
UP Catania, Italy


ii) IUAC


15 MV PELLETRON HYRA+NAND SET
-
UP, New Dehli, India


iii) JINR


U400 CYCLOTRON AKULINA+DEMON SET
-
UP, Dubna, Russia


iv) JYU


K130 CYCLOTRON SET
-
UP TO BE STUDIED, Jyvaskyla, Finland

6.
TARGETS

7.
CONCLUSION

1. INTRODUCTION

In the article of Rubbia et al. the
8
B
nucleus is considered as a neutrino
source producing relatively high
-
energy neutrinos:

The reaction proposed for the
8
B
production is:

with the decay time of 0.77 s. In the
same article the plot of the total
cross section of the indicated process
is demonstrated as a function of
3
He
incoming energies together with the
incoming energies for the reverse
kinematics:


The optimum energy for collisions
suggested in the article of Rubbia et
al. is ~20 MeV for Li ions on He
target.

C. Rubbia et al., Nucl. Instr. and

Meth. A 568 (2006) 475
-
487

2. CROSS
-
SECTION MEASUREMENTS
AND PRECISION


and references therein

1. What precision in the cross
-
section measurements is
required for the project?


3. ANGULAR DISTRIBUTION

Angular distribution is measured only until
E(
3
He)=5.7 MeV

2. Presumably there is a need to measure
the angular distribution. What angular
resolution is required? This information
will help in the choice of the set
-
up and
geometry.


3. Do wee need to perform theoretical
calculations (using presumably DWBA
code) for the possible comparison with
the experimental results and for the
extension in the whole energy range of
interest?


4. DIRECT OR REVERSE
KINEMATICS?

D. Neuffer, Nucl. Instr. and

Meth. A 585 (2008) 109
-
116

LISE++ Kinematics Calculations

1)
8 MeV
3
He (16 MeV
6
Li)



intermediate
case;

2)
10 MeV
3
He (20 MeV
6
Li)



optimum
energy according to the articles of Rubbia
et al. and Neuffer;

3)
5.5 MeV
3
He (11 MeV
6
Li)



energy with
the maximum reaction cross
-
section from
the data in literature.


For each of the energy cases described
above 4 calculations were performed:

two
-
body direct kinematics

3
He +
6
Li
-
>
8
B +
1
n
;

elastic scattering direct kinematics

3
He +
6
Li
-
>
3
He +
6
Li
;

two
-
body reverse kinematics

6
Li +
3
He
-
>
8
B +
1
n
;

elastic scattering reverse kinematics

6
Li +
3
He
-
>
6
Li +
3
He
.

4. What projectile energy shall
we use in our measurements?


5. EXPERIMENTAL SET
-
UPS

a) Internal options


LNL, Italy

i) CN / RIPEN array

DIRECT KINEMATICS

-
CN
3
He beam can arrive up to an energy
of 11 MeV (pulsed 2 ns);

-
Part of the RIPEN array could be used
for the neutron detection

-
Non
-
coincident measurement

-
Li target is available

-
Could be considered as a test
measurement


5. EXPERIMENTAL SET
-
UPS

a) Internal options


LNL, Italy

ii) TANDEM / RIPEN
-
PHOSWICH array

REVERSE KINEMATICS

-
TANDEM
6
Li beam is available
around energy of 20 MeV (pulsed
~
1 ns);

-
The RIPEN array could be used for
the neutron detection in
coincidence with the PHOSWICH
array for the
8
B detection

-
The high elastic count rate is not a
problem for the PHOSWICH
detectors

-
The RIPEN array has to be
equipped with the electronic
modules


RipeN

Ri
velatori
pe
r
N
eutroni a LNL

12.7cm x 12.7 cm

24 BC501 cylindrical Liquid Scintillators


Digital electronics
: under test

Acqiris
:
DC271A


1GS/s


4 Ch


8 Bit

RipeN
@
LNL

Ongoing tests

n

g

g

n

n

g

4 MeV p + Li pulsed beam @ CN Van de Graaf accelerator

Sampled signal

ToF

RipeN
@
LNL

Ongoing tests

n

137
Cs

60
Co

88
Y

g


All 24 detectors working!


Good n
-
g

di獣物浩湡瑩潮


Light response


Discrimination threshold

Source Tests



Bit
-

resolution



Sampling rate



Acquisition rate



PSA algorithm
(developed by

T. Marchi)

Preliminary

digitized electronics:

Acqiris card

g

n


-


keVee

g

n

Am
-
Be

PHOSWICH

array at LNL

IMF

(Z
IMF

from 3 up to
~12)


5. EXPERIMENTAL SET
-
UPS

b) External options

i) MAGNEX / EDEN Set
-
up, LNS Catania, Italy

REVERSE KINEMATICS

-
6
Li beam is available around
energy of 20 MeV (pulsed
~
1 ns);

-
The EDEN array could be
used for the neutron
detection coupled to the
MAGNEX array for the
8
B
detection

-
The
target chamber
,
equipped with multiple
entrance ports which are
double
-
valved to allow
rotation of the spectrometer
without breaking vacuum in
the chamber


-
The entrance
position
-
sensitive start detector

(PSD), providing the Start
signal for the TOF and
measuring the particle
angles.

-
The
focal plane detector

(FPD), which identifies the
particles. It measures ion
position, direction (angle),
energy
-
loss, charge and
mass




EDEN Calibration

R. Ghetti et al., Nucl. Instr. and

Meth. A 516 (2004) 492
-
501

5. EXPERIMENTAL SET
-
UPS

b) External options

ii) HYRA / NAND Set
-
up, IUAC New Dehli, India

REVERSE KINEMATICS

Hy
brid
R
ecoil Mass
A
nalyzer
(HYRA)


N
ational
A
rray of
N
eutron
D
etectors
(NAND)


5. EXPERIMENTAL SET
-
UPS

b) External options

iii) AKULINA / DEMON Set
-
up, JINR Dubna, Russia

REVERSE KINEMATICS

DEMON Neutron detection array

5. EXPERIMENTAL SET
-
UPS

b) External options

iv) JYU, Jyvaskyla, Finland

DIRECT KINEMATICS

6. TARGETS

The people of the LNL
-
EXOTIC set
-
up are using
3
He gas targets. The composition of the
target is the following: the 2.2 micron entrance HAVAR (heat treatable Cobalt base
alloy that provides very high strength, Co
-
42%, Cr
-
19.5%, Ni
-
12.7%) window with the
diameter of 16 mm, 5 cm of the gas cell, exit window with the same characteristics of
the entrance one. If we decide to use 5 cm (obviously using a cooling procedure), we
can just borrow one of the existing targets from the EXOTIC set
-
up. In case we want to
use less then 5 cm, we can realize a new target with a guidance of the EXOTIC set
-
up
users. The
3
He gas targets are provided by Padova and the cost of the one is estimated
to be ≤ 5 KEuro.


Schematic drawing of the gas target(s)

7. CONCLUSION

A. Personally we see a more feasible internal option ii) by using the
RIPEN set
-
up at the LNL 3rd experimental hall with the detection set
-
up
consisting of the PHOSWICH array for the
8
B detection in coincidence
with the neutrons detected by the RIPEN array.

B. The choice of kinematics is reverse in this case, ~20 MeV pulsed
6
Li
beam can be provided by the LNL TANDEM accelerator and as a target
3
He gas target (already existing or realized in a decent time) can be
used.

C.

The question here is a timescale, as the RIPEN array should be
equipped with electronics for 24 detection modules.


D. If the timescale for the RIPEN developed is considered to be long, the
internal option i) and external option i) (Catania) could get high priority.