Transcript Geometry for 10He Experiment based on ROOT

Students*: Dumitru Irina, Giubega Lavinia-Elena, Lica
Razvan, Olacel Adina
Coordinators**: Dr. Slepnev Roman, Dr. Parfenova
Yulia
* Faculty of Physics, University of Bucharest
** Flerov Laboratory of Nuclear Reactions, JINR, Dubna
1)
2)
Creating the geometry of the detectors in
ROOT for efficiency estimates with MonteCarlo simulations
Measurements of dead-layer of the Silicon
detectors used for studies of 8He(t, p)10He
The geometry of the experimental setup is
studied with the example of 8He(t, p)10He
reaction.
The proton telescope consisted of
one 300 μm thick annular Si
detectors
q TheThe
detector.
active setup was in accordance with the theoretical
forhad
thethe
angles of the momentum of the reaction
areaspredictions
of this detector
Zero
angle
telescope
for
products.
The
efficiency
is
important.
We
build
this
geometry
in
outer and inner diameters of 82
8
the He detection
was
installed
order
to
make
Monte-Carlo
simulations
of
events,
wich
would
mm and 32 mm, respectively. The
on the
beam axis at a distance of
permit
us
to
calculate
the
efficiency
of
registration.
proton telescope was installed
25 cm from the tritium target .
100 mm upstream of the target
The telescope included six
and covered an angular
squared (60 × 60 mm) 1 mm
range of 171◦–159◦ in lab system.
thick detectors.
The detector was segmented
The first detector of the telescope
in 16 rings on one side and 16
was segmented in
sectors on the other side. This
16 strips in vertical directions. All
construction serves for identifying
other detectors
the angle and coordinate of the
in the telescope were segmented
particle. With this information we
in 16 strips in horizontal
can restore the full kinematics of
direction.
the reaction.
Silicon detectors were used for the capture
of 8He nuclei. One of their drawbacks is the
presence of a layer at the surface in which the
radiation is partly absorbed but no electric
signal is produced. This region is called dead
layer.
If we know the thickness of the deadlayer, we can determine the energy lost in the
layer and correct the output.
For determining the dead-layer of the detectors, we
used a alpha-particle source in two different setups (0⁰
and 45⁰) and analyzed the spectra obtained
0 Degrees
45 Degrees
The peaks were
shifted and by
measuring the relative
energy shifting we could
determine the thickness
of the DEAD-LAYER.
We have 2 sources
of errors:
*) we approximated the
energy loss trough the
detector to be linear
*) we have a statistical
error for the gaussian fit
(of about 2 channels).
This corresponds to
error of 4%.
 The final geometry
The estimated value for the thickness
of the dead-layer is 2.16±0.10 µm
Thank you for your attention !