Endcap design for the
CALIFA calorimeter
Instituto de Estructura de la Materia
CSIC-Madrid
José Sánchez del Río, Carlos Cruz, Ángel Perea and O. Tengblad
1Instituto
de Estructura de la Materia- CSIC
OUTLINE
1.- Introduction: Toward the best end-cap geometrical configuration
OUTLINE
Introduction
Geometries
Optical
simulations
R3BRoot
simulations
Future aims
2.- Different geometries proposed for the CALIFA end-cap
2.1 The trapezoidal prism crystal geometry
2.2 The triangular icosaedrum geometry
2.3 The chamber calorimeter: a R3BRoot geometry
3. An optical geometrical study for optical photons detection
4.-R3BRoot simulations
5.-Future Aims
I
C
INTRODUCTION
OUTLINE
Introduction
Geometries
Optical
simulations
R3BRoot
simulations
The forward endcap must cover the
region between 6 and 44 degrees to
be fixed with the 44-130 polar degrees
of the barrel configuration.
The crystals of the forward end-cap must have a good geometrical
efficiency with a high angular resolution. High energy efficiency must
be considered too (phoswich configuration)
Future aims
Parameters to be optimized for a good geometrical efficiency:
geometry of the crystals and the whole end-cap, weight of each
crystal and the whole end-cap, number of crystals and rings, perfect
fixing (not overlapping), ability to divide the different geometries in
others more simple, cost vs efficiency.
INTRODUCTION
Different geometries proposed for the CALIFA end-cap to obtain a high
geometry resolution
OUTLINE
Introduction
The trapezoidal prism crystal geometry
The triangular icosaedrum geometry
The chamber calorimeter: an R3BRoot geometry
Geometries
Optical
simulations
R3BRoot
simulations
Aim: Reduction of empty space and materials
Different materials proposed for the CALIFA end-cap to obtain a high
energy efficiency
Future aims
22Na
CsI (Na) and CsI(Tl)
(lower energy resolution)
Wavelength:420, 450 nm
Phoswich configuration for
different LaCl/LaBr
crystal lengths
Different reflectors wrappers
Wavelength of max. emission: 350/380
nm
Different geometries proposed
The trapezoidal prism crystal geometry
OUTLINE
Introduction
Geometries
Optical
simulations
R3BRoot
simulations
Future aims
Different geometries proposed
The trapezoidal prism crystal geometry
OUTLINE
Introduction
Geometries
Optical
simulations
R3BRoot
simulations
Future aims
Phoswich configuration
Different geometries proposed
The trapezoidal prism crystal geometry
7+8=15
7+8=15
7+8=15
OUTLINE
Length of each crystal
(LaBr/LaCl) (cm)
Introduction
Number of crystals
456
636
904
Geometries
Total Weight (kg)
302
312
309
Optical
simulations
Number of rings
14
17
21
R3BRoot
simulations
Number of albeoles
114
159
226
Future aims
Angular resolution (deg)
3
2,5
2
Total Price (Phoswich)
30€/cm3
1.997.242 €
2.060.382 €
2.040.194€
Total price (CsI) 3€/cm3
199.274 €
206.038 €
204.019
Less number of crystals, the cheaper the electronics
Different geometries proposed
The triangular icosaedrum geometry
OUTLINE
Introduction
Geometries
Optical
simulations
It can be divided in
different geometrical
figures (crystals), as
many as we want
R3BRoot
simulations
Future aims
We are nowadays
optimizing the different
geometrical parameters
to achieve the best
performance
Different geometries proposed
The triangular icosaedrum geometry
OUTLINE
Introduction
Geometries
Bigger triangular
prisms are made
of smaller ones.
Optical
simulations
R3BRoot
simulations
Future aims
The optical performance
compared with
trapezoidal prisms
seems to be little better
for final optical detection
efficiency. This subject
is under study too.
Different geometries proposed
The chamber calorimeter: a football geometry
OUTLINE
Introduction
Geometries
Optical
simulations
R3BRoot
simulations
Future aims
Five different kind of crystals joined together are proposed: A
regular pentagone (A) and three hexagones, two of them
irregular (C, D) in the ratio of A=11:B=58:C=59:D=26.
Different geometries proposed
The chamber calorimeter: a football geometry
OUTLINE
Introduction
Geometries
Optical
simulations
R3BRoot
simulations
Future aims
We are nowadays
optimizing the different
geometrical parameters
to achieve the best
performance
An optical geometrical study for
detection of optical photons
OUTLINE
Introduction
Geometries
Optical
simulations
R3BRoot
simulations
Future aims
Optical geometry and BPM methods: it looks that the geometries
with parallel faces (and few) have better optical performance
than other geometries with more faces and angular (dif 90 deg)
ones (we suppose that the reflector wrapper reflects light with R=
95% for any wavelength in geometrical optics).
The triangular prism is optically more
efficient than trapezoidal. However the
most optically efficient geometries are the
rectangular prisms, they behave like a
straight channel waveguide.
However this subject is still under study
and LITRANI silmulations must be
developed
An optical geometrical study for
detection of optical photons
OUTLINE
Introduction
Parameters like optical wavelength propagation,
crystal dimensions and geometries, refraction
indexes of the layers (boundary conditions) must be
taken into account in BPM method
Geometries
Optical
simulations
A different reflector wrapper
than the one proposed for CsI
must be considered (different
wavelength maximum
efficiency)
R3BRoot
simulations
Future aims
Rectangular prism
Triangular prism
R3BRoot simulations
OUTLINE
We have been working with R3BRoot under FAIRSOFT and
FAIRBASE
Introduction
Geometries
Optical
simulations
R3BRoot
simulations
We have had problems with visualization macros like the
different eventgenerators in LINUX. Despite of these problems
with loading some classes used for visualization
(FairAnaPairBAse), we have been running R3BSim.C and
R3BAll.C for different simulation parameters.
Future aims
Events can be visualized in MAC computers.
We must dedicate much more time and effort to manage
properly the program. Many questions merge.
Future Aims
Evaluate the different geometries proposed, even in energy as
in optical efficiency vs cost
OUTLINE
Introduction
Find other possible ones and study them to obtain the optimum
crystals to use in the end-cap CALIFA detector
Geometries
Optical
simulations
R3BRoot
simulations
Future aims
Simulate the different nuclear events, specially the one sthat
take place in R3B experiments, with R3B programs (R3BRoot,
R3BSim etc.)
Study the interaction of particles and matter (crystals) to know
the photon detection efficiency of the crystals used (LITRANI)
Compare modellization with experimental results