Detector Details

CALO

The overall size of the Calo is a volume of \(877.5mm¡Á796mm¡Á728mm\). There are no more than 23 rows and 21 columns of crystals which is a \(30mm¡Á30mm¡Á30mm\) cube made of LYSO with density of 7.3g/cm^3^. The crystal arrangement is confined within a sphere which require the sum of squares of sequence numbers in three directions to have a root number no more than 12.285. The gap between crystal is 6.5mm in the X direction and 1.5mm but 15mm when the gap is between the fourth and fifth crystal count from the middle in both side in the ZY direction. There are always an odd number of crystals in each row and they are symmetrically distributed. Although the number of crystals per layer varies due to the spherical constraint, the support structure remains the same. The present version of geometry is lack of the outer shell. The shape of the support structure is a square with the upper two corners cut off. The support structure is made of carbon fiber with a thickness of 21.5mm. The board has slots for each crystal matching the side length of the crystals, with a depth of 20mm. Specifically, in the big gap of crystals two stacked reinforcement brick with dimensions of \(31.5mm¡Á15mm¡Á20mm\) and \(34.5mm¡Á18mm¡Á16.5mm\) is added at every odd column position.

FIT

FIT consists of a top sector and four surrounding sectors. Every detectors are composed of 7 super layers. From outside to inside, each super layer has vertical mat, support structure, and horizontal mat.

In the Top FIT, the vertical mat and horizontal mat within each layer have the same dimensions, measuring 1060.8mm in length, 979.8mm in width, and 1.63mm in thickness.

While in the side FIT, the vertical mat and horizontal mat have different dimensions:

  • The vertical mat measures 1060.9mm ¡Á 587.8mm ¡Á 1.63mm.

  • The horizontal mat measures 979.8mm ¡Á 672.9mm ¡Á 1.63mm.

The support structure is a sandwich, with honeycomb board in the middle, which measures 1060.8mm ¡Á 1060.8 ¡Á 20mm in thickness. The core is wrapped in a carbon fiber enclosure, whose thickness is 0.6mm.two mats and the support structure are closely placed together without any gaps.

In top FIT¡¯s layer there are 10 mats. In side FIT,10 vertical mats and 6 horizontal mat.

An actual mat is consist of optical fibers surrounded by glue. but in the MC model we did not construct individual fibers, but instead used a single cuboid as a replacement. The dimensions of the mats are:

  • In top FIT: dimensions of fibers envelop are same for vertical mat and horizontal mat. It measures 1060.8mm ¡Á 97.6mm ¡Á 1.35mm.

  • In side FIT:

    • vertical mat: 1060.9mm ¡Á 97.6mm ¡Á 1.35mm

    • horizontal mat: 672.9mm ¡Á 97.6mm ¡Á 1.35mm.

With the added thickness of the glue, the mat¡¯s width is 97.8mm. Mats are arranged along the short side of the mat, with a spacing of 0.2mm between adjacent Mats.


layer placement in FIT

In the figure, the space on the two side is reserved for the readout.

PSD

The basic PSD layer arrangement is as follow: psd arrangement For all version of PSD: The envelope size of top PSD is \(\rm{1872mm \times 1872mm \times 60mm}\). The envelope size of side PSD is \(\rm{1749mm \times 1005mm \times 60mm}\). The top and bottom layers are sensitive layer made of scintillators. The support structure is a sandwich structure of 25mm thickness, with honeycomb board in the middle and carbon fiber on both surface. The dimensions is \(1820mm¡Á1820mm\) for top PSD and \(1719mm¡Á975mm\) for side PSD. The thickness of the carbon fiber boards is 2mm, and the thickness of the honeycomb board is 21mm.

tile PSD

For top PSD, from the outside to the inside, there are: layer with \(16 \times 16\) plastic scintillators, support structure layer, and layer with\(15 \times 15\) plastic scintillators.

For side PSD, from the outside to the inside, there are: layer with \(15 \times 8\) plastic scintillators, support structure layer, and layer with\(14 \times 7\) plastic scintillators.

The smallest unit is a square plastic scintillator(BC-408) sheet with a side length of 100mm and a thickness of 5mm. The distance between the centers of the square is 106.2mm in both directions. And the inner square plastic scintillator is in the middle of the four corresponding squares on the outer layer.

long bar PSD

top sector

From the outside to the inside, there are: two overlapping layers with 83 plastic scintillators, support structure layer, and two overlapping layers with 83 plastic scintillators.

The smallest unit is a plastic scintillator(BC-408) with a size of\(\rm{30mm\times1835.4mm\times5mm}\). On both the outer and inner layers, there are 83 plastic scintillators arranged in a two-layer crossed pattern. The gap width of the overlapping layer is 2mm.The width of the overlapping part of the plastic scintillator is 8mm.

side sector

From the outside to the inside, there are: two overlapping layers with 43 plastic scintillators, support structure layer, and two overlapping layers with 77 plastic scintillators.

On the outer layer, the smallest unit is a plastic scintillator(BC-408) with a size of\(\rm{30mm\times1703.4mm\times5mm}\). There are 43 plastic scintillator arranged in a two-layer crossed pattern. The gap width of the overlapping layer is 2mm.The width of the overlapping part of the plastic scintillator is 8mm.

On the inner layer, the smallest unit is a plastic scintillator(BC-408) with a size of\(\rm{30mm\times955.4mm\times5mm}\).There are 77 plastic scintillator arranged in a two-layer crossed pattern. The gap width of the overlapping layer is 2mm.The width of the overlapping part of the plastic scintillator is 8mm.

short bar PSD

top sector

From the outside to the inside, there are: layer with 156 plastic scintillators, support structure layer, and layer with 156 plastic scintillators.

On the outer and inner layer, the smallest unit is a long plastic scintillator with a cross-section of isosceles trapezoid, with a length of 464mm. The upper bottom of the trapezoid is 40mm, the lower bottom is 50mm, and the height is 5mm. The overall structure consists of four columns, each consisting of 39 plastic scintillators with a distance of 47mm. The gap width between the two columns in the z-direction is 1mm, and the overlap part of two columns is 6.7mm.

side sector

From the outside to the inside, there are: layer with 80 plastic scintillators, support structure layer, and layer with 72 plastic scintillators.

On the outer layer, the smallest unit is a long plastic scintillator with a cross-section of isosceles trapezoid, with a length of 430mm. The upper bottom of the trapezoid is 40mm, the lower bottom is 50mm, and the height is 5mm. The overall structure consists of four columns, each consisting of 20 plastic scintillators with a distance of 47mm. The gap width between the two columns in the z-direction is 1mm, and the overlap part of two columns is 7mm.

On the inner layer, the smallest unit is a long plastic scintillator with a cross-section of isosceles trapezoid, with a length of 477mm. The upper bottom of the trapezoid is 40mm, the lower bottom is 50mm, and the height is 5mm. The overall structure consists of two columns, each consisting of 36 plastic scintillators with a distance of 47mm. The gap width between the two columns in the z-direction is 1mm, and the overlap part of two columns is 7mm.

The parallelogram bar PSD has only one sensitive layer on the inner side of the support structure, and the minimum unit is not a rectangular prism. The BC-408 scintillator of it conclude two types: one has a parallelogram shape as the side surface, and the other is trapezoidal. In the direction parallel to the shorter side of the columns, five column are aligned to form a layer, with a gap of 1.5mm between two columns.The parallelogram scintillator has a top and bottom side length of 40mm, while the trapezoid has a shorter side length of 30mm and a longer side length of 50mm. The perpendicular distance between every two side surfaces is 1.5mm.

In the top sector, each scintillator has a length of 362mm and a height of 2mm and perpendicular to Y axis. Each row consists of 42 parallelogram sensors and one trapezoidal sensor. The trapezoidal prism is located in the middle, with an equal number of parallelograms on each side.

In the side sector, each scintillator has a length of 337mm and perpendicular to Z axis, with the other parameters unchanged. Each row consists of 21 parallelogram scintillator and one trapezoidal scintillator. The trapezoidal prism is located as the 7th one from the bottom (aligned as much as possible with the center of the Calo).

The support structure layer is a sandwich structure with dimensions of \(25mm¡Á1820mm¡Á1820mm\). The outer layer is made of carbon fiber (2mm), and the inner layer is a honeycomb board(21mm), with a total thickness of 25mm.

parallelogram bar

SCD

The entire top layer sector requires a volume of \(1702mm¡Á1702mm¡Á124mm\). Each side sector requires a rectangular volume of \(1550mm¡Á910mm¡Á124mm\). The arrangement of the layers is as follows:

  • X direction sensitive layer,

  • PCB board (thickness 0.4mm) + small gap(0.32mm),

  • Y direction sensitive layer,

  • PCB board (thickness 0.4mm)

  • 1mm thick carbon fiber, 38mm thick honeycomb board, 1mm thick carbon fiber

  • PCB board (thickness 0.4mm)

  • Y direction sensitive layer,

  • small gap(0.32mm)+PCB board,

  • X direction sensitive layer.

  • These structures above is repeated with a 36mm large gap.

For every top layer, 8 sensors form a ladder, with a gap of 0.5mm between sensors. The sensitive layers in the XY direction are identical, but facing different directions. 32 ladders are arranged in a square layer format, with \(2¡Á16\) configuration. There is a 30mm gap between each pair of ladders aligned along the longer sides. A 30mm gap is in the middle in the set of 16 ladders and the remaining 14 gaps have a width of 0.5mm, similar to the gap between sensors. The minimum unit sensor is a square thin silicon wafer with a side length of 95mm and a thickness of 0.32mm. For the four sector on the sides, the sensitive layer in which the longer side of the ladder is parallel to the X direction consists of 7 sensors per ladder,18 ladders form a rectangular layer configuration of \(2¡Á9\). The sensitive layer in the Y direction is similar to the X direction, but with 9 sensors per ladder. For Y-direction layer , 14 ladders are arranged in a rectangular configuration of \(7¡Á2\).Except for the different ladder arrangement, everything remains the same.

How to write Geometry

Example: Geometry/FullGeometry/compact/v2022a/psd-det-Sbar-v1.xml and Geometry/FullGeometry/src/psd_geo_Sbar_v1.cc in software

Documentation: https://dd4hep.web.cern.ch/dd4hep/usermanuals/DD4hepManual/DD4hepManual.pdf