  We present the design of the mechanical structure of the miniBeBe detector, a
subsystem of the Multi-Purpose Detector, soon to enter into operation at the
Nuclotron based Ion Collider fAcility of the Joint Institute for Nuclear
Research. The miniBeBe detector was designed and is currently being developed
by the MexNICA Collaboration to contribute to the level-zero trigger of the
Time of Flight. The mechanical structure meets the requirements of minimizing
the material budget and be free of ferromagnetic materials, without
compromising its robustness. The design also allows easy module replacement for
maintenance and overall removal at the end of the first stage of the
experiment, without affecting the rest of the subsystems, to leave room for the
installation of the Inner Tracking System. In addition, a Finite Element Method
analysis of the mechanical components under load was performed. Based on this
analysis, it was determined that the design meets the space constraints within
the Multi-Purpose Detector, as well as a deformation of less than 1 mm with
overall stress of less than 2 MPa, such that no material used in the design is
at risk of mechanical failure during operation. A cooling system heat transfer
analysis was performed showing that the detector Silicon Photo-Multipliers can
be kept within a temperature range of 19$^{\circ}$C to 23$^{\circ}$C, which is
adequate for their optimal performance.
