IFR detector mechanics W. Baldini on behalf of the Ferrara IFR Group XXVII SuperB Workshop and Kick off Meeting Isola d’Elba May 28 - June 02 2011

IFR Baseline Detection Technique Plan to re-use BaBar IFR structure, adding iron to improve μ-ID Extruded Scintillator as active material to cope with higher flux of particles Minos-like scintillator bars readout through 3 WLS fibers and Silicon Photo-Multipliers (SiPM) 82 or 92cm of Iron interleaved by 8-9 active layers (under study with simulations and testbeam) Two readout options under study: Time readout (TDC-RO) barrel Binary readout (BI-RO) endcaps Minos like scintillator bar + WLS fibers SiPM

Readout Options Time readout Option (TDC-RO): the hit bar gives the first coordinate while the signal arrival time provides the second measure the 2 coordinate at the same time 1ns time resolution  ~ 20cm need TDC readout for each channel relatively simple to be constructed res~20cm Binary readout Option: (BI-RO): the two coordinates are given by two planes of orthogonal scintillator bars: high combinatorial simpler (and cheaper) electronics more complex construction Both option are being tested on beam thanks to a full depth prototype

Mechanics for the TDC Readout option The baseline option for the Barrel is the TDC readout: Outermost layer ≈ 400cm x 400cm Innermost layer ≈ 200cm x 200cm Scintillator bars 2x4x400 cm3 3 fibers each scint. bar SiPM on both sides The active material has to be protected and light shielded, keeping a max thickness of ≈ 23mm For the innermost layers, due to the very high neutron flux, the SiPM will not be inside the module Weight of a module 4m long and 10 scint. bars: ~ 40Kg, but not self sustaining Proper moving/installing tools have to be built

Mechanics for the TDC Readout option The basic idea is to prepare an aluminum box (0.5mm aluminum foil) fix on it the scintillator bars (fibers already glued and polished) Couple the fibers ( 5 cm longer than the scintillator) with the SiPM

Mechanics for the TDC Readout option The PCBs supporting the SiPMs would be fixed on the bottom side of the box on a kind of “rail” This to avoid too many holes in the box (to improve the light tightening) The signal cables will be connected to the PCBs through 90° connectors All the signal cables will be bundled and routed through a single hole (~ 10 cables) rail

Mechanics for the BI-RO Readout option The mechanics for the BIRO option is more complex since the SiPMs cannot be simply put on scintillator’s ends (no space) Two layers of orthogonal 1x4(?)x400 cm3 scintillators: For the longitudinal scint. bars we can basically use the same technique as for the TDC option For the orthogonal scint. Bars a special routing for the fibers has to be investigated A first idea is to bring out the fibers orthogonally, in a large grove (≈2mm deep) which would house the fibers for the whole plane The outermost layers could be made of 4 separated modules (to reduce fibers length) The X and Y planes could be in separated modules (but the total thickness has to be < 23mm) Barrel

Mechanics of the Endcaps For the endcaps the baseline option is the BIRO readout mechanics is easier since there are less constraints Here the modules are not rectangular so the aluminum boxes have to be properly shaped Also here the issue willl be the shielding of the SiPM Module 1 Module 1

Detector related Mechanical Activities Aside to the active layer mechanics there are many other mechanical activities to be carried out Tooling for the scintillator-fibers gluing (embedded holes or surface groves) Given the non self sustaining structure of the active layers (aluminum foils very thin) a set of toolings have to be designed and built: Supports to move the modules during the assembling and QC Toolings for the movements and insertion of the modules in the flux return during the installation phase Other tooling… QC related toolings

Conclusions and next steps The mechanics of the active layers is under definition A present these are “conceptual” designs, we are now going through the details toward a “technical” design Due to the high neutron flux an open issue is where to put the SiPMs of the innermost layers of the barrel It would be desirable to put the SiPMs in accessible points, but this implies to use longer fibers… We could consider the use of a few meters of clear fibers, in this case a proper coupling has to be done Aside to the mechanics of the active layers there are all the tools for the moving, QC, and installation