Baby MIND Scintillator modules 11 November 2015 Revision E. Noah

What is in this document? Scintillator module design based on: – latest design of steel module with smaller envelope (not bar size!) for detector modules: was 3.5 m x 2.0 m Now 2.8 m x 2.0 m (actually this is flexible – will see why!) – vertical slab dimensions (decision taken June 2016) – Horizontal slab dimensions (decision taken...) Proposed baseline layout for all calculations from this point onwards 2

3 Baby MIND modules x2 layers horizontal bars x2 layers vertical bars Plastic scintillator Empty space (or passive plastic)

Change of steel plate layout 3500 mm 2000 mm 2800 mm One slit Two slits each 10 mm wide New design Old design 500 mm 4

Steel assumptions Steel procurement: Armco, JFE steel if much cheaper Dimensions for main plate: 3500 x 2000 x 30 mm 3 Slits: Use water jet cutting for slits Mechanical design takes into account: – Slit engineering – Handling, transport, storage – Steel end plate assembly – Detector panel assembly – Protection of coil ends (steel end plates) tested 5

“New” proposal detector panel> 2.8 m for The scintillating plastic fraction of the full detector module should cover as much as possible of the 2.8 m (hor.) by 2.0 m (vert.) central zone: connectors, SiPM, small pcb, cables etc... can occupy space beyond the 2.8 m. Plastic length for horizontal bars will be ~ 2.8 m long, could be a bit more potentially! Aluminium coil Steel end plates Steel main plate Top view 10 mm 50 mm 2800 mm (aluminium coil zone) > 2800 mm (Passive detector panel zone) Electronics 3500 mm (steel plate) 6

Steel + coil Front view Aluminium coil 2800 mm 2000 mm 2100 mm Side view 350 mm Steel end plates (x 4 per main plate) 350 x 2100 x 10 (x4) Steel main plate 3500 x 2000 x

Steel + coil Front view 2800 mm 2000 mm 2100 mm Side view 350 mm Zone reserved for welding coil Zone reserved for handling of steel plate assembly Threaded holes for final alignement onto support rails 8

Steel + coil + detector module Front view 2800 mm 2000 mm 2100 mm Side view 350 mm Detector module plastic scintillator Optical connectors, SiPM, pcb and coaxial cables for vertical bars Optical connectors, SiPM, pcb and coaxial cables for vertical bars Optical connectors, SiPM, pcb and coaxial cables for hor. bars Detector module plastic scintillator zone Electronics cards Electronics 9

Detector module mecanical support on steel module Front view 2800 mm 2000 mm 2100 mm Side view 350 mm Detector module plastic scintillator Optical connectors, SiPM, pcb and coaxial cables for vertical bars Detector module plastic scintillator zone Electronics cards Electronics Precision anchor point for detector module on steel 10 Anchor point for detector module on steel with tolerances for differential thermal dilatation between steel and detector module aluminium frame Support for module bolted to steel frame, between aluminium coil strips.

Key assumptions Mechanical support of detector module will have to be very substantial for ~2800 x 2000 mm 2. Use AIDA experience but revisit completely the mechanical support structure concept that was adopted for the AIDA modules 960 x 960 x 15 mm 3. Keep same optical connector concept as that developed for AIDA, the design has since been improved. Separate the electronics cards from the passive detector panels: This relaxes substantially constraints on transport, handling, and installation. The electronics cards can be shipped separately, and plugged onto the passive detector panels once these have been installed and fixed into position in the B2 pit at J-Parc. Cable trays (SiPM coaxial cables): Vertical vs. horizontal bars: Requirements are different concerning amount of space needed for coaxial cables. we only have max 32 coaxial cables for vertical bars, so cable trays for vertical bars can be just 75 mm wide Match number of channels to multiples of the CITIROC readout chip input channels, x 32. Dimension estimates: – Outer frame dimensions = TBD – Need mm from either end of plastic scintillator bar for optical connectors, photosensors, small pcb and cabling – Vertical bar length: 1950 mm – Horizontal bar length: 2880 mm Full mechanical design will set final dimensions taking into consideration: – machining of plastic scintillators and connectors – integration onto steel modules – cabling constraints for SiPMs and Front End Boards – handling 11

Vertical bars considerations Advantage of new magnetization scheme is that we no longer need two types of vertical bars with two different widths, we just need one! Vertical bars: bars have already been cut by company producing plastic scintillator (August 2015): – 1950 mm length – 210 mm width (to be confirmed by Y. Kudenko for mean values and spread in values) 12

1950 mm 210 mm Fiber bending radius = 30 mm approx. 32 bends 10 mm Baby MIND vertical bar Fiber length = 7000 mm Vertical bars layout: option a) assume: 2 SiPMs/bar R&D required to optimize vertical bars: – how to position grooves – how best to position SiPMs suggestion in sketch for illustration only 13

Vertical bars layout 210 mm 1950 mm SiPM Minimum fiber bending radius = 30 mm 45 mm 15 mm 14 This option is discarded! 1950 mm 210 mm approx. 32 bends 10 mm Baby MIND vertical bar Fiber length = 7000 mm

Vertical bar baseline 15 INR Tests

Vertical bars numbers Per module: – 2 vertical bars layers per module, overlapping: – 8 bars/layer – 16 bars/module – 32 SiPMs/module All modules: – 18 modules – 288 vertical bars does not include 10% spare bars from order of bars 576 SiPMs and corresponding readout channels 18 CITIROC chips 16 To be confirmed with final engineering drawings

Horizontal bars layout assume 2 SiPM per bar left/right R&D required: – is 7 mm thickness ok mechanically over ~3m? – to validate light yield estimates over ~3 m 2880 mm 30 mm SiPM WLS fiber 17

Horizontal bars numbers Per module: – 2 horizontal bars layers per module, overlapping: – 48 bars in first layer – 47 bars in second layer (TBC) – 95 bars/module – 190 SiPMs/module All modules: – 18 modules – 1710 horizontal bars does not include 10% spare bars 3420 SiPMs and corresponding readout channels 108 CITIROC chips 18 To be confirmed with final engineering drawings

19 x2 layers of vertical bars: 8 vert. bars/layer 210 mm-wide bars 45 mm overlap between bars of different layers Plastic scintillator Empty space (or passive plastic) 210 mm37.3 mm135.4 mm mm Overlap between bars of 2 layers Gap between bars on 1 layerEnd gap layer# mm End gap layer#2 Bar width 2760 mm 1950 mm

Distribution of detector modules amongst magnetized steel plates 20  18 detector modules  33 steel plates  not all steel plates can be instrumented 10 Alu. coil = 5 mm thick + 5 mm insulation Slit in Fe 50 detector module: 31 mm thick: mostly plastic scintillator 4 layers x 7.5 mm 2 envelopes x 0.5 mm (carbon fiber) steel module: 50 mm thick: 30 mm Fe 10 mm Al 10 mm insulator + gaps = 60 mm including tolerances! For illustration only! In practice, there are gaps between adjacent bars on one plane!

Layout i): standard momentum measurement 21 [s1-3][s4][s5][s6][s7-8][s9-10][s11-12][s13-15] d1 d2 d3 d4 d5 d6 d7 d8 d9 d10 d11 d12d14 d13d15 d d d: detector module s: steel module [s19-21][s22-24][s16-18][s25-27][s28-30][s31-33] d17 10 Thicker steel to better resolve angular deflection by B-field from angular deflection by M.S. Gaps to improve angular resolution with “lever arm” Thinner steel here to improve cross-calibration of detector: i.e. momentum resolution by range vs B-field (E loss = 35 MeV in 30 mm of steel for MIP  ) Note 1: d0 is smaller since it has to fit closeto (right up against) WAGASCI neutrino targets Note 2: this layout will definitely evolve!! Note 3:... must integrate all WAGASCI sub-detectors! 500

Summary Horizontal bars Vertical bars Total (hor. + vert.) Plastic scintillators # bars per layer48/47856 # bars per module # bars total Readout per module # SiPMs per module # CITIROC per module617 # Front End Boards per moduleTBC Readout total (18 modules) # SiPMs total # CITIROC total # Front End Boards totalTBC 22

Back-up 23

Vertical bars layout: option c) – investigate potential for “blinding groove” to improve spatial resolution 210 mm 1950 mm Blinding groove SiPM WLS fiber 24