H. Alvarez Pol - NUSTAR Calorimeter WG R3B/EXL Collaboration Meeting - Santiago Sept Geometrical design, simulation progress and first detector test: activities in Santiago de Compostela H. Alvarez Pol - GENP – Univ. Santiago de Compostela INDEX 1 Geometrical design R 3 B constrains First model – Detected problems A second model (ongoing work) 2 Simulation progress 3 First detector test 4 Summary and agenda

H. Alvarez Pol - NUSTAR Calorimeter WG R3B/EXL Collaboration Meeting - Santiago Sept Geometrical design – R3B constrains Some well-known constrains in the calorimeter design: High energy gammas: Energies boosted up to three times the CM energies Large crystals for a high total absorption efficiency High granularity for correcting the Lorenz boost Most energetic gammas in the forward direction Critical region around 35 o (0.5 rad); better polar angle resolution required in a region with very significative statistics! Details on technical note: R3B_CAL_01/05 Available at:

H. Alvarez Pol - NUSTAR Calorimeter WG R3B/EXL Collaboration Meeting - Santiago Sept Geometrical design – First iteration First design iteration (CALIFA 1.2): 6570 crystals in 73 different crystal types Covering polar angles between 7º and 133º Trapezium-like shaped crystals Simple geometry filling the gaps Typical crystal volume: 10x20x( ) mm 3 Weight: ~ 1600 Kg; volume: ~ 360 dm 3

H. Alvarez Pol - NUSTAR Calorimeter WG R3B/EXL Collaboration Meeting - Santiago Sept As we were open to criticism, criticism came soon… Azimuthal gaps between crystals Too many different shapes (types) of crystals, expensive to build Too many channels/crystals… Too heavy, …who is going to hold it during the experiment? Students required Too small crystal section (also affects to the capability to cover the shower in a crystals of few crystals) Geometrical design – Second iteration …so, a second iteration in the design → Irregular crystal shape → From 73 types in CALIFA 1.2 we moved to 10 types in CALIFA 2.0 → Reduction from 6570 to less than 4500 crystals → Ongoing discussion on support systems and crystal wrapping (carbon fibre alveolus?) → Slightly larger crystal section, slightly farther away from the target ( but approx. the same polar angle resolution) CALIFA crystals 10 different types No azimuthal gaps

H. Alvarez Pol - NUSTAR Calorimeter WG R3B/EXL Collaboration Meeting - Santiago Sept Geometrical design – Second iteration

H. Alvarez Pol - NUSTAR Calorimeter WG R3B/EXL Collaboration Meeting - Santiago Sept Simulation progress (first iteration) Simulation: Standalone application (now integrated in R3BSim) Full segmentation (proposal R3B_CAL_01/05 ) 1mm skin [not yet defined] for each crystal Event wise analysis Monoenergetic isotropic gamma emitter Hits defined “per crystal” with references to the primary gamma elements Allows the analysis of pattern recognition methods for the reconstruction of the gamma angles and energies: type 1 (elemental reconstruction) polar angle: from the crystal polar axis of the crystal with larger energy deposited energy: from the sum of all energy depositions in all crystals type 2 (angle by weighted mean) polar angle: from the weighted (energy deposition) mean of the crystal polar axis energy: from the sum of all energy depositions in all crystals type 3 (angle by weighted mean only on 5 crystals) polar angle: from the weighted (by energy deposition) mean of the crystal axis of next 5 crystals around main energy deposition energy: from the sum of the energy deposition on the correlative crystals

H. Alvarez Pol - NUSTAR Calorimeter WG R3B/EXL Collaboration Meeting - Santiago Sept Preliminary results Energy = 0.5 MeV Geometrical efficiency: 84.4% Reconstructed energy peak: FWHM MeV (2.685%) Entries within 3% bars: Mean number of crystal hits per event: 2.27 Analysis type 1 Total events 10 6 Energy = 5 MeV Geometrical efficiency: 80.0% Reconstructed energy peak: FWHM MeV (2.61%) Entries within 3% bars: Mean number of crystal hits per event: 5.95

H. Alvarez Pol - NUSTAR Calorimeter WG R3B/EXL Collaboration Meeting - Santiago Sept First detector test Crystals, APDs, aux. material in our laboratory ready for initial tests: Crystals of CsI(Tl) and CsI(pure) in different geometries: 10x10x10mm 3 10x10x50mm 3  10x10x100mm 3 - October  10x20x200mm 3 (trapezoid) October LAAPD (Hamamatsu) S (5x5mm 2 active area)  S (10x10mm 2 active area) Desiccators, electronics…

H. Alvarez Pol - NUSTAR Calorimeter WG R3B/EXL Collaboration Meeting - Santiago Sept Summary and agenda Calorimeter design: Ongoing iterative design process Second iteration solves initial detected problems Next iteration based on close interaction with engineers (IPNO) Calorimeter simulation Initial simulation for checking the polar angle resolution ready Ongoing work: “realistic” simulation including crystal resolution, wrapping, supports, target, beam pipes… (common R3BSim simulation) Crystal test in Santiago de Compostela CsI(Tl) and CsI(pure) in different geometries ready to be read with APD’s