CALOCUBE SVILUPPO DI CALORIMETRIA OMOGENEA AD ALTA ACCETTANZA PER ESPERIMENTI DI RAGGI COSMICI NELLO SPAZIO Call nell’ambito della CSN5 dell’INFN Oscar Adriani, Responsabile Nazionale

PHYSICS MOTIVATION And the starting point for the CaloCube proposal….

Some of the Cosmic- Ray ‘mysteries’ 1 particle / m 2 ×second 1 particle / m 2 ×year 1 particle / km 2 ×year High energy nuclei ● “Knee” structure around ~ PeV ● Upper energy of galactic accelerators (?) ● Energy-dependent composition ● Structures in the GeV – TeV region recently discovered for p and He ● Composition at the knee may differ substantially from that at TeV ● Spectral measurements in the knee region up to now are only indirect ● Ground-based atmospheric shower detectors ● High uncertainties A direct spectral measurement in the PeV region requires great acceptance (few m 2 sr) and good energy resolution for hadrons (better than 40%) High energy Electrons+Positrons ● Currently available measurements show some degree of disagreement in the 100 GeV – 1 TeV region ● Cutoff in the TeV region? Direct measurements require excellent energy resolution (~%), a high e/p rejection power (> 10 5 ) and large acceptance above 1 TeV

Our proposal for an ‘optimal’ CR detector ● A 3-D, deep, homogeneous and isotropic calorimeter can achieve these design requirements: – depth and homogeneity to achieve energy resolution – isotropy (3-D) to accept particles from all directions and increase GF ● Proposal: a cubic calorimeter made of small cubic sensitive elements – can accept events from 5 sides (mechanical support on bottom side) → GF * 5 – segmentation in every direction gives e/p rejection power by means of topological shower analysis – cubic, small (~Molière radius) scintillating crystals for homogeneity – gaps between crystals increase GF and can be used for signal readout ● small degradation of energy resolution – must fulfill mass&power budget of a space experiment ● modularity allows for easy resizing of the detector design depending on the available mass&power

AN INTENSE R&D AND NEW TECHNOLOGIES ARE NECESSARY!

From the idea to the real case A large R&D effort and development of new technologies are necessary to go from the simple idea to a real detector (or better, a real prototype…) The project has a real and strong interest in the CSN2 in view of possible future experiments (GAMMA-400, HERD….) Please keep in mind the importance of the expertise and of the technologies in this field (see DAMPE and GAMMA-400 tracking systems, INFN is receiving money from the space agencies to design and construct the detectors)

The work inside the call - A Optimization of the overall calorimetric performances Optimize the hadronic energy resolution by means of the dual - or multiple - readout techniques Scintillation light, Cherenkov light, neutron related signals Innovative analysis techniques (software compensation) Possible, due to the very fine granularity Development of innovative light collection and detection systems Optical surface treatments directly on crystals, to collect/convert the UV Cherenkov light Dichroic filters WLS thin layers UV sensitive SiPM and small/large area – twin - Photo Diodes New development of front end and readout electronics Huge required dynamic range (>10 7 ) Fast, medium and slow (delayed) signals together New CASIS chip ASIC with integrated ADC

The work inside the call - B Optimization of the charge identifier system - CIS The integration of the charge identifier system inside the calorimeter is a real break through for a space experiment Huge reduction of mass and power Huge reduction of cost Great simplification of the overall structure Thinner size scintillators crystals/Cherenkov radiators Pixel structure Multiple readouts in the ion track Back scattering problem to be carefully studied R&D on the front end electronics to reach: large dynamic range excellent linearity low power consumption

The work inside the call - C Space qualification Basic idea: Demonstrate that such a complex device can be built with space qualified technologies Necessary step for a real proposal for space Production of a space qualified medium size prototype (~700 crystals) Composite materials mechanics Thermal aspects Microcooling technologies to cool down sensors and/or electronics Radiation damage issues

THE ORGANIZATION

The groups involved 1. INFN 1. Firenze 2. Catania/Messina 3. Pavia 4. Pisa 5. Trieste/Udine 2. External institutions 1. IMCB-CNR Napoli  Surface treatments and WLS depositions 2. CNR-IMM-MATIS Catania  Dichroic filters depositions 3. External companies 1. FBK 2. ST Microelectronics

Work Packages WP1: System design, software and simulation, prototype construction Responsible: Oscar Adriani - Firenze WP2: Charge identifier system Responsible: Paolo Maestro – Pisa WP3: Crystals/radiators and optical treatments Responsible: Sergio Ricciarini – Firenze WP4: Photodetectors and electronics Responsible: Valter Bonvicini – Trieste WP5: Beam tests Responsible: Sebastiano Albergo – Catania WP6: Space qualification Responsible: Guido Castellini - Firenze

The WP organizations

FTE in the various INFN RU

Money Matrix