The TIC project: tracking gamma rays with a

calorimeter

Nicola Mori

INFN sezione di Firenze

5th HERD workshop – CERN - 12th October 2017

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Future cosmic-ray experiments

● Requirements for the high-energy frontier:● Acceptance (multi-TeV electrons, hadrons at the knee)● Energy resolution● Collocation in space → constraints on weight and power

consumption

● Innovative designs● Homogeneous and isotropic calorimeter● HERD, CaloCube

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The concept

● Cubic scintillating elements● Accepts particles from 5 sides→ GF*5

● CaloCube prototipe: 5x6x18 CsI cubes● Sensor: 2 photodiodes per cube● Readout: HIDRA chip (2 dinamic ranges per channel)● Tested with particle beams at SPS

● Energy resolution for e- @ 100 GeV ~ 1.5 %

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Towards the design of a complete experiment

● Additional requirements:● Particle ID (→ silicon detectors)● Tracking (and identifcation) of gamma rays

● Multi-messenger approach● Increase of science reach

● “Conventional” gamma tracking● Pair-production telescope with alternating silicon-passive (e.g.

tungsten) layers

● γ →e+e- in tungsten

● Tracking of the pair with silicon detectors

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Issues with charged particles

● Heavy (→ reduced mass budget for the calorimeter → reduced acceptance and en. res.)

● Thick (→ nuclei fragmentation → less precise particle ID)

● Tall (→ reduced overall acceptance)

Calorimeter

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Tacking calorimeter

● Basic idea: use the calorimeter as an active converter

● Insert silicon microstrip layers between the top layers of the calorimeter● Reconstruction of the axis of the e.m. showers induced by gamma photons

● Lightweight (silicon only), low-profle tracker for charged particles● Plus other ancillary detectors (TOF, AC, ...)

Calorimeter

Calorim

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Calor

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Preliminary MC studies

Monte Carlo (FLUKA) simulations of 3 different designs (LYSO cubes)

● A: standard● B and C: thin detector (low energies)

Geometria A Geometria B Geometria C1 GeV 3.62° 2.54° 1.70°10 GeV 0.461° 0.183° 0.101°100 GeV 0.031° 0.029° 0.030°

● Angular resolution (68% PSF) for vertical photons:

Presented by S. Bottai at 4th HERD workshop in Rome on 9th February 2017

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The Tracker-In-Calorimeter (TIC) project

● Realization and characterization of a prototype of a tracking calorimeter for gamma rays● Integrate the CaloCube prototype with spare AMS/DAMPE

silicon microstrip layers● All the components are already in-house

● Test beams with electrons (SPS, BTF) in 2018● No GeV gamma beam available worldwide● Shower axis reconstruction is identical for gammas and electrons● Precise upstream tracking (e.g. conventional silicon tracker)

● Just approved (29th September) and fnanced by INFN CSN5● Kick-of meeting soon

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Outline of the project

● Integration of the CaloCube prototype with spare AMS/DAMPE silicon detectors

CaloCube New structure

Silicon detectors

e- beam

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Description of the project

● Design and realization of a new support structure● With support for silicon layers

● Add thin crystals in the front part● Modular structure for quick thin/thick crystal interchange

● MC simulation and event reconstruction● Assessment of the overall performance

● Especially for inclined particles● Impact on energy resolution

● Algorithm optimization

● Beam tests● Low energy: BTF Frascati (< 700 MeV)● High energy: SPS CERN (~ 30-300 GeV)

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Summary

● Simultaneous detection of charged particles and gamma rays poses serious design difculties

● HERD scientifc objectives require high performance for both particle species

● The design of TIC aims at being a sweet spot and will be studied with MC and beam tests during next year● The project is already approved and fnanced by INFN

● A successful investigation might lead to a viable option for the optimization of HERD