Upgrade of the ALICE Trigger Detectors using MCPs

A Large Ion Collider Experiment

Upgrade of the ALICETrigger Detectors usingMCPs

ALICE c© | Astro–Particle Neutrino Physics in Antarctica | 9th January 2014 | Christian Holm Christensen


ALICEOverviewUpgradeNew FIT Detector

Microchannel PlatesReadinessOperationRadiator

FIT — again

ALICE c© | Astro–Particle Neutrino Physics in Antarctica | 9th January 2014 | Christian Holm Christensen 2


Current



Upgrades needed after 2018

I After Long–shutdown II, luminosity will be much higherI ITS/TPC needs faster read-out (ITS more pixel, TPC

switch to GEMs)I MUON needs front tracker (Si-pixel, FMD will disappear)I Trigger needs to be faster and more efficient

I V0 and T0 will disappearI New Fast Interaction Trigger detector based on

MicroChannel Plates.



The Old and New

Current configurationT0 Quartz radiators glued to

PMTsV0 Scintilator slaps

Upgraded configurationFIT Radiators with MCP

backend



So Why Upgrade?

V0I Good performance for pp

I Issues with after–pulses

I Effect centrality (amount of nuclearoverlap) determination in PbPb

I Will increase with luminosity

T0I Poor performance in pp due to limited

acceptanceI Good timing resolution for PbPb (< 50 ps).I Issues with after–pulses

Mediate these issues and unify



Are we ready for MCPs

I Yes! R&D efforts for Mill-Spec hasmade it possible!

I We can get the same or better timingresolution

I No issues with after pulsesI Cost–effective way of extending T0

acceptanceI Commercially availableI Relatively in–expensive (total FIT cost≈ 1.5× 106CHF ≈ 9× 106DKK, 1/3 ofthis for the MCPs)



Operation of MCPI εquantum ≈ 10%

I Typical gain ≈ 105

I 2 cm quartz give≈ 1000 γ/MIP

I Thus, ≈ 107 γ/MIPreach the anodes



Optimize the Radiator

I One solid quartz→light diffuse over entiresurface→ larger gain

I Segmented quartz→light focused in cell→lower gain, betterspatial resolution.



How to FIT

I Simulations show triggerefficiency > 93% forMinimum–Bias pp, and > 99%for peripheral PbPb.

I Plenty of challengesI Exact geometry and

integrationI Radiation hard electronics

(≈ 10 krad for Run III ofLHC)


Upgrade of the ALICE Trigger Detectors using MCPs

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