Simulations and Analysis to optimize the design for the Mu2e ECALgarutti/Talks/Simulation_and_Test_4... · 2012-04-20 · Detailed simulation LYSO crystals: shower profile Intrinsic

Simulations and Analysis to optimize the design for the Mu2e ECAL

Short notice

Alessandra Lucà April 20, 2012

Outline ECAL for the Mu2e experiment

Detailed simulation LYSO crystals: shower profile Intrinsic energy resolution

Test beam @ Mami MC simulation of the prototype Data/MC comparison

Reconstruction Capabilities Clustering & Trigger algorithms

Summary

April 20, 2012 Alessandra Lucà 2

Standalone Simulation (Geant4 )

Data Analysis (Root)

Mu2e fmw Simulation (Geant4 )

April 20, 2012 Alessandra Lucà

The Mu2e experiment

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Look for 105 MeV e-

Al atoms capture µ

GOAL: Detect charged lepton flavor non-conservation in the coherent, neutrinoless conversion of a muon to an electron in the field of a nucleus with a single event sensitivity (SES) of 2 × 10−17 and to set a limit of 6 × 10−17 at 90 % C.L.

N e Nµ − −→

n p n

p

n p n

p n p n p n p

n p n p n p n p

n p n p n

μ

Coherent Conversion

Al27

e

Nuclear Recoil

Ee = mμ– Nrecoil- (B.E.)1S =104.9MeV

Alessandra Lucà 4 April 20, 2012

Beam Direction

ECAL Requirements and Capabilities

Energy Resolution < 5%

Time Resolution < ns

Spatial Resolution ≤ cm

Radiation Dose ≈ 200Gy/y

Magnetic Field 1 T

Trigger Rate 1kHz

30m

m

Single LYSO Crystal readout by APDs

12 crystals

44 c

ryst

als

Calorimeter Vane

The ECAL for Mu2e

The integral of the fitting function. Fitting function integral.

About 95% is within 3.5 RM (~ 7 cm)

Alessandra Lucà 5 April 20, 2012

Lateral and longitudinal energy profiles

Simulated calorimeter was made of 20 concentric tubes (0.5 RM thick). Length set to 28 X0

MC program has been implemented using GEANT4 to simulate the response of a LYSO crystal calorimeter to a 105 MeV electron.

Calorimeter has been divided into 56 slices along z-axis, each 0.5 X0 thick. Cylinder radius has been set to 10 RM

Average energy fraction deposited in the calorimeter,

Standalone simulation of a short Mu2e vane


Standalone simulation studies to evaluate all components affecting energy resolution

1) Leakage (lateral, longitudinal, albedo) 2) Photostatistics and noise Intrinsic energy resolution of about 1.5%, mainly affected by albedo.

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The prototype consists of

1) an inner matrix of 9 crystals (new LYSO SICCAS)

20x20x150 mm3 --> 10x10 mm2 APD Hamamatsu S8664-1010 2) An outer matrix, for leakage recovery, composed of 8 PbWO4 crystals of mixed dimensions: 30(40)x30(40)x130 mm3

readout by PMTs.

3) The transverse matrix coverage is 2.8 RM.

Test Beam @ MAMI: Layout of the prototype

Lyso 13 cm

Lyso 13 cm

Lyso 13 cm

PbWO

13 cm

PbWO

13 cm PbW

O 13 cm

PbWO

13 cm

PbWO

PbWO

PbWO

PbWO

PbWO 13 cm

PbWO PbWO

PbWO

PbWO

PbWO

PbWO

PbWO

PbWO

PbWO

PbWO

PbWO

Lyso 15 cm

Lyso 15 cm

Lyso 15 cm

Lyso 15 cm

Lyso 15 cm

Lyso 15 cm

Lyso 15 cm

Lyso 15 cm

Lyso 15 cm

∼2.8 Moliere radii

1 inch PMT

APD 10x10

Lyso 13 cm

PMT: 0.6 cm

Alessandra Lucà April 20, 2012 7

The test beam has been carried out at the Mainz Microtron (MAMI) facility_ Germany _ in March 2011

MC Simulation

Complete Geant-4 simulation respecting all the construction features of the matrix: dimensions, positioning, photosensors (p.e., noise), 300 μm Tyvek wrapping, beam dimensions (8 mm Ø).

Photon transportation has not been simulated, because of CPU limits.

LRU simulated a posteriori


Data/MC comparison


MeV/Ebeam

MC • Data

Erec/Ebeam

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Erec/Ebeam Erec/Ebeam

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Erec/Ebeam

Data-MC comparison:Esum/Ebeam and σE/E

April 20, 2012

Erec/Ebeam

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Erec/Ebeam

INNER MATRIX

WHOLE MATRIX

Energy Sum in the inner and in the whole crystals matrix at 100 MeV

INNER MATRIX

WHOLE MATRIX

Alessandra Lucà 10

Mu2e framework:Event display (1)


Event Display for a pure single event.

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Event display (2) Zoom: additional energy deposits coming from background Clustering

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Clustering

Each cluster is reconstructed joining contiguous crystals around the cell with maximum energy deposition. From differential time distribution ∆(t), one knows that different clusters can be merged within a time window of 1 ns. In such a way, the fragments are recovered, improving energy resolution.

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Trigger algorithm: energy distribution on front face

90700 generated events with cosTheta(-0.5:0.5) and 20 hits in the Tracker: 61500 (70%) events on the Front Face and 27500 (30%) events on the Edges Assuming to be able to discriminate DIO from signal, on both ECAL places Effi ~ 98%

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Rate for 6 batches 91% efficiency @ 64 MeV DIO Rate reduction of 120: 600 kHz 4 kHz in Standalone Trigger Mode. Rejection/efficiency depends on energy resolution

Trigger: summary

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Simulations and Test to optimize the design for the electromagnetic calorimeter: • Standalone GEANT4 Simulation of LYSO crystals matrices ->

Detailed energy profiles for the radial and longitudinal energy deposition and leakage have been presented. The intrinsic resolution has also been shown.

• Participation @ MAMI Test Beam and Data Analysis of obtained

results with a prototype. • Detailed simulation of the prototype -> Data / MC comparison.

• Reconstruction Algorithms to test the ECAL capabilities with a full simulation of signal and bkg events in the Mu2e Framework software (among them I’ve shown simple clustering and trigger procedures)

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Summary


Backup

µ-N→e-N and µ+→e+γ

κ<<1 magnetic moment type operator µ → eγ rate ~300X µN → eN rate

κ>>1 four-fermion interaction µN → eN rate many orders of magnitude greater than µ → eγ rate

Model independent

CLFV Lagrangian:

MEGA SINDRUM II

MEG goal

Mu2e goal

∑=Λ+

+Λ+

=duq

LLLLL qqeFeRm

L,

22 )1()1(µ

µµνµ γγµ

κκσµ

κµν


New Physics scenarios for the μ --> e conversion

From W. Marciano. also see Flavour physics of leptons and dipole moments, arXiv:0801.1826


Cos’è la conversione µ →e ? La conversione coerente, senza neutrini, di un muone in elettrone a seguito di

cattura su nuclei è un esempio particolarmente interessante di un processo di LFV, nel settore carico.

Il μ- viene frenato su un bersaglio dove dà origine ad un atomo muonico, e giunge allo stato 1s

1. Cattura (≈60% Al)

2. Decadimento in Orbita (DIO) (≈40% Al)

3. Conversione coerente:

Un singolo elettrone monoenergetico. Ee = mμ – B.E. = 105. MeV (Al)


'N Nµµ ν− →

eN e µµ ν ν− −→

N e Nµ − −→

56( ) 10SMBR N e Nµ − − −→ ≈

Nel Modello Standard tale conversione può avvenire con un rate al di sotto dell’attuale portata di qualunque esperimento.

X e-

Coherent recoil of nucleus

µ-

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L’obiettivo di Mu2e


La collaborazione Mu2e ha proposto un esperimento da svolgere al Fermilab (tramite produzione di ca 1018 muoni in due anni) con l’obiettivo di osservare il processo in esame, o di ottenere un upper limit di:

Mu2E sensitivity is more than 4 orders of magnitude

beyond the current limit

Il migliore limite è stato ottenuto da SINDRUM II (‘90).

Normalizzato alla cattura: Il muone giunge all’orbitale 1s con transizioni e.m. (X-rays danno lo stop rate, tramite un rivelatore al germanio situato vicino al beam dump). Dopo la cattura Mg → Al by a 2.6 MeV β followeseguito da γ che potrebbe essere usato per il rate di cattura

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Pulsed beam

105 MeV electron delayed

Al foils: muon convert

here

Prompt!!!

Pulsed beam reduces prompt bkgs

8 GeV protons produced by the Fermilab accelerator


Backgrounds • Muon Decay In Orbit (DIO)

- High resolution in order to avoid this kind od bkg • Radiative pion capture • Radiative muon capture


Back

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Prompt Background and Choice of Z

chosen Z based on tradeoff between rate and lifetime: longer lived reduces prompt backgrounds

Back

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Transverse-tracker

Beam Z

18 “stations” spanning ~3 m length

• 18 stations • Each station has 2 planes … 36 planes • Each plane has 6 panels … 216 panels • Each panel has 2 layers … 412 layers • Each layer has 50 straws …

21,600 straws • Two readout channels per straw …

43,200 readout channels

6 Panels 60° rotation

The tracker momentum resolution for 100 MeV electrons is about 300 keV and is

dominated by multiple scattering in the tracker.

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Light Yield del NaI ∼ 40000 γ/MeV

Crystals for HEP (High Energy Physics)


CR test (Inner Matrix) - Calibration CR test for the equalization of response carried out (T~ 24 C) by triggering with an external scintillation counter on top of the prototype. clean-up the events by selecting “clean” fired columns for the inner matrix. Calibration of the single channel at a level of 2% M(APD) ~ 120 Average MIP ~ 100-120 counts

No energy in the lateral columns


Back

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Noise test of the matrix

We summed the charge of the 9 LYSO+ APD crystals. Same thing done for the 8 PBWO+PM of the external matrix (1) Overall NOISE LYSO ~ 3.2 Counts. (2) Assuming MIP~ 100 Counts

σ(noise) = 3.2*20 MeV/100 = 620 keV

Excellent scaling with √(Nch) ~200 KeV single channel noise

Overall PBWO+PM noise ~ 2 counts We have a total 3.6 counts, 720 keV of noise.


Back

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Linearity

Total energy deposit and beam energy Ratio

Inner matrix

Whole matrix


Position Reconstruction

Position Scan aloong X Δx=5mm, X0=-1.7mm

Energy Resolution along X

April 20, 2012

Orizontal Scan : energy reconstruction

Alessandra Lucà 30 30

Disuniformity contribution to energy resolution

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Source of calibration

19F + n → 16N + α 16N → 16O* + e− + νe 16O* → 16O + γ (Eγ = 6.13 MeV)

Activated Fluorinert is pumped through tubes into crystals (ECAL front face).

Source : FluorinertTM FC-77 (C8F18) Decay process:

t1/2 =7 s

Neutron produced by a DT generator. d + t → n(14.2 MeV) + α Rate =109 n/s


A typical energy spectrum measured in a calorimeter can be approximated by the Logarithmic Gaussian function [Di Claus Groupen, Schwartz, “Particles Detectors”, Cambridge University Press (2008)]

Logarithmic Gaussian function


Particle ID

Muons not stopping in target can have momenta up to 100 MeV (~ 10-4)

Muons deflecting up to 30/40 degrees could mimic a conversion electron

Fortunately they are “prompt” m.s. in 17 targets below 10 degrees Probability of large deflections by elastic

scattering?? P ~ 10^{-3}

1) mu- response on the EMC with Geant4 2) Activated Atomic and Nuclear Captures 3) X-checked endpoint and DIO fraction on Al, gold, Pb 4) X-checked calculation of EndPoints 100 k events with mu- impinging on a Standalone matrix of LYSO crystals

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Test beam @ Mami

Dopo un primo test effettuato nel 2009 @ BTF( Beam Test Facility dei LNF) con un prototipo più piccolo, abbiamo costruito una matrice prototipo di dimensioni più grandi per testarla con un fascio di fotoni @ MAMI (Marzo 2011).


Nella sala A2 il fascio di elettroni viene convertito in un intenso (~108 γ sec-1) fascio di fotoni reali attraverso bremsstrahlung in un sottile radiatore (foglio metallico). Il momento degli elettroni scatterati in questo processo viene analizzato da uno spettrometro costituito da uno scintillatore plastico che fornisce una misura dell’energia del fotone associato per bremsstrahlung con una risoluzione di pochi per mille. Fascio di fotoni taggati con

eccellente ∆P(FWHM) = 1 MeV Rate selezionabile (da pochi kHz fino

al MHz) & energia nell’intervallo 20-380 MeV

Spot del fascio di fotoni sul calorimetro di ~ 8 mm di diametro

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Assemblaggio della matrice: cablaggio dell’elettronica


Assemblaggio della matrice: ermeticità & cablaggio


ADC Count

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Scan in Energia

QTOT =Qi − Pi

Mi

M

i∑

• Dopo aver calibrato i canali con le particelle al minimo (MIP) ed aver effettuato i run di piedistallo sono state selezioante 11 energie tra 40 e 300 MeV.


MeV/Ebeam

MC • Data

Data/MC comparison

April 20, 2012 Alessandra Lucà Erec/Ebeam

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Erec/Ebeam

▪ MC ● Data

Data/MC comparison (external matrix)


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Trigger & Cluster

Un algoritmo (filtro ) di Trigger è necessario per: (i) ridurre la scrittura su disco di una grande quantità (100-300) in modo da portare i 300 PB/year a O(PB) storage (ii) oppure ridurre il il flusso di Dati dal rivelatore da 30 GB/s pochi 100 MB/s Il FILTRO dovrebbe essere efficiente O(90%) per eventi di segnale.

L’ EMC puo’ svolgere tale ruolo. Il punto (1) puo’ essere ottenuto anche a livello di FPGA del DAQ per avere maggiore flessibilità. 100 k eventi (Signale+DIO) simulati nel Framework + un semplice algoritmo di clustering usato per unire celle contigue. - cluster divisi in due zone: Front Face or Edges. - raggio interno dell’ EMC @ 390 mm. - studio in funzione della risoluzione energetica dell’EMC.

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Event display (2)


Event Display per un evento tipo: segnale + fondo I fondi prodotti dalla cattura creano segnali spuri sul tracciatore che possono inficiare la ricostruzione della traccia

Blue text: beam related. 44

Documents

Simulations and Analysis to optimize the design for the Mu2e ECALgarutti/Talks/Simulation_and_Test_4... · 2012-04-20 · Detailed simulation LYSO crystals: shower profile Intrinsic