Intelligent Low-level Signal Detection and Zero- Suppession in Raw - - PowerPoint PPT Presentation
Intelligent Low-level Signal Detection and Zero- Suppession in Raw - - PowerPoint PPT Presentation
Intelligent Low-level Signal Detection and Zero- Suppession in Raw LArTPC Waveforms through Deep Learning Techniques Lorenzo Uboldi Supervisor Michael Wang Final report 24 September 2019 DUNE Deep Underground Neutrino Experiment is a LArTPC
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DUNE
Deep Underground Neutrino Experiment is a LArTPC detector that aims to study:
- Neutrinos from accelerator
- Rare events neutrinos (Supernovae burst, proton decay)
The latter have intrinsic problems:
- lower energy, close to the limit of the detector
- to have higher chances to be detected need 100% live time
Solutions:
- Save all data and analyse offline (throughput ~ TB/s)
- Online data discrimination
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For low energy events:
- Too much data from DAQ
- Signal and noise are almost indistinguishable
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- Zero suppression method
- Events with charge collection below a fixed threshold are
discarded
Classical approach
Very hard to detect low energy neutrinos (e.g.: from supernova burst)
Lorenzo Uboldi | Final report 24/09/19
Use machine learning. Benefits:
- We don’t have to study and develop a method to
discrimante signal
- The machine will learn itself what a signal is and what
is not
- Sometimes the machine is able to undestand
underlying features and correlations that we are not Cons:
- We need labelled data (Monte Carlo must be accurate)
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New approach
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What is a “classical” neural network?
y∈[0,1] X max(0,wi Xi)
Input vector to each neuron
1 1+e
−wi xi
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Advanced NN: Convolutional Neural Networks
- Convolutional NNs use convolution to take advantage of the
space invariance and to extract features from data.
- Neurons are replaced by filters that are fitted to find features
- Each layer is made of many filters
2-dimensional CNN is the cutting edge technology for image recognition, object detection, self- driving cars, ecc... Waveforms are one dimensional We use 1D Deep Convolutional Neural Network
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Learning process
Supervised learning is the process where labelled data is given to a neural network and its weights are fitted to give the most accurate predictions as possible Data 1 Labels Fit and adjust weights Predictions 0.02 0.36 0.94 The training process requires a lot of data to be sensitive. I used ~400000 waveforms for training.
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Unseen data
Trained Network Predictions For testing a model the labelled data is split:
- 80% for training;
- 20% for testing predictions performances
Inference
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Results for monoenergetic 5 MeV neutrinos
2 4 6 8
Epochs
0.75 0.80 0.85 0.90 0.95 1.00
Accuracy
Training accuracy Validation accuracy
Test set Accuracy U Plane 0.955 V Plane 0.976 Z Plane 0.974
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Simulated waveforms have a minimum of 2000 electrons productions: Lower than actual zero suppression threshold
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Fast, light and robust CNN has been developed
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1 2 3 4 5 MeV 0.0 0.5 1.0 1.5 2.0 2.5 3.0 A.U.
Energy deposited
Argon Krypton Radon CC
Next step: realistic dataset
- Data generated from
10,000 events
- Minimum collection of 2000
electrons
- Neutrinos from the
Supernova “marley” generator (Charge Current Neutrino)
- Radiological background is
a mixture of Radon 222, Argon 39 and Krypton 85
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Dataset
222Rn
14.3%
85Kr
14.3%
39Ar
14.3% CC 14.3% Noise 42.9% 778979 waveforms picked randomly from 10000 events:
- 80% used for training and
validation
- 20% for testing
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Strategy
- First neural network
- Second neural network
To discriminate any signal from noise To discriminate neutrinos from background Noise Neutrino Background Each NN has six convolutional layers developed to exploit the spatial invariance of the peak
Lorenzo Uboldi | Final report 24/09/19
False negative:
- Radiological = 95.6 %
- Neutrinos
= 0.4 %
Radio Neutrinos Predicted label Radio Neutrinos True label 0.998 0.002 0.058 0.942
Second NN
Noise Signal Predicted label Noise Signal True label 1.000 0.000 0.125 0.875
First NN
Results
False positive:
- Radon
= 26.1 %
- Argon
= 17.0 %
- Krypton = 56.8 %
At the end 92.21 % of the neutrinos are saved
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1 2 3 4 5 6 MeV 500 1000 1500 2000 2500 #
Energy deposited
Saved CC Lost CC Confused radio 1 2 3 4 5 6 MeV 100 101 102 103 # Saved CC Lost CC Confused radio
Results
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Peak finding, data preparation
15 15 15
1000 2000 3000 4000 25 20 15 10 5 5 10 15
20 40 60 80 100 6 4 2 2 4 20 40 60 80 100 6 4 2 2 4 6 20 40 60 80 100 6 4 2 2 4 6 20 40 60 80 100 25 20 15 10 5 5 10 15
440 windows large 100 bins, moving 10 bins at time Out = 0 Out = 0 Out = 0 Out = 0 Inside = 1
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Results
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1000 2000 3000 4000 10 5 5 10 ADC 1000 2000 3000 4000 5 5 ADC 100 200 300 400 0.0 0.2 0.4 0.6 0.8 1.0 Peak probability 100 200 300 400 0.0 0.1 0.2 0.3 0.4 0.5 0.6 Peak probability
Another CNN was trained on labelled “windows” data Accuracy of more than 99% Red line is the position of the peak given by the Monte Carlo
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Last step: ICARUS data
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1000 2000 3000 4000 10.0 7.5 5.0 2.5 0.0 2.5 5.0 7.5 ADC
ICARUS is a LArTPC detector part of SBN at Fermilab. It aims to study neutrino oscillations, sterile neutrino, ecc... Problem: due to “hot” electronic the noise is very high, in particular middle induction panel has a really poor signal-noise ratio
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Since ICARUS is a LArTPC detector as DUNE will be, why not to apply the developed method to it?
CNN method applied to ICARUS
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- Actual algorithm stores all waveforms and performs a heavy computing
de-convolution to extract signal from noise. Must run offline and needs huge storage space and a lot of time.
- Performance for events with less than 15000 collected electrons drops
below 75% of accuracy
- The CNN trained on ICARUS data keeps an accuracy between 99.2%
and 99.8% for events with collected electrons as low as 2000
- The NN for peak finding has an accuracy of 98%: the overall accuracy is
higher than 97%!
- The inference speed is so high that there is no need to make it offline:
a Nvidia Tesla K80 is actually faster than the detector throughput
Further Developement
For DUNE:
- Use a training set derived from a much bigger number of events in order to
generalize better and being able to avoid sensitivity on statistical fluctuations
- Improve accuracy
- Design a specific hardware (FPGA or ASIC) for our CNN able to handle a
huge throughput of data for live application (EdgeTPU by Google has been tested with no satisfying results) For ICARUS:
- Include our method in LarSoft and perform more accurate tests and
comparisons
- If it turns out to be robust and stable, include hardware and software in the
DAQ for the CNNs predictions
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