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How to Use the Data

The 8 TeV data for education is available on the CERN Open Data Portal. You can download the files directly from the portal, but we recommend remote data access.

For remote data access, you can use the CERN Open Data Client, leveraging the xrootd protocol. This will allow you to retrieve the necessary URLs and access the data directly from CERN’s storage systems.

Install the cernopendata-client package along with the fsspec-xrootd package by running:

pip install cernopendata-client fsspec-xrootd

Retrieving File URLs​

Once the client is installed, you can use it to obtain the URLs of the data files, for example, via their DOI (Digital Object Identifier). To get the file URLs from this record, you can use the following command:

cernopendata-client get-file-locations --doi 10.7483/OPENDATA.ATLAS.TC5G.AC24 --protocol xrootd

This command will return a file location like the following:

root://eospublic.cern.ch//eos/opendata/atlas/OutreachDatasets/2016-07-29/MC/mc_147770.Zee.root

Accessing Data​

Using the xrootd protocol, you can stream the data directly into your code without downloading the full dataset to your local machine. Here’s a Python example using ROOT to open a file:

import ROOT

file_url = "root://eospublic.cern.ch//eos/opendata/atlas/OutreachDatasets/2016-07-29/MC/mc_147770.Zee.root"
file = ROOT.TFile.Open(file_url)

This approach allows for efficient access to large datasets hosted remotely on CERN's servers.

ATLAS Digital Archive (deprecated)​

Retrieving File URLs​

The 8 TeV data can also be found in the ATLAS Open Digital Archive. Once inside the databes, if you wish to download the data, choose the .zip version of the dataset to obtain the URL of a specific dataset. For getting a specific file, simply right-click on your chosen dataset and select "Copy link.". For streaming multiple files, you can systematically construct the URL.

The base URL is https://atlas-opendata.web.cern.ch/Legacy8TeV, which hosts all the datasets. For example, if you want to access the Monte Carlo sample for the decay of the Z boson into two electrons, you go to the MC folder. The file corresponding to Zrightarrowrightarrowee is mc_147770.Zee.root. To stream this file, the full URL would be:

https://atlas-opendata.web.cern.ch/Legacy8TeV/MC/mc_147770.Zee.root

Accessing Data​

You can stream the data directly into your code without downloading the full dataset to your local machine. Here’s a Python example using ROOT to open a file:

import ROOT

file_url = "https://atlas-opendata.web.cern.ch/Legacy13TeV/MC/mc_301323.ZPrime500_tt.2lep.root"
file = ROOT.TFile.Open(file_url)

This approach allows for efficient access to large datasets hosted remotely on ATLAS's servers.

Use examples​

For examples on how to retrieve the data and use it for analysis check our 8 TeV tutorials.