-- KathrynGrimm - 2022-07-20

This page collects information useful for California State University students interning at CERN

Generally useful links:

Map of buildings and rooms at CERN: https://maps.web.cern.ch/?xmin=2488501.32&ymin=1119288.73&xmax=2498483.54&ymax=1126163.68&basemap=plan&mode=2D

Find something online from CERN: https://search.cern.ch/Pages/default.aspx or https://cern.service-now.com/service-portal

Glossary of terms for ATLAS: https://twiki.cern.ch/twiki/pub/Main/AtlasGlossaryAndATLASAcronymList/AtlasGlossary.pdf

Resources you have access to with your account: https://resources.web.cern.ch/resources/Manage/ListServices.aspx

Safety trainings: https://lms.cern.ch/ekp/servlet/ekp/TABLISTSESSIONS?DECORATEPAGE=Y

Requesting access to buildings and rooms: https://apex-sso.cern.ch/pls/htmldb_edmsdb/f?p=ADAMS3

LHC status: https://op-webtools.web.cern.ch/vistar/vistars.php?usr=LHC1

Craigslist for CERN: https://marketplace.web.cern.ch/

Reserving a desk: https://burotel.cern.ch/rooms/book (You can also go to the ATLAS Secretariat (40/4-D01) and ask them about it)

Joining e-groups: https://e-groups.cern.ch/e-groups/EgroupsSearchForm.do This is an extremely resourceful link when it comes to being put on the mailing list for specific groups. This provides access to join mailing lists for specific groups, whether it be in analysis, experimental, clubs, etc... If you find that your mentor recommends you to attend certain weekly meetings that are sent via email or join a mailing list for a channel to stay up to date on any new updates, this is the place to go to do so.

CERN box: https://cernbox.cern.ch Imagine cern box a google drive connected to your lxplus. Or really anyones lxplus. You can share or simply access files and data on your lxplus directory via a weblink. You can download files from the webpage, making it accesible using the internet. Therefore if you want to download something from your lxplus directory directly onto your local machine, cern box is great for that. Additionally, you can also send files via cernbox as well. Rather then sending a 3 GB data file via download and running into issues, you can send it to your mentor or colleague as a cernbox link for them to access and download as needed.

Code and software information:

Example code below.

ROOT Reference Guide: https://root.cern.ch/doc/master/classTLorentzVector.html , https://root.cern/doc/master/classTHistPainter.html#HP01a This is the guide to dealing with data within a root file. This reference guide provides syntax and information in accessing all things within a root file you may need at CERN. This includes documentation on the libraries that create a 1D histogram, or the correct way to change the color for a histogram distribution, as well as the various colors accessible to you in making your distributions. If you are coding in C++ or python and need to recall or look up how to call the transverse momentum or manipulate a TLorentzVector, etc..., this is extremely important for helping you navigating such things. Be sure to not just look at a given syntax and copy paste. It is best to press the link on the given syntax and review the function. Check the parameters that are required to be passed in, and what occurs within the function. Just because it simply states it outputs a specified variable, does not mean that it is the variable you want, it may have been computing different from what work you are doing. So when dealing with coding for root, and your results aren't as expected, read the documentation on what you are using.

Accessing your lxplus via Visual Studio Code: * lxplus_via_VSC.docx: This is quick step by step tutorial on how to set up lxplus remote connections via Visual Studio Code on your local machine, such as your personal laptop.

Latex, making publishable format pdfs with multiple histograms: * LaTex,_for_quick_formatting.docx: This is quick and easy tutorial on making a Latex file to create a pdf with multiple histograms posted side by side and scaled down for ease of review and analysis.

C++, creating histograms and accessing TTrees: https://indico.cern.ch/event/704163/contributions/2936719/ This is a link to a root tutorial in both C++ and python. It is highly recommend you do this tutorial in order to understand how to work with TTree's and creating histograms. In order to do the tutorial, downloaded the associated files for your method of computation. For C++ this means, download all files that. have a '.cpp' at the end of the file name as well as the 'Tutorial-ROOT.pdf'. These are the designated files and tutorial steps for C++.

  • ROOTtutorial-Takeaways.docx: This is a compilation of some quick takeaways from the root tutorial I thought where important to take note of, this is for C++ but may be applicable to its python counterpart.

Shell scripts, make the computer do all the work: Shells scripts are very simple, but highly desirable when it comes to having to run and input multiple command inputs into your terminal tom complete a task. To create a shell script, start by making a '.sh' file with whatever name you desire. What you input in your shell script file, is everything you input in your terminal, line by line. Wether it be changing the directory pathway or running code, whatever you put in the terminal, copy and paste it in the shell script in the order you desire. Save the shell script file, and run it and set back and relax. To run it, you want to use 'source'. Therefore you will want to input the following command into your terminal: source (script file name).sh . So rather then, inputing 20 command lines to complete a task, you simply type one.

Athena, generating ntuples: https://gitlab.cern.ch/atlas/athena This is a gitlab resource that provides documentation on athena resources, such as MadGraph and such. Therefore if you are generating ntuples and are having trouble with certain portions of your code, this is a great resource to review the library and see if your improperly implementing certain functions, or if you are miss providing certain parameters, etc.

The python script ratios.py ratios.py.txt reads in histograms from a root file and takes their ratios. Note that the file must be renamed to remove the .txt ending.

Python script MCplots.py: MCPlots.py.txt Reads information from a .root file with both real and MC data, fills histograms, and plots both weighted MC comparison plots and ratio plots. This can be run on lxplus or your local machine (depending on where the file is), and will need to be edited based on how many variables you want to make plots for as well as their specific histogram settings. In order to run on lxplus, you need to open a graphic session using either ssh -Y username@lxplusNOSPAMPLEASE.cern.ch or ssh -X username@lxplusNOSPAMPLEASE.cern.ch.

Setting Up PyROOT Tutorial If you have trouble setting up PyROOT I would recommend following this tutorial https://iscinumpy.gitlab.io/post/root-conda/

Useful Root & PyROOT Tutorial Here is a link to a PyROOT tutorial that I found useful https://indico.cern.ch/event/704163/contributions/2936719/. This tutorial should help with learning how to read root files and produce histograms.

Swan ~ Something that you might find useful is Swan. Swan is basically jupyter notebook for root. Here is the link for Swan https://swan.web.cern.ch/swan/

Space on lxplus: Every user has an area with ~infinite space on each lxplus machine in the directory /tmp/username/ (for example /tmp/kgrimm). BUT this area is deleted on a regular basis so it is only for temporary storage. If you exit lxplus and want to access the same directory again you need to specifically log back on to the same lxplus machine. For example if I store something on lxplus763:/tmp/kgrimm/ and then exit, I can go back to that area by ssh'ing directly to the machine: ssh kgrimm@lxplus763NOSPAMPLEASE.cern.ch -XY

Bash (terminal / command-line) resources:



Command for moving files from lxplus onto your local machine:

scp username@lxplusNOSPAMPLEASE.cern.ch:filepath/filename .

To move entire folders from lxplus, add the recursive "-r" flag:

scp -r username@lxplusNOSPAMPLEASE.cern.ch:folderpath/foldername .

The period at the end of the command moves the file/folder into the current location on your local machine. You can replace the period with a path if you want the file/folder in a different location on your machine.

Python script table.py: table.py.txt Reads information from one or more .txt files, puts the information into a table, and fills the cells with colors based on the data. This can be run either on lxplus or on your local machine, and will need to be edited based on how large you want your table to be and what information you want to include. In order to run on lxplus, you need to open a graphic session using either ssh -Y username@lxplusNOSPAMPLEASE.cern.ch or ssh -X username@lxplusNOSPAMPLEASE.cern.ch.

Getting around CERN and region:

Public transportation: Busses and Trams: https://www.tpg.ch/ Trains: https://www.sbb.ch/en & https://www.tgv-lyria.com/ch/en There are 74 different railway companies in CH, so this is just to get started.

To get around Genève (Zone 10) effectively you're going to want a SwissPass: https://www.swisspass.ch/home?lang=en To obtain one you're going to have to take the 18 from CERN to Gare Cornavin's TPG office and pay 45CHF per month, max 3 months. Expect the shipping address to be an issue if you're living in the CERN Hostel: they cannot ship there. The manager once allowed it to be shipped to their office "Agence TPG Lancy-Pont-Rouge" but another manager wouldn't allow that so we had to ship it to a friend's place in Fr. Apparently if you have an official desk at CERN you could get it shipped there, but details of that process aren't known.

Urban Connect ~ There are bikes, e-bikes, and e-scooters that you can use to get around onsite. In order to access these you will need to download the app Urban Connect. Once you download urban connect you need to register it to your CERN email. After you have set up everything you can check out the bikes and scooters from certain locations on site using the app. The bikes and scooters should not be taken off-site. Here is a link that goes into detail about this https://home.cern/news/announcement/cern/electric-scooters-and-bicycles-available-cerns-mobility-centre

Car Sharing Service ~

Food recommendations:


Obrasseur ~ one stop away from CERN on the 68 bus, just inside of St. Genis. Great for cheap beer and bites. https://www.obrasseur.com/

Charly's ~ the namesake for the C side of the ATLAS detector, it's a few more stops away on the 68 (don't listen to maps, get off at Jean Monnet so the walk is just 300m DOWNhill). They have decent cocktails, beer, and wine selection at reasonable prices. https://www.tripadvisor.com/Restaurant_Review-g675074-d7159769-Reviews-CHARLY_S_PUB-Saint_Genis_Pouilly_Ain_Auvergne_Rhone_Alpes.html They also have food, but Happy Grill is a Kebab place tucked behind with cheap meals. https://www.eat-list.fr/saint-genis-pouilly-01630/viandes-et-grillades-37/happy-grill-186916

Pub des Vergers ~ one real stop away from CERN on the 18 tram at Hôpital de la tours. They offer a variety of beer and liquor options with worldly food offerings, but this is the most expensive of the local watering holes because it's in Meyrin – expect to pay Swiss prices. Be warned that the snack items come in small portions. http://www.pubdesvergers.ch/index.html

Close restaurants with more flavor than R1 & R2

Luigia Academy ~ about 650m from Gate C (Rte Maxwell) It's an Italian cooking school by day, the best local Italian food by night. They have a well-stocked bar and large menu that's sure to have something you'll love. Save some room for dessert. They grow and pollinate their own ingredients in the garden with the hives, behind the restaurant. It may seem pricey, but you certainly get the quality you pay for. https://menu.luigia.ch/menu/luigia/fr

Don Pedro 1951 ~ about 800m from Gate C (Rte Maxwell) It's a bit hard to categorize, it's something like a French fusion place as they have expensive steaks, escargot, fondue, and truffle pasta to die for, but they also have less expensive options like burgers and salads. Still definitely have to pay Swiss prices, but it's not insane for the flavors you get. http://www.donpedro1951.ch/

Nirvana ~ as close as a restaurant can get to CERN without being on the property, it's a quick walk from A gate. It's a fancy Indian place with delicious food, highly variable service quality, and small portions for Swiss prices. It's definitely the worst option on this list for getting full of good flavor on a budget, but the food is quite good, even if it comes in petite portions. https://www.nirvana-geneve.ch/#

On Site Opportunities and Activities:

Summer Student Lecture ~ During the summer there will be many summer student lectures that you should check out if interested. In 2022 these lectures ran from through the month of July. There were 3 lectures a day that started at 9:15am and went until 12:35pm. These lectures covered a variety of topics ranging from cosmology to statistics to detectors. Here is the link to the a list of the lectures given in a 2022 https://summerstudent.web.cern.ch/lectures-2022

Summer Student Workshops ~ In addition to the summer student lectures there are summer student workshops offered in the summer. The workshops that I participated in were the ROOT analysis workshop and the cloud chamber workshop. I would recommend checking out a couple of these workshops if you can. The spots fill up fast for the workshops so if you’re interested make sure to sign up fast. This link should have a list of all the workshops that were in the summer of 2022 https://indico.cern.ch/category/6274/

Clubs ~ There are many clubs at CERN. One club that I participated in was the games club. The games club met every Sunday in restaurant 1 at 2:00pm to play board games. If you have an interest in boards and want to meet new people at CERN I would recommend checking out this club. Here is a link to the list of clubs at CERN https://indico.cern.ch/category/426/ which includes clubs for everything from cars to playing jazz music.

Shifts ~ Interns and Summer Students are not expected to take shifts, but Interns are generally allowed as long as they complete the required shift and desk trainings. They can be boring for some, but it's a nice way to hang out in AC for 8 hours and learn all about the details of the detector operations: https://atlasop.cern.ch/twiki/bin/view/Main/ShiftTraining

Topic attachments
I Attachment History Action Size Date Who Comment
Texttxt ComputeEffAlg.cxx.txt r1 manage 6.7 K 2022-07-27 - 12:48 AidanLaneMorson This is a C++ script that is used to do an efficiency analysis on triggers which is a part of their overall analysis. This file gets executed by running a python job options file with athena. This file outputs a bunch of TH1F objects for all of the different triggers that are fed to it with the python job options file. The histograms it produces are a plot of the pt of the leading jet for the tigger and a plot of the dijet mass.
Unknown file formatdocx LaTex,_for_quick_formatting.docx r1 manage 2185.5 K 2022-08-01 - 19:37 ThomasAdams This is quick and easy tutorial on making a Latex file to create a pdf with multiple histograms posted side by side and scaled down for ease of review and analysis.
Texttxt MCPlots.py.txt r1 manage 3.9 K 2022-08-02 - 11:33 AnnaKatelynGagnebin Python script to read information from a root file and create MC comparison and ratio plots.
Unknown file formatipynb Master_Notebook.ipynb r1 manage 86.1 K 2022-07-21 - 15:13 RebeccaRosaRobles This has all the scripts that were used (or attempted to be used) for my project. It includes plotting histograms for a set of ntuples, saving those plots both as .root files and as pdfs, ratio plots, and on superimposing histograms for one composite graph. Each kernel is specified with a markdown cell above it describing what it should do
Unknown file formatdocx ROOTtutorial-Takeaways.docx r1 manage 36.3 K 2022-07-29 - 21:20 ThomasAdams This is a compilation of some quick takeaways from the root tutorial I thought where impotant to take note of.
Texttxt hist_macro_combined.py.txt r1 manage 11.7 K 2022-07-27 - 14:45 ArmanHamidMoradi The Purpose of this code is to produce histograms from both data and MC root files, and superimpose the created histograms onto each other. This code can work in two ways. The first way is by putting in system arguments for the files that you want to produce the histograms for.The order of the system arguments matters. Put all the data files first and then put the MC simulation files after.The files need to be ordered the same way in order to superimpose them correctly. For example the first data file is paired with the first MC file, the second data with the second MC etc. The second way that the code works is by going through every file in two different directories given in the code. It produces the histograms for these files and then superimposes them onto each other.
Texttxt hist_overlay.py.txt r1 manage 2.0 K 2022-07-21 - 17:32 AidanLaneMorson This is a PyRoot macro that takes a root file as input. The root file must contain TH1F histograms. It then takes these histograms and creates a pdf file with them overlaid.
Unknown file formatdocx lxplus_via_VSC.docx r1 manage 1834.6 K 2022-07-29 - 20:48 ThomasAdams This is quick step by step tutorial on how to set up lxplus remote connections via Visual Studio Code on your local machine, such as your personal laptop.
Texttxt mjj_plot.py.txt r1 manage 4.9 K 2022-07-21 - 17:43 AidanLaneMorson This is one of the plotting scripts I used for my project, it is similar to the hist_overlay file I attached but contains lines for creating efficiency curves. This plots information for triggers that trigger on dijet mass "mjj". This script still creates a overlay of the histograms but then takes the histograms and makes a TEfficiency plot which is just a ratio plot but much similar when using ROOTs TEfficiency class.
Texttxt ratios.py.txt r1 manage 0.5 K 2022-07-21 - 07:48 KathrynGrimm Python script to read in histograms from a root file and take their ratios
Texttxt table.py.txt r1 manage 3.7 K 2022-07-26 - 14:25 AnnaKatelynGagnebin Python script to read information from one or more files and create a table with color.
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Topic revision: r17 - 2022-09-06 - FrankBernardGrijalvaIii
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