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In this lab the students will measure some fundamental properties of cosmic rays, as detected by a large size Charge-Coupled Device (CCD). Cosmic rays passing through the detector leave a trail of ionizations which are “visualized” by the CCD with very fine resolution. The students will first familiarize themselves with the basic processes of particle-matter interactions by searching for a variety of “tracks” seen in the CCD.  They will then devise a clustering algorithm to reconstruct the tracks and determine the physical properties of the incident cosmic ray – its direction of arrival and the energy deposited in the detector. The ultimate goal of the lab is the measurement of the absolute flux of cosmic rays – the number of particles arriving /cm2/s/sr – and its angular dependence, which we may compare with the literature.

* 1Cosmic Rays in a CCD
* 2Literature
* 3Software
* 4Python scripts
* 5CCD Data
* 6Advice for report

Cosmic Rays in a CCD

Introduction to the lab: Slides

{FIXME ${/download/attachments/263128974/CCDPhoto.jpg?version=1&modificationDate=1610256388000&api=v2}$            {FIXME ${/download/attachments/263128974/CCDChamber.jpg?version=1&modificationDate=1610256491000&api=v2}$                         {FIXME ${/download/attachments/263128974/CCDtracks.png?version=1&modificationDate=1610373218000&api=v2}$          Figure 1. The CCD used for this lab                                   Figure 2: The CCD chamber                   Figure 3. A portion of a CCD image showing particle tracks

Literature

  • Cosmic Rays
           Notes with definitions and relevant calculations for the cosmic ray flux
           The Particle Data Group section on Cosmic Rays (30.1, 30.2. and 30.3)
  •  Energy loss of charged particles in materials (dE/dX)
            Slides (from Katrina Muller, UZH; in particular: dE/dX Bohr classical derivation slides 5-9, Bragg curve slides 24-25, dE/dX fluctuations slides 28-30)  
             The Particle Data Group section on Passage of Particles Through Matter (34.2) 
  • Charge Coupled Devices (CCDs) 
More Than You Ever Really Wanted to Know About Charge-Coupled Devices   (the first three pages)
             Particle tracks in a CCD   (a measurement of the DAMIC experiment; the data for this lab were taken with one of their CCDs)

Software

The following software is required for this lab. If you have already installed anaconda you may have already most of it.

  • SAOImageds9, an image visualization tool for astronomical data. You will use ds9 to visualize and familiarize with the CCD images. The tool you will mostly use is activated by “Edit” → “Region” and then “Region”→”Shape”→“Box”. If you double click on a region of interest in the image, a box will appear. Select “Analysis”→”Statistics” to display relevant statistical information on the pixels contained in the box, and “Analysis”→”Histogram” to produce an histogram of the values of the pixels in the box.
  • python3
  • astropy
  • python modules: pickle, scipy, pyplot

Python scripts

All the files required for the lab are contained here :
  • ccdlab211_recon.ipynb                    Read a CCD image and produce a cluster file
  • ccdlab211_eventdisplay.ipynb         Display clusters
  • ccdlab211_analyse.ipynb                  Analyse the cluster file
  • ccdlab211_lib_functions.py               Library with functions to read the CCD image
  • ccdlab211_lib_plots.py                       Library with functions to make plots
  • ccdimagelab211_1.fits                        one CCD image so that you can start working

You will use jupyter notebook to develop your program

CCD Data

The raw data for this lab consist of images taken with a CCD of physical dimensions 6176 pixels x 1032 pixels. Each pixel is 15 μm x 15 μm. For each image, the CCD was exposed to cosmic rays for 16.5 min. 

The CCD data sample (100 images, approx 1.5 Gb) can be downloaded here

Advice for report

  • TBD