# PHYSICS LABORATORY III

**Academic Year 2021/2022**- 3° Year

**Teaching Staff:**

**Paola LA ROCCA**

**Credit Value:**9

**Scientific field:**FIS/01 - Experimental physics

**Taught classes:**42 hours

**Laboratories:**45 hours

**Term / Semester:**One-year

## Learning Objectives

The learning objectives of the course are the following:

- Provide theoretical and practical knowledge of experimental techniques concerning the interaction of radiation with matter, particle detectors, signal processing, electronics as well as statistical methods for simulation and data analysis.
- Make the students able to perform measurements using appropriate instrumentation.
- Provide basic knowledge on laboratory instrumentation.
- Make the students able to design simple experimental setups.
- Make the students able to perform simple estimations and produce graphs to analyse experimental data.
- Provide basic knowledge on simulation techniques and Monte Carlo methd.
- Introduce students to the ROOT data analysis framework.
- Improve students' skills (writing and speaking), to describe the topic, the methods, the results, the analysis procedure and the interpretation of the experiments output.

With reference to "Dublin descriptors", this Course contributes to provide the following skills:

__Knowledge and understanding:__

- Ability in induction and deduction methods.
- Ability to schematize a real problem, defining the physical quantities (scalars and vectors) that are essential for obtaining results.
- Capability to setup and define a problem by using quantitative relations (algebraic, differential, integral) between physical variables and to solve it by means of analytical or numerical algorithms.
- Capability to design simple experimental setups or to use scientific instrumentation to perform thermo-mechanics and electromagnetic measurements.
- Capability to carry out statistical analyses of results.
- Capability to perform analysis sessions of experimental data from modern physics experiments.
- Capability to perform numerical simulations.

__Capability to apply the knowledge in order to:__

- Describe physical phenomena by a correct and quantitative application of scientific methodologies.
- Capability to develop theoretical models.
- Evaluate the performance of experiments in nuclear physics and carry out the analysis of experimental data.
- Perform numerical calculations and simulation procedures.

__Autonomy of judgment:__

- Reasoning skills.
- Capability to find the most appropriate methods for a critical evaluation and interpretation of experimental data.
- Capability to understand the prediction of a model or theory.
- Capability to evaluate the accuracy and importance of existing measurements.
- Capability to evaluate the goodness and limits in the comparison between experimental data and theoretical predictions.

__Communication skills:__

- Abilities in computer programming.
- Capability to appropriately communicate scientific topics and problems, discussing the motivations and main results.
- Capability to describe in a written report a scientific topic or problem, discussing the motivations and main results.

## Course Structure

- The course includes lessons and exercises during hall lectures, laboratory demonstrations and experiments in the lab by the students.
- During hall lectures the teacher presents the theoretical course contents needed for understanding experiments in the lab, together with a description of the experiments procedure and of the instrumentation used. Particular attention is given to the data analysis techniques and to the representation of the experimental results obtained during lab activities.
- During the course the students carry out exercises on the use of laboratory instrumentation and are introduced to the use of the data analysis framework ROOT.
- In the lab students carry out the experiments described during hall lectures.
- 6 CFU (each corresponding to 7 hours) are dedicated to hall lectures, for a total of 42 hours, the remaining 3 CFU (each corresponding to 15 hours) are dedicated to lab activities and exercises, for a total of 45 hours. The course (9 CFU) therefore includes a total of 87 hours of didactic activities.
- Should the circumstances require online or blended teaching, appropriate modifications to what is hereby stated may be introduced, in order to achieve the main objectives of the course.

## Detailed Course Content

**Part I**

**1. Techniques and laboratory instrumentation**

Sensors for the measurement of physical quantities - Analog and digital sensors - Data acquisition from sensors - Digital multimetere- Analog and digital oscilloscopes - Vacuum techniques - Elements for vacumm production and measurement - Measurement of radiations from Infrared to ultraviolet - Optical fibers - Spectrophotometers - Radioactive sources

**2. Radiation Detectors**

Interaction of charged particle with matter - Bethe-Block relation - Range - Straggling - Energy loss of electrons and positrons - Photon interaction - Photoelectric effect - Compton Effect - Pair production - Electromagnetic showers - Particle detectors - Measure of energy, momentum, position, mass and charge of particles - General properties of a detector: sensitivity, resolution, efficiency, dead time - Gas detectors - Ionization chambers - Geiger counters - Solid state detectors - Strip, drift and pixel detectors - Radiation damage - Scintillation detectors - Light yield - Photomultipliers - Light guides and WLS fibers - APD and SiPM.

**3. Elements of Electronics**

Pulse signals from detectors - Analog and digital signals - Propagation of signals - Coaxial cables - SIgnal Generators- Power supply - Electronics for Nuclear Physics - The NIM standard - Linear electronics: preamplifier, amplifier, shapers - Basic knowledge of logic electronics: OR, AND, NOT circuits - Analog-to-digital converters (ADC and QDC) - Discriminators - Coincidence circuits - Counters - Trigger systems - Data acquisition - Digital pulse processing

**4. Data analysis and simulation techniques**

Knowledge of elementary statistics - Central values and dispersion indexes - Experimental distributions - Gauss and Poisson distributions - Experimental errors - SIgnificance test - Data analysis techniques in nuclear physics experiments - Spectra analysis - Background subtraction - Non linear fits . Multiparametric analysis - The ROOT software - SImulation of physical processed - Monte Carlo methods the GEANT package for detector simulation

**Part II: Laboratory experiments**

- Exercises on the use of Arduino Board
- Exercises on the use of laboratory instrumentation (electronics,..)
- Exercises on the use of the ROOT software
- Laboratory experiments (listed below, randomly assigned to students for the prepartion of a written report to be discussed during the oral exam)

1) Measurements carried out by means of Arduino board

2) Photoelectric effect and the measurement of the Planck constant

3) Study of discrete and continuous light spectra with a digital spectrophotometer

4) Detection of electrons with a Geiger counter and study of the absorption coefficient

5) Study of the light absorption at different frequencies

6) Gamma spectrometry and absorption coefficient with scintillators

7) Alpha spectrometry and study of energy loss with silicon detectors

8) Measurement of the energy spectrum of a beta source

## Textbook Information

**For the items concerning the interaction of particle and radiation with matter, particle detectors and electronics see one of the following textbooks:**

1. William R. Leo, Techniques for Nuclear and Particle Physics Experiments, Springer-Verlag

2. Glenn F. Knoll, Radiation Detection and Measurement, John Wiley and Sons

3. Claude Leroy and Pier-Giorgio Rancoita, Principles of Radiation Interaction in Matter and Detection, World Scientific

4. C.Grupen, B.Schwartz, Particle Detectors, Cambridge

**For items concerning statistics and data analysis techniques:**

5. J.R.Taylor, Introduzione all’analisi degli errori, Zanichelli