87976 - Laboratory of Nuclear and Subnuclear Physics 2

Learning outcomes

At the end of the course the student will have a good knowledge of the detectors concepts to study events produced with colliders or fixed target experiments and will be familiar with the main techniques to identify particle charge and mass. Moreover, practice in the laboratory will allow the student to become familiar with some basic detectors, electronic instrumentation, DAQ system, data analysis and writing a report on the experimental work performed in the laboratory sessions.

Course contents

Fist module - classroom lectures

Cherenkov detectors

Cherenkov radiation: mechanism and features. Threshold effect and Cherenkov threshold counters. Radiator choice. Differential counters. Ring Imaging Cherenkov counters (RICH).Focusing techniques. Examples of application of Cherenkov detectors to several present and past experiments (Alice, Delphi, Babar, LHCb). Air Cherenkov detectors examples.

Transition Radiation Detectors

- Production of Transition Radiation. Spectrum, other features and consequences. Dependence of TR emission and detection on particle gamma, radiator features, detector features. Usefulness of TR for PID. Selected TR detector examples: AMS-02, Alice, Atlas.

Calorimeters

- Introduction. Main classification of calorimeters; principles of energy measurement; requirements.

- Electromagnetic showers. Recap of electron and photon energy loss in matter. Electromagnetic (EM) showers development and features: radiation length and Moliere radius. Longitudinal and transverse development of EM showers. Direction of shower particles and consequences.

- Electromagnetic calorimeters. Parametrization of calorimeter resolution. Homogeneous EM calorimeters: materials and implementation examples. Sampling EM calorimeters: features, technologies, implementation examples. Preshower detectors.

- Hadronic showers: generalities, nuclear interaction length, longitudinal and transverse development. EM component: physics mechanism, energy estimate and parametrisation. Content of the non-em component and consequences. Lateral and longitudinal profiles of hadronic showers. Hadronic shower profile in Cherenkov calorimeters. Shower containment.

- Calorimeter response: definition and meaning. Response in homogeneous calorimeters: electrons, muons, hadrons. e/h vs e/pi. Compensation. Measuring e/h indirectly. Sampling calorimeters: definition of sampling fraction in terms of mip energy loss. Response of a sampling calorimeter to electrons and photons. Spatial dependence of em response. Response to hadrons: low energy vs high energy. Response to individual non-em components. Response to neutrons. Neutron sampling fraction in hydrogen-enriched materials. History of compensation attempts. Summary of calorimeter compensation techniques.

- Fluctuations in calorimetry: impact on energy resolution. Sampling fluctuations and stochastic term of resolution. Fluctuations in hadronic showers, invisible energy fluctuations, impact on compensating vs non-compensating calorimeters. Electronics noise and other instrumental effects. Sampling fraction fluctuations. Summary and consequences for calorimeter design.

- Calorimeter calibration. Definitions and tools. Example for homogeneous calorimeters. Calibrating longitudinally segmented calorimeters: issues of section intercalibration with showers. Other effects.

- Future calorimeter projects. Motivations, future accelerator and detector projects. High granularity calorimeters: CALICE developments and the CMS HGCAL for HL-LHC. Dual readout calorimeters: theory, DREAM and RD52 developments, the dual readout calorimeter for the IDEA detector proposal for FCC.

 

Second module - classroom lectures

Detectors for very weakly interacting particles (neutrinos and dark matter candidates)

- General introduction on neutrinos: history, natural and artificial sources, interaction model, cross-sections, first detection with the Cowan-Reines experiment.

- Detection of solar neutrinos: radiochemical experiments, Natural and Heavy Water Cherenkov detectors (SK and SNO), Ultra-pure Liquid Scintillator detectors (Borexino). The solar neutrino problem, and its solution via neutrino oscillation.

- Detection of neutrinos from reactors: Kamland and its confirmation of Solar neutrino oscillation. Chooz experiment: Gd-loaded liquid scintillator

- Detection of atmospheric neutrinos: generalities (production, flavour composition, energy, interaction), Water Cherenkov detectors (SK): discrimination of nu_e from nu_mu, pattern of events: Fully and Partially Contained, Upward through-going and stopping muons. The atmospheric neutrino problem, and its solution via neutrino oscillation.

- Neutrino production at accelerators: ingredients for a neutrino beam, their detection (nu_tau with OPERA, nu_mu with MINOS).

- Detection of WIMPs: generalities on Dark Matter Direct detection, characteristics of the WIMP signal and the main background sources, main kind of detectors (scintillating crystals, bolometer, liquid noble time projection chambers), focus on the Liquid Xenon Double-Phase TPC and its ancillary systems (Neutron Veto, Muon Veto)

Third module - Laboratory activity

The baseline goal of the laboratory work is the measurement of the muon lifetime. Additional outcomes are the measurement of the negative muon capture rate in a material, or the cosmic muon charge ratio. The activity includes setting up the apparatus, data acquisition and analysis. A written report about the measurement will be required. In-class introductory lectures will prepare the students to the laboratory activity, which will be supervised by the professor and tutors and will work in small groups (3-4 students per group). The laboratory activity will require at least three visits to the laboratory, for a total of 10-12 hours depending on the yearly schedule and on the overall number of students. 

Readings/Bibliography

Material will be available on virtuale.unibo.it.

The textbooks dealing with the material of the course are

- W.R. Leo, Techniques for Nuclear and Particle Physics Experiments, Springer

- K. Kleinknecht, Detectors for Particle Radiation, Cambridge UP

- G.F. Knoll, Radiation Detection and Measurement, J. Wiley & Sons

- R. Wingmans, Calorimetry, Oxford Science Publications

 

Teaching methods

In-class lectures and exercises. Depending on the year, seminars by experts on specific topics could be offered in addition to normal lectures. Laboratory activity and the writing of the final report will happen in small groups. Group decision making and teamwork will be fostered.

IMPORTANT: in order to attend laboratory sessione, the safety course "MODULO 3" is required in addition to "MODULO 1" and "MODULO 2". Please find more information here

Assessment methods

Oral examination. The examination will consist of two parts:

1) interview to evaluate student's knowledge and understanding about the physics principles and techniques of the particle detectors described in the lectures of first module. In addition, a quick discussion dedicated to the laboratory experience and the group's report (third module) will be included.

2) interview to evaluate student's knowledge and understanding about the physics principles and techniques of the particle detectors described in the lectures of the second module.

The final score will be weighted between the outcome of the interviews about the modules 1-2-3 with weights approximately 50%-20%-30%.

 

Teaching tools

Slides, blackboard, hands-on laboratory activities.

Office hours

See the website of Luigi Guiducci

See the website of Marco Selvi

See the website of