Nuclear electronics

A.Y. 2020/2021
Overall hours
Learning objectives
The course aims to provide students with knowledge and understanding of the electronic noise and its propagation through time-invariant/time-variant linear circuits, as well as with the ability to optimize the signal-to-noise ratio in presence of non-white noises. The optimization of a high-resolution nuclear-radiation spectrometer will be studied in detail as a case study.
Expected learning outcomes
At the end of the course, students will be able to
1. Discuss the physical mechanisms related to electronic-noise generation
2. Describe the spectral power density of noise and calculate the signal-to-noise ratio
3. Propagate the electronic noise through linear circuits and calculate the input-referred noise density
4. Discuss the weight-function and optimal filtering-concepts
5. Describe in detail the functional blocks of an electronic chain for ionizing-radiation spectroscopy
6. Discuss the working principle and the properties of a charge-sensitive preamplifier
7. Derive the current signals seen at the electrodes of radiation detectors
8. Discuss the techniques for the optimization of a nuclear spectrometer at physical and processing level
Course syllabus and organization

Single session

Lesson period
Second semester
The course will be delivered entirely remotely in case of travel restrictions due to Covid-19. In this case, the lectures will be offered in virtual classrooms (zoom platform) in synchronous connection, with the possibility of real-time interaction between the students and the teacher.
Course syllabus
This course is focused on the the front-end electronics for semiconductor detectors, with a particular emphasis on the electronic noise, its physical origin, and the principal techniques to minimize its impact. The considered topics are:
- Fundamentals on Electronic Signal and Noise.
Description of signal and noise in the time and frequency domains. Principal sources of noise: thermal noises, shot noise, 1/f and Lorentzian noise. Autocorrelation function and power spectral density of noise. Signal-to-noise ratio, measurement resolution.
- Semiconductor Detectors of Ionizing Particles and Radiations (X and gamma).
Working principles. Fano factor. Important electrical parameters including datector capacitance and leakage current. Fringe effects. Peak-to-valley ratio.
- Signal Preamplification and Amplification.
Essentials of negative-feedback virtual-earth amplifiers. Charge amplifier: circuit structure, transfer function, transition time, decay time, dead time. Equivalent Noise Charge.
- Optimization of the Spectral Measurements.
Optimum matching of the detector-preamplifier system. Matched filter. Analog shaper amplifiers. Weight function, shaping time, baseline restorer.
- Analog-to-Digital Conversion of the Signal and Digital filtering.
Conversion techniques. Integral and differential nonlinearities. Correction techniques. Digital shaper amplifiers and digital baseline restorers.
Prerequisites for admission
Attendance of one introductory Electronics course or laboratory course is recommended .
Teaching methods
The didactic method includes both theoretical lessons in which the teacher shares knowledge and skills with students, and practical lessons in which the teacher shows students how the theory exposed is reflected in real physical systems. A "top-down" didactic approach is adopted. Starting from an overall description of the system, individual blocks will be studied in deeper and deeper detail.
Teaching Resources
Course notes, by Alberto Pullia
Assessment methods and Criteria
The exam consists of an interview of about thirty minutes. The understanding of the physical mechanisms underlying electronic noise as well as the knowledge and understanding of a topic of the program chosen by the teacher will be verified. The exam will evaluate both the skills acquired and the critical skills in the discussion of specific points, including new ones.
FIS/04 - NUCLEAR AND SUBNUCLEAR PHYSICS - University credits: 6
Lessons: 42 hours
Professor: Pullia Alberto
By appointment