Comprehensive Guide: How to Calculate Energy Loss in a Synchrotron

Summary

Calculating energy loss in a synchrotron requires a deep understanding of the underlying physics principles and the application of various mathematical formulas. This comprehensive guide will provide you with the necessary tools and techniques to accurately determine the energy loss in a synchrotron, covering key aspects such as energy loss per turn, power radiated, synchrotron radiation damping, longitudinal damping time, transverse plane damping, and measurement and simulation methods.

Energy Loss per Turn

how to calculate energy loss in a synchrotron

The energy loss per turn due to synchrotron radiation in a synchrotron is given by the formula:

$$U_0 = \frac{4 \pi r_0 e^2 c}{3 (m_0 c^2)^2} \cdot \frac{E^4}{\rho^2}$$

Where:
– $U_0$ is the energy lost per turn
– $r_0$ is the classical electron radius (2.818 × 10^-15 m)
– $e$ is the elementary charge (1.602 × 10^-19 C)
– $c$ is the speed of light (3 × 10^8 m/s)
– $m_0$ is the rest mass of the electron (9.109 × 10^-31 kg)
– $E$ is the energy of the electron
– $\rho$ is the radius of curvature of the synchrotron

To calculate the energy loss per turn, you need to know the values of the electron energy ($E$) and the radius of curvature ($\rho$) in the synchrotron.

Example:
Consider a synchrotron with the following parameters:
– Electron energy, $E = 10 \text{ GeV}$
– Radius of curvature, $\rho = 100 \text{ m}$

Substituting these values into the formula, we get:

$$U_0 = \frac{4 \pi (2.818 \times 10^{-15} \text{ m})(1.602 \times 10^{-19} \text{ C})(3 \times 10^8 \text{ m/s})}{3 (9.109 \times 10^{-31} \text{ kg} \times (3 \times 10^8 \text{ m/s})^2)^2} \cdot \frac{(10 \times 10^9 \text{ eV})^4}{(100 \text{ m})^2}$$

Simplifying the calculation, we get:

$$U_0 = 6.67 \text{ MeV}$$

This means that the energy lost per turn in this synchrotron is 6.67 MeV.

Power Radiated

The power radiated by a particle in a synchrotron is given by the formula:

$$P_0 = \frac{2 r_0 e^2 c}{3 (m_0 c^2)^2} \cdot \frac{E^4}{\rho^2}$$

Where:
– $P_0$ is the total power radiated by the particle
– $r_0$ is the classical electron radius (2.818 × 10^-15 m)
– $e$ is the elementary charge (1.602 × 10^-19 C)
– $c$ is the speed of light (3 × 10^8 m/s)
– $m_0$ is the rest mass of the electron (9.109 × 10^-31 kg)
– $E$ is the energy of the electron
– $\rho$ is the radius of curvature of the synchrotron

Using the same example values as before:
– Electron energy, $E = 10 \text{ GeV}$
– Radius of curvature, $\rho = 100 \text{ m}$

Substituting these values into the formula, we get:

$$P_0 = \frac{2 (2.818 \times 10^{-15} \text{ m})(1.602 \times 10^{-19} \text{ C})(3 \times 10^8 \text{ m/s})}{3 (9.109 \times 10^{-31} \text{ kg} \times (3 \times 10^8 \text{ m/s})^2)^2} \cdot \frac{(10 \times 10^9 \text{ eV})^4}{(100 \text{ m})^2}$$

Simplifying the calculation, we get:

$$P_0 = 8.85 \text{ MW}$$

This means that the total power radiated by the particle in this synchrotron is 8.85 MW.

Synchrotron Radiation Damping

The damping of energy fluctuations due to synchrotron radiation in a synchrotron is described by the equation:

$$\frac{dU}{dt} = -\frac{2 c r_e}{3 m_0 c^2} \cdot \frac{E^4}{\rho^2}$$

Where:
– $\frac{dU}{dt}$ is the rate of change of the particle’s energy over time
– $r_e$ is the classical electron radius (2.818 × 10^-15 m)
– $m_0$ is the rest mass of the electron (9.109 × 10^-31 kg)
– $c$ is the speed of light (3 × 10^8 m/s)
– $E$ is the energy of the electron
– $\rho$ is the radius of curvature of the synchrotron

Using the same example values as before:
– Electron energy, $E = 10 \text{ GeV}$
– Radius of curvature, $\rho = 100 \text{ m}$

Substituting these values into the formula, we get:

$$\frac{dU}{dt} = -\frac{2 (3 \times 10^8 \text{ m/s})(2.818 \times 10^{-15} \text{ m})}{3 (9.109 \times 10^{-31} \text{ kg} \times (3 \times 10^8 \text{ m/s})^2)} \cdot \frac{(10 \times 10^9 \text{ eV})^4}{(100 \text{ m})^2}$$

Simplifying the calculation, we get:

$$\frac{dU}{dt} = -1.67 \times 10^{12} \text{ eV/s}$$

This means that the rate of change of the particle’s energy due to synchrotron radiation damping is -1.67 × 10^12 eV/s.

Longitudinal Damping Time

The longitudinal damping time in a synchrotron is given by the formula:

$$\tau_s = \frac{2 T_0}{\sqrt{\frac{2 c r_e}{3 m_0 c^2} \cdot \frac{E^4}{\rho^2}}}$$

Where:
– $\tau_s$ is the longitudinal damping time
– $T_0$ is the revolution period of the synchrotron
– $r_e$ is the classical electron radius (2.818 × 10^-15 m)
– $m_0$ is the rest mass of the electron (9.109 × 10^-31 kg)
– $c$ is the speed of light (3 × 10^8 m/s)
– $E$ is the energy of the electron
– $\rho$ is the radius of curvature of the synchrotron

Using the same example values as before:
– Electron energy, $E = 10 \text{ GeV}$
– Radius of curvature, $\rho = 100 \text{ m}$
– Revolution period, $T_0 = 1 \text{ ms}$

Substituting these values into the formula, we get:

$$\tau_s = \frac{2 (1 \text{ ms})}{\sqrt{\frac{2 (3 \times 10^8 \text{ m/s})(2.818 \times 10^{-15} \text{ m})}{3 (9.109 \times 10^{-31} \text{ kg} \times (3 \times 10^8 \text{ m/s})^2)} \cdot \frac{(10 \times 10^9 \text{ eV})^4}{(100 \text{ m})^2}}}$$

Simplifying the calculation, we get:

$$\tau_s = 5.77 \text{ ms}$$

This means that the longitudinal damping time in this synchrotron is 5.77 ms.

Transverse Plane Damping

For the transverse plane in a synchrotron, the damping is given by the equation:

$$\frac{dU}{dt} = -\frac{2 c r_e}{3 m_0 c^2} \cdot \frac{E^4}{\rho^2} \cdot \frac{D}{\rho}$$

Where:
– $\frac{dU}{dt}$ is the rate of change of the particle’s energy over time
– $r_e$ is the classical electron radius (2.818 × 10^-15 m)
– $m_0$ is the rest mass of the electron (9.109 × 10^-31 kg)
– $c$ is the speed of light (3 × 10^8 m/s)
– $E$ is the energy of the electron
– $\rho$ is the radius of curvature of the synchrotron
– $D$ is a lattice parameter

Using the same example values as before:
– Electron energy, $E = 10 \text{ GeV}$
– Radius of curvature, $\rho = 100 \text{ m}$
– Lattice parameter, $D = 10 \text{ m}$

Substituting these values into the formula, we get:

$$\frac{dU}{dt} = -\frac{2 (3 \times 10^8 \text{ m/s})(2.818 \times 10^{-15} \text{ m})}{3 (9.109 \times 10^{-31} \text{ kg} \times (3 \times 10^8 \text{ m/s})^2)} \cdot \frac{(10 \times 10^9 \text{ eV})^4}{(100 \text{ m})^2} \cdot \frac{10 \text{ m}}{100 \text{ m}}$$

Simplifying the calculation, we get:

$$\frac{dU}{dt} = -1.67 \times 10^{11} \text{ eV/s}$$

This means that the rate of change of the particle’s energy due to transverse plane damping is -1.67 × 10^11 eV/s.

Measurement and Simulation

Energy loss in a synchrotron can be measured and simulated using coherent synchrotron radiation (CSR) as a function of beam current and energy. CSR is a powerful tool for understanding the impact of synchrotron radiation on the electron beam dynamics.

Measurements and simulations can provide valuable insights into the energy loss mechanisms and help optimize the performance of the synchrotron. By combining theoretical calculations with experimental data and simulations, researchers can develop a comprehensive understanding of energy loss in a synchrotron and implement strategies to mitigate its effects.

Conclusion

This comprehensive guide has provided you with the necessary formulas, examples, and technical details to calculate energy loss in a synchrotron. By understanding the underlying physics principles and applying the provided equations, you can accurately determine the energy loss per turn, power radiated, synchrotron radiation damping, longitudinal damping time, and transverse plane damping. Additionally, the importance of measurement and simulation techniques using coherent synchrotron radiation has been highlighted. With this knowledge, you can now confidently tackle energy loss calculations in synchrotrons and contribute to the advancement of particle accelerator technology.

References

  1. Synchrotron Radiation Lecture
  2. Measurement and Simulation of Coherent Synchrotron Radiation
  3. Measurement and Simulation of Coherent Synchrotron Radiation at Jefferson Laboratory
  4. Synchrotron Radiation Damping
  5. Synchrotron Radiation Basics