Modeling quadrupole mass analyzers with OmniTrak

Linear quadrupoles are widely used for ion mass spectrometry. They can separate ions by the ratio of mass number to charge number (M/Z) without a magnetic field, leading to compact, light and inexpensive systems. An assembly consists of a source of low-energy ions that enter an extended electrostatic  quadrupole. The voltage applied to the lens has […]

GamBet shielding calculation walkthrough

In a previous article, I discussed the basis of the H*(10) standard for radiation safety. Here, I’ll continue by demonstrating techniques for shielding calculations. I’ll use a published simple benchmark calculation to compare the results to several other Monte Carlo codes and to illustrate some of the advantages of GamBet. For this, I am grateful to […]

H*(10) calculations with GamBet

I recently had an inquiry from a prospective customer. He had investigated several Monte Carlo options and was impressed with one package because the developer emphasized that the software could perform H*(10) calculations. In reality, every Monte Carlo X-ray code has this capability. The only requirement is that the user be aware of the definition. To […]

Variance reduction techniques in GamBet

The GamBet software suite calculates the interactions of energetic photons, electrons and positrons with matter. In a previous sequence of three articles (Monte Carlo methods versus moment equations: Part A, Part B and Part C), I discussed how Monte Carlo calculations approximate the behavior of large collections of particles. The essence of the Monte Carlo method […]

Magnetic saturation: educated guessing

In finite-element solutions at low magnetic fields, the properties of ferromagnetic materials are not critically important. The quantity used in the solutions is γ= 1/μr. In this case, both 1/800 and 1/8000 are close to zero compared to unity; therefore, the details of the μr(B) curve make little difference in the solution. On the other hand, […]