New corrector system for the Fermilab Booster
We present an ambitious ongoing project to build and install a new corrector system in the Fermilab 8 GeV booster. The system consists of 48 corrector packages, each containing horizontal and vertical dipoles, normal and skew quadrupoles, and normal and skew sextupoles. Space limitations in the machine have motivated a unique design, which utilizes custom wound coils around a 12 pole laminated core. Each of the 288 discrete multipole elements in the system will have a dedicated power supply, the output current of which is controlled by an individual programmable ramp. This paper describes the physics considerations which drove the design, as well as issues in the control of the system.
Magnets and Magnetic Field Effects
The magnets of the circular accelerators that comprise the Fermilab complex have contributed to, responded to, and solved a string of accelerator physics issues. Most importantly, the magnets are supposed to generate high quality magnetic fields needed for stable long-term dynamics of the particles circulating in the rings. The quality of the transverse magnetic field B is given by the multipole coefficients in the expansion: 
 
$$ {B}_x+i\cdot {B}_y={B}_0{\displaystyle \sum_{n=0}\left({b}_n+i{a}_n\right){\left[\frac{x+ iy}{R_0}\right]}^n}, $$ 
 
(3.1) 
 
where R 0 is the reference radius (1 in. in the Fermilab accelerators), the pole number is 2(n + 1) and b n (a n ) are the normal (skew) multipole coefficients, and b 0 is unity. For example, the multipoles allowed by dipole symmetry, b 2, b 4, b 6, … are designed to be small and would be 0 for a pure cos θ coil winding. The precise coil placement, and hence good magnetic field uniformity at the relative level of the multipole coefficients of few 10−4, had the biggest effect on the accelerator performance.
Growth and Characterization of β-RDX Single-Crystal Particles
1,3,5-Trinitrohexahydro-s-triazine (RDX) single-crystal particles crystallized in the β phase have been successfully grown by sublimation–recrystallization. Synchrotron X-ray diffraction results confirm that the recrystallized products are β-RDX single crystals. Compared to the traditional solution deposition methods, the sublimation method used in this work breaks through the mass limitations during the growth of β-RDX. The distribution of α- and β-RDX on different substrates reveals that hydrophilic substrates are prone to grow β-RDX single crystals and that hydrophobic substrates prefer α-RDX single crystals. The sublimation rate dominates the growth of pure β-RDX. The mechanisms of the phase transition from β-RDX to α-RDX during the process of sublimation–recrystallization have been studied. The current results can promote the potential application of β-RDX in the propellant, explosives, and military fields.