Fragment Mass Analyzer

Recoil Detection Efficiency of the FMA

You specify:
  • The projectile Zproj, Aproj, and target Ztar, Atar
  • The target thickness (mg/cm2)
  • The beam energy (MeV)
  • The number of protons, neutrons, and alphas evaporated by the compound nucleus
  • The average energy at which they are evaporated (MeV)
  • The distance from the target to the FMA (cm)
  • The diameter of the FMA aperture (cm)
  • The minimum and maximum charge states that the FMA will detect, Qmin and Qmax
The program will simulate 10,000 individual reactions and return:
  1. The half angle for the recoil.  (Half of the recoil nuclei are emitted with angles smaller than the half angle.) Half angles are calculated for:
    • only particle evaporation of the recoil
    • only angular straggling of the recoil in the target1
    • the combined effect of particle evaporation and angular straggling

  2. Full-width-half-maximum for:
    • Recoil energy distribution due only to energy straggling
    • Recoil energy distribution due only to particle evaporation
    • Recoil energy distribution due to energy straggling and particle evaporation combined

  3. Full-width-half-maximum for charge distribution.
         
  4. The efficiency of the FMA for the following:
    • Recoil angle (gives a percentage of the recoils with angles less than the maximum detectable angle) for:
      • particle evaporation
      • angular straggling in the target
      • final recoil angle due to both effects
    • energy acceptance of the FMA (±20% of the average recoil energy) for:
      • Only energy straggling
      • Only particle evaporation
      • Energy straggling and particle evaporation
    • charge state distribution (detects recoils between Qmin and Qmax)
    • total efficiency for all of the effects combined
References:
    1. J.S. Dionisio, et al., Nuclear Instruments and Methods in Physics Research A282 (1989) 10.
    2. V.S. Nikolaev & I.S.Dmetriev, Physics Letters.  A28 (1968) 277.
 

Fill in the items below and click Calculate 

Zproj  Aproj  Ztar  Atar 
Beam Energy (MeV) 
Target Thickness (mg/cm2 )
Qmin      Qmax 
Diameter (cm)      Distance (cm) 

Evaporated particles:
protons:    number      energy (MeV) 
neutrons:  number      energy (MeV) 
alphas:      number      energy (MeV)