USE OF THE P-GRAM CONSTRUCTION FOR THE CALCULATION OF CHOPPER BURST SHAPES
The method of the P-gram construction is used to calculate the burst shape for one or more chopper rotors; i.e., the number of neutrons transmitted at any given time. The effects of any collimating devices in the chopped beam are included in a conceptually simple manner. The utility of the P-gram construction is further enhanced if there is more than one collimator in the beam, since the event of transmission through all consists of transmission through each individually. The P-gram picture consists of several overlapping P-grams, each appropriate to one collimating element, and the overlapping areas are those in which the joint transmission probability is unity. Only the shape of the P-gram for neutrons which cross the rotor centerplane at time zero, at which time the slit centerline is parallel to the x axis, is considered. The shape will depend upon the physical configuration of the rotor, the neutron speed, and the rotor angular speed. The equations for the apparent slit boundaries as seen by a neutron crossing the rotor centerplane at time zero are derived. A definition and derivation of an expression of the burst shape function is presented. (H.G.G.)
- Research Organization:
- Michigan. Univ., Ann Arbor
- NSA Number:
- NSA-17-018547
- OSTI ID:
- 4732059
- Report Number(s):
- TID-18396
- Country of Publication:
- United States
- Language:
- English
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