Enge Split-Pole Magnetic Spectrograph

Enge Split-Pole Magnetic Spectrograph
The Enge split-pole spectrograph is a magnetic device originally designed by Harold Enge for Scanditronix Corporation. The description of the instrument can be found in Ref. [1].

The device was created primarily to study nuclear reactions with light-ion projectiles but was adapted at ORNL to study heavy ion reactions as well. It can be operated in two basic modes: high vacuum or gas-filled. The high vacuum mode is typically to study high resolution particle (mainly proton and alpha) spectroscopy of the kind discussed in Ref. [2] and the gas-filled mode is adequate to measure heavy ion reaction recoils (see Ref. [3]) for cases where the recoil products are distributed over many charge states. A computer program (FATRUMP developed by J. Ford, S. T. Thorton, and J. Gomez del Campo) is available in order to set the important parameters needed for a given reaction. The program predicts the magnetic field needed to focus the reaction products and the location of the focal plane for optimum resolution. The maximum magnetic field is 16 KG for a current of about 450 A. The focal plane length is about one meter corresponding to a maximum radius of curvature of 90 cm and to about 60 cm for a minimum. Inside the camera box (never used with photographic plates) there are several mechanisms that move a support from which the detector is hanged. This allows the placement of the focal plane at the predicted position given by the code FATRUMP.

Presently the focal plane is equipped with a position sensitive avalanche detector (xy position sensitive), followed by a total energy plastic scintillator. A description of this system is given in Ref. [3]. We have used all kinds of focal plane detectors ranging from position sensitive solid state detectors (PSD) to proportional counters of the Borkowski-Kopp type. These detectors still exist and can be used upon request.

References

[1] J. E. Spencer and H. A. Enge, Nucl. Instrum. Methods 49, 181 (1967).
[2] J. L. C. Ford, Jr. et al., Nucl. Phys. A226, 189 (1974).
[3] J.F. Liang et al., Nucl. Instrum. Methods A435, 393 (1999).

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This file last modified Monday January 08, 2007