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 UNITED STATES ATOMIC ENERGY COMMISSION 
 
 184-INCH CYCLOTRON VERTICAL BEAM OSCILLATIONS 
 IN THE REGION OF 82-INCH RADIUS 
 
 by 
 
 James Vale 
 
 University of California 
 
 This document consists of 7 + 1 pages 
 
 Date of Manuscript: February 26, 1947 
 Date Declassified: May 23, 1947 
 
 Its issuance does not constitute authority 
 
 to declassify copies or versions of the 
 
 same or similar content and title 
 
 and by the same suthor(s). 
 
 UNIV, OF FLUB 
 onr.i, iMF^NTS DEPT 
 
 Technical Information Division, Oak Ridge Directed Operations- 
 AEC, Oak Ridge, Tenn., 10-22-48—1000-11980 
 
 Printed in U.S.A. 
 PRICE 10 CENTS 
 
 DEPOSITORY 
 
 J 
 
Digitized by the Internet Arclnive 
 
 in 2011 witln funding from 
 
 University of Florida, George A. Smathers Libraries with support from LYRASIS and the Sloan Foundation 
 
 http://www.archive.org/details/184inchcyclotron00univ 
 
184-INCH CYCLOTRON VERTICAL BEAM OSCILLATIONS 
 IN THE REGION OF 82 -INCH RADIUS 
 
 By James Vale 
 Experiment done by: L. Houser, R. Watt, and J. Vale 
 
 INTRODUCTION 
 
 It was discovered early in the operation of the 184-inch cyclotron, that the beam did not go out 
 to the expected 85 -inch radius. 
 
 The Theoretical Group suggested that the beam did not go beyond a radius of 82 inches because 
 of vertical oscillations building up in the vicinity of this point. According to their calculations, the 
 vertical oscillations built up a large enough amplitude at the point where n = 0.2 (n = - R/H dH/dR) 
 so that the beam hit the dee and was lost. An attempt had been made to find this vertical spreading, 
 previously, but it was unsuccessful. Consequently, the following experiment was performed. 
 
 EXPERIMENTAL SETUP 
 
 Several targets were made of l/l6-inch copper sheet. These were U-shaped and were placed in 
 the tank and bombarded. The plane of the sheet was vertical, and the arms of the U were roughly par- 
 allel to the dee face. See sketch of target appended hereto. 
 
 Thus, the beam had to traverse the slot in the U to reach the back of the target. Hence, any 
 vertical spreading in the beam would result in its hitting the U arms. 
 
 These targets were run into the tank, one at a time, on ihe regular probe mechanism, were bom- 
 barded with a large deuteron beam for about 1 to 3 minutes, removed from the tank and radioauto- 
 graphs were taken to determine where the beam was hitting. The targets differed only in the width 
 of the slot. These slot widths varied from 2 l/2 to 4 l/2 inches. 
 
 RESULTS 
 
 The autographs indicate a rapid spreading vertically of the beam at about 81 l/2 inches. This 
 agrees quite closely with the point at which n = 0.2 from magnetic measurements. The autographs 
 indicate that the vertical spreading is large enough so that most of the beam gets caught by the dee 
 at this point. (Prints of autographs appear on following pagei.) 
 
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 Figure 1. Sketch of target. 
 
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 Figure 2. 
 
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UNIVERSITY OF FLORIDA 
 
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