Walker TG

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Subject A 120 GEV/C UNSEPARATED BEAM USING SMALL APERTURE COMPONENTS The object of this work was to investigate the properties of a high momentum unseparated beam suitable for counter and spark chamber experiments using the four feet long, one inch diameter quadrupoles suggested by Maschkei for use in a general purpose EPB target station. The beam is of a simple two-stage design with a momentum slit at the intermediate focus and momentum recombination at the final focus. The beam is shown schematically in Fig. 1. Matching and 2 tracking were performed using the computer program TRAMP. The parameters of the magnetic elements are given in Table I. One-inch quadrupoles are used to define the acceptance at the target. Down- stream two-inch diameter quadrupoles are required to contain the off- momentum rays of l 1% Ap/p. If a momentum bite greater than 2 % is required the apertures will correspondingly have to be increased. The quadrupoles are about four feet long. The bending magnets have 2” X 6” apertures and are about 16 feet long. Phase space distributions and solid angle acceptances were com- 3 puted using IPSO FACTO. A slit of about one inch is used at the intermediate focus to define the momentum to +tl%. The beam distribu- tions at the intermediate and final foci are shown on Figs. 2 and 3. The effective solid angle subtended at the target by the beam is on Fig. 4. The integrated effective solid angle is 7.3 microsteradian -2- FN-157 2254 per cent with a 2% momentum bite. The flux of pions at the final focus depends on the production angle at the target but as long as this is with 500/p. = 4 mrad, then fluxes of several i06 pions per 10 12 protons on the target can be expected using the CKP4 estimates. The main properties of the beam are listed in Table II. An ade- quate beam can clearly be designed using small aperture components. The savings in manufacturing cost and power consumption are con- siderable. -3- FN-157 2254 REFERENCES iA. Maschke, NAL Memo (1967). ‘TRAMP, J. W. Gardner and D. Whiteside, Rutherford Laboratory report NIRL/M/Zi (1961). 3 IPSO FACTO, N. M. King and P. W. Simpson, Rutherford Laboratory report, RHEL/Ri03 (1965). 4 Cocconi, Koester, and Perkins, Lawrence Radiation Laboratory report UCRL-10022 (1961). FIGURE CAPTIONS Fig. 1. Beam layout and ray diagram for 120 GeV/c beam. Note the different scales. Fig. 2. Phase space at the intermediate focus. Fig. 3. Phase space at the final focus. Fig. 4. Momentum acceptance of the beam. Effective solid angle as a function of momentum. -4- FN-157 2254 7abit i. E--1- asxx:s 3lement :.:a@etic ?sld I Aperture 2, ix-i 7510 gJcn L25 cm x '2.5 cm dim % ?x 6100 gym, 125 an x 2.5 cm dim >.:l-iO 4600 g 500 cm x 15 cm x j cn -2 i 4> -v Gj '6 ;,;l-za ./q i, " 7;: 3H DH FH FIi lx 5750 ;]a. 6950 &l/c" 6950 E/cm 5780 dcm 4600 g 6100 gym 7jiO dCZ 125 cm x 5 cm dim 125 cn x 5 cm diam 125 cm x 5 cm dim i25 cm x j cm diam 500 cr. x 15 cn x 5 cr. 125 cn x 5 cm dim j 125 cn x j err. dim I -5- FN-157 2254 Table 2. Main Properties of the Beam Design momentum = 120 w/c Length = 2Q3 m. I." quadmpoles 2" quadmpoles 16' magnets 2" x b” Magnifications at M'M Intermediate focus M'V Dispersion at int. focus Momentum slit Momentum acceptance Magnifications at MH final focus Mv Assumed EPB size Spot size at final focus for + 1s Ap/p Effective solid angle = 2 = b =x) = 1.1 = 1.2 = 1.25 cm per 1% Ap/p = + 1.4 cm = L 1% = 1.0 = 1.0 = 0.2j h x 0.25 y cn? = 0.4 h x 0.6" cm2 = 7.3 bster per cent &p/p Estimated pion flux at 0' using CKP - 3 lo6 per 101' protons and target efficiency of 0.3 -b- ra FN-157 2254 )r t-8 L I i mu - - I I I I 0 3 E z! al -;- X’ mrad. FN-157 2254 --I 1 I X I It I I I I 6 \r I I 1 ’ -1 1 cm. \I P, - 1% y” -1 tqj + 1 “f. ’ mrad . Y c m. F I G. 2 -8- FN-157 2254 0 cr, CI E’ IL v d >\ s a E’ :A -5-l I I -- - #w- , I A I 1; ---___ I/ - - / - I Li I- Y --- I ‘-6- 

A 120-GEV/C UNSEPARATED BEAM USING SMALL APERTURE COMPONENTS

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