Paper  Title  Page 

TUPAN083  SpaceCharge Neutralization in Ion Undulator Linear Accelerator  1565 


RF undulator accelerator (UNDULACRF) is suggested as an initial part of high intensity ion linac*. Such accelerator can be realized in periodical IH structure where a field has no spatial harmonics in synchronism with the beam. Ion beam is accelerated by the combined field of two nonsynchronous harmonics. Accelerating force value is proportional to squared particle charge. Transmission coefficient and accelerating gradient for low velocity ions with the identical sign of charge are the same as in RFQ. The limit beam current can be larger in this type accelerator. Its value was calculated earlier in paper **. But the beam intensity can be substantially increased in UNDULAC by using space charge neutralization of positive and negative charged ions. In UNDULAC positive and negative ions can be accelerated simultaneously within the same bunch. The process of acceleration and focusing of oppositely charged ions with the identical chargetomass ratio is discussed in this paper.
* E. S. Masunov, Technical Physics, V. 46, 11, 2001, pp. 14331436.**E. S. Masunov, S. M. Polozov, NIM., A 558, 2006, pp. 184187. 

TUPAN084  Using Smooth Approximation for Beam Dynamics Investigation in Superconducting Linac  1568 


The superconducting linac consists of some different classes of the identical cavities. The each cavity based on a superconducting structure with a high accelerating gradient. The distance between the cavities is equal to acceleration structure period L. By specific phasing of the RF cavities one can provide a stable particle motion in the whole accelerator. The ion dynamics in such periodic structure is complicated. The reference particle coordinate and momentum can be represented as a sum of a smooth motion term and a fast oscillation term, a period of which is equal to L. Three dimensional equation of motion for ion beam in the Hamiltonian form is derived in the smooth approximation for superconducting linac. The longitudinal acceptance and maximum energy width in a bunch are found by means of the effective potential function. The general conditions applicability of a smooth approximation to given electrodynamic problem is formulated. The nonlinear ion beam dynamics is investigated in such accelerated structure. 