| Ion source injected Interdigital H mode linac has great potential to accelerate high current particle beam with high efficiency and low power.It is suitable for commercial production.Reaserch on this area now meet bottleneck,the current(transmission efficiency)is not large enough for practical application.Beam energy of some prototype which has been constructed is about hundreds keV.In order to tap the potential and locate the problems,this dissertation is concentrated on the simulation,design,fabrication and conditioning of high energy.long sequence,and high transimission ion source injected IH linac.The main research contents and conclusions of this dissertation include the following aspects.By optimization of the alternating phase sequence,the transmission canbe increased.A transmission of 38%has been obtained with simulation reasult,which fullfill the practicle requirement.Detailed investigation shows that high shunt impedance came from thin drift tube and smaller cavity diameter,both reduce the surface current exhausation.The shunt impedance of ion source injected IH cavity is much higher than RFQ injected IH cavity.Even with ? as high as 0.065,the shunt impedance is about 360M?/m,the effect shunt impedance is about 150M ?/m.The real power consumption is about 45kW to acceletrate proton from 40keV to 2.0MeV.Simulation and test both shows that cavity could work with high duty factor with simple cooling design.The highest temperature appears at the front drift tube.Without injected water cooling,the temperature rise is about 50 Celsius degree.With injected water cooling,the caity could work at CW mode.The fabrication and field measurement shows that the lenth of drift tubes and distence between them is a critical problem to obtain the correct field distribution and cavity frequence.With combination of some methods,the field error canbe remarkably eliminated.Preliminary beam measurement shows that part beam hase been effectively accelerated though the cavity. |
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