Study On Thermal Effect Inhibition Based On Surface Polishing Of Ion Beams

The residence time of the ion source at each point on the surface of the optical element is different,and the phenomenon that the surface removal rate of the ion beam on the optical element changes with time during the temperature rise stage is called "thermal effect".Through the uniform line sweep removal experiment of K9 optical components,the stacking spacing is2.5mm,and the total processing time is 500 s.After testing by zygo interferometer,it can be seen that the removal amount of K9 optical element gradually increased from 200 nm to 480 nm.And in the uniform surface sweep removal experiment of K9 optical element,it is found that the removal amount in the area just bombarded by the ion beam is significantly lower than that in other areas.In this paper,the influence of "thermal effect" on optical components in the processing process is studied and the method of suppressing the thermal effect is sought.In the process of exploring the ion beam machining workpiece,the thermal analysis model is firstly established,and the temperature field simulation of the model is carried out by means of transient heat transfer.The temperature field changes on the surface of K9 optical elements under several different processing forms of fixed-point bombardment,uniform line scan and uniform surface scan were investigated.The relationship between temperature and removal rate is established according to its surface temperature change.Using the temperature sensor,measure the temperature change on the surface of the K9 optical element during processing,and verify the correctness of the simulation of the surface temperature field of the K9 optical element.Attach the temperature sensor to the unprocessed side（back）of the K9 optic.The temperature before and after processing is quite different,and the temperature shows an upward trend in the whole processing process.When the surface of the K9 optical element reaches the temperature equilibrium,the difference between the simulated temperature and the actual measured temperature is small,and the temperature difference is within 2 ℃.The increased dwell time is found using the Romberg quadrature formula and the variable upper bound integration algorithm.Compensation for the under-removed portion caused by temperature effects.As well as adopting batch processing of the temperature-affected area of the K9 optical element to reduce the impact of temperature effects.Experimental verification of compensation means.Perform a uniform line sweep experiment on the K9 optical element to obtain the surface shape of the part removed by the line sweep.The etching amount is basically the same,stable at about 480 nm.Compensation means are greatly improved for reducing the influence of temperature effects.