A few sessions ago I had a great idea to transfer the almost instant response times of the RF CO2 laser to the glass tube laser. The main response delay with a glass tube is whenever you switch the tube off there is a restart delay. ALL manufactureres promise a switch on response time of less than 1ms.There is no physics reason for the pixel to pixel current flow to be other than almost instant, provided the glass tube never switches off. If you switch the beam off then there are TWO delay issues. First is that that 1ms start up to create the high voltage and secondly the tube has a weird performance characteristic called preionization which adds more delay. With dithered photo engraving the tube is continually switcing on and off because black pixels = ON and white pixels =OFF. White(greyscale 255) will ALWAYS act as a OFF signal. Thus, after and OFF, subsequent pixel demand cannot be satisfied until the tube is back to full power. My idea was to dither an image (just black and white pixels) and then convert it to grayscale where black pixels =0 and white pixels = 255. I then adjusted the image output so that I removed the 255 white pixels by limiting the image to 254. No one except the controller would notice the missing 255. This in fact, does prevented the tube from switching off during a scan and shoiuld have given me the instant current flow changes I was expecting.

BIG disappointment. I turns out on closer inspection of the signals, the controller is very happy to react instantly and never issue a "switch-off" signall but the current control circuit within the HV power supply is VERY heavily damped and what comes out is but a shadow of the demand signal going in.

I discussed this issue with Cloudray to see if they were aware of this performance problem. They were not. My next question asked if there were any differences between HV power supply manufacturers.? Again the answer was unkown. However it prompted Cloudray to offer me two different HV power supply designs to compare against my basic MYJG design. The results were rather suprising

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