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Petrovski
Netherlands
16 Posts |
 Posted - 05/27/2016 : 13:17:37
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Tube power was set to 60kV and 50mA. Energy of the K-alpha is around 18 keV. Source was about one meter away from the 320+. I noticed that the radiation was detected instantly after opening the tube shutter, and stabilized around 5000 CPM after 30 seconds. It took the 320+ a while (over a minute) to cool down and detection levels returned to background.
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Sorry no intensity graph, forgot to set the logger function to take a sample every second. |
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ZLM
1261 Posts |
Posted - 05/27/2016 : 22:45:05
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Great!
Can you provide detailed information on how you did that? |
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| Reply #2
Petrovski
Netherlands
16 Posts |
Posted - 05/29/2016 : 09:37:41
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Well, it's simply lying at the bottom of the enclosure of an X-ray diffractometer (at my work). I can choose between multiple X-ray tube anode materials, and can control the HT generator's power.
I'll repeat this test with data logging set to 1 second interval, I'm sure it will produce an interesting graph. |
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| Reply #3
Petrovski
Netherlands
16 Posts |
Posted - 05/30/2016 : 08:24:02
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Today I've repeated the test. I've put the 320-Plus on a sample stage so it was now ~10 cm away from the X-ray tube's aperture:
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I started again with the tube at max power (60kV/50mA) but as soon as I opened the shutter the 320-Plus saturated and the firmware rebooted.
So I lowered the power to 15/5 and checked the 320-Plus's response while I slowly increased the power. At 40/20 it was well in the 30k CPM range:
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The logged data does not reflect the experiment however. The max CPM on display is not logged, and also it does not show the increase of CPM while I increased the tube power:
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If I had to guess, it seems the firmware was too busy detecting radiation and the data logger task got low priority. Perhaps someone from GQ can confirm this?
Update: actually on a logarithmic scale you can see the first power ramp-up. But after that, none:
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Edited by - Petrovski on 05/30/2016 09:08:57 |
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| Reply #4
Distelzombie
Germany
202 Posts |
Posted - 06/01/2016 : 12:50:58
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| Could it be affected by some electromagnetic radiation? (it can be, I tested it) |
GMC-300E+ V4.20 with sbt-11a alpha tube
My statements are "stuff-a-hobbyist-says" and not in any way professional. |
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| Reply #5
ZLM
1261 Posts |
Posted - 06/01/2016 : 23:46:40
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Petrovski: What is your GMC-320 firmware version? The latest version should take care the task priority between counting ,data logging and display task. The counting task always be a highest priority task. |
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| Reply #6
Petrovski
Netherlands
16 Posts |
Posted - 06/02/2016 : 11:11:04
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@ Distelzombie: you mean like EMC interference? Could be, but since it's in an radiation tight enclosure I'm pretty sure it's just X-rays and the GMC itself in there.
@ ZLM: I have revision 4.12. |
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| Reply #7
Distelzombie
Germany
202 Posts |
Posted - 06/06/2016 : 12:33:38
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| Try to build a faraday cage. I once made one that worked great using a sieve and some cardboard with aluminum foil around. |
GMC-300E+ V4.20 with sbt-11a alpha tube
My statements are "stuff-a-hobbyist-says" and not in any way professional. |
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| Reply #8
Petrovski
Netherlands
16 Posts |
Posted - 06/07/2016 : 10:58:59
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| First I'll try the experiment again with new firmware. I've sent an email to GQ customer support. |
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Topic |
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GMC 320 Plus vs X-ray tube with Mo anode
