Difference between revisions of "X-Ray setup calibration (170131)"
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Calibration of X-Ray setup was performed using [http://www.raysafe.com/en/Products/Equipment/RaySafe%20ThinX#Downloads link RaySafe ThinX Rad] dosimeter (data sheet in link) | Calibration of X-Ray setup was performed using [http://www.raysafe.com/en/Products/Equipment/RaySafe%20ThinX#Downloads link RaySafe ThinX Rad] dosimeter (data sheet in link) | ||
| − | [[File:dosim.jpg]] | + | [[File:dosim.jpg|frameless|center|upright=0.85]] |
Unfortunately, we discovered that dose of irradiation is not uniform in horizontal plane and some area were over the dosimeter limit. We were able to measure dose placing directly under the source of x-rays so we decided to calibrate setup only in center of each shelf (there are 9 shelves). | Unfortunately, we discovered that dose of irradiation is not uniform in horizontal plane and some area were over the dosimeter limit. We were able to measure dose placing directly under the source of x-rays so we decided to calibrate setup only in center of each shelf (there are 9 shelves). | ||
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Dosimeter has a limit of exposure time so we set the X-Ray setup to 6s. We notice dosimeter shows irradiation time to be ~7.5s (additional raise/dead time). Dosimeter shows estimation for a minute and those values are in the plots. Below there is a table with all results. Measuring area of dosimeter is circle with 15mm radius. | Dosimeter has a limit of exposure time so we set the X-Ray setup to 6s. We notice dosimeter shows irradiation time to be ~7.5s (additional raise/dead time). Dosimeter shows estimation for a minute and those values are in the plots. Below there is a table with all results. Measuring area of dosimeter is circle with 15mm radius. | ||
| − | [[File:XRay_dose.png]] | + | [[File:XRay_dose.png|frameless|center|upright=0.85]] |
''Distance (shelf) dependence of the dose rate in the x-ray machine. The dosimeter was always placed at the center of the shelf, and measured the doses at 3 different currents (1.0, 4.0, and 6.2mA)'' | ''Distance (shelf) dependence of the dose rate in the x-ray machine. The dosimeter was always placed at the center of the shelf, and measured the doses at 3 different currents (1.0, 4.0, and 6.2mA)'' | ||
| − | [[File:coeffs_mA.png]] | + | [[File:coeffs_mA.png|frameless|center|upright=0.85]] |
''Linearity of dose rate as a function of current in X-Ray'' | ''Linearity of dose rate as a function of current in X-Ray'' | ||
Revision as of 21:11, 8 February 2017
Calibration of X-Ray setup was performed using link RaySafe ThinX Rad dosimeter (data sheet in link)
Unfortunately, we discovered that dose of irradiation is not uniform in horizontal plane and some area were over the dosimeter limit. We were able to measure dose placing directly under the source of x-rays so we decided to calibrate setup only in center of each shelf (there are 9 shelves).
Dosimeter has a limit of exposure time so we set the X-Ray setup to 6s. We notice dosimeter shows irradiation time to be ~7.5s (additional raise/dead time). Dosimeter shows estimation for a minute and those values are in the plots. Below there is a table with all results. Measuring area of dosimeter is circle with 15mm radius.
Distance (shelf) dependence of the dose rate in the x-ray machine. The dosimeter was always placed at the center of the shelf, and measured the doses at 3 different currents (1.0, 4.0, and 6.2mA)
Linearity of dose rate as a function of current in X-Ray
The dose rate follows very nicely the 1/d^2 rule (for distances greater than 20cm, i.e., shelves position from 1 to 8). Also, the dose rate is very linear with current set in the instrument.
Raw data:
