Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.naic.edu/~phil/hardware/xmiter430/Arecibo_Landauer_Report_April%202012.pdf Дата изменения: Wed Oct 29 16:12:10 2014 Дата индексирования: Mon Apr 11 20:47:34 2016 Кодировка:

May 14, 2012 Ionizing Radiation Dosimeter Review; Arecibo; April 2012 by Wesley R. Van Pelt, PhD, CIH, CHP, RSO Various locations near the klystron RF tubes in the Gregorian dome on the platform and in the 430 MHz transmitter room are monitored with monthly dosimeter badges to measure levels of ionizing radiation. The Landauer radiation dosimeter badges were put in place on 1 April 2012 by Wilson Arias. The nominal monthly period was 5 April thru 4 May 2012. The Landauer dosimeter report for this period is attached. All readings were minimal or below 3 mrem except for badges 8, 9 and 10 which were located closest to the 430 MHz klystron tubes in the RF transmitter room. The monthly radiation readings were 95, 11 and 135 mrem respectively. These areas are not occupied when the 430 MHz RF transmitters are on. A review of the Observatory Telescope Schedule shows that the 430 MHz transmitter was scheduled to be operating during 5 of the days during this period. A radiation dose of 135 mrem is not dangerous and is below the 5,000 mrem annual limit allowed for occupational workers. (Note again that this area is not occupied and there is no reason to believe that any person received a radiation dose.) However, these results indicate that there is a detectable level of ionizing radiation produced in the immediate vicinity of the klystron cabinet when they are powered up. Recommendations: 1. Wilson check the operating. will serve Arias or Angel Vazquez should use the Victoreen ion chamber radiation meter to areas immediately outside the transmitter room when the 430 MHz transmitters are I do not expect any detectable readings based on the dosimeter reports. However, this to confirm the levels of radiation in occupiable areas.

2. It should be re-emphasized to Arecibo staff and visiting scientists that the 430 MHz transmitter room should not be occupied when the klystrons are powered. 3. The Landauer dosimeter program should remain in effect for at least 3-4 more months to verify the ionizing radiation levels from the klystron tubes.

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Figure 4 The 430 MHz Klystron cabinet with yellow caution radiation signs.

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