Date: Thu, 7 Mar 2002 12:15:35 +0900 From: Toru Tsuboyama Subject: RADFET irradiation Dear colleagues, Ishino san told me that we can irradiate at TIT on March 14 from 10:00 AM. Preparations --Encapsulation --Initial test of RADFETs -- Aminogray calibration --Setting up monitor system. --Converter I would like to know who can join the test. Best regards, Toru Tsuboyama --------------------------------------------------------------------------- On Sat, 13 Oct 2001, Samo Stanic wrote: > Dear Marc, > > as we talked when you were in Tsukuba recently, could you dig up all > information that you can on the RadFET callibration experiment at UH in > 1999. We are interested mostly in what the setup was like, how exactly was > the dose rate known by the irradiation facility (did you check that by > doing your own dosimetry?), was there any material in front of RadFETs > during irradiation etc. > > We would also like to know what kind of RadFET reader you were using, what > were the voltages applied to the RadFETs etc. > > Any kind if information will be welcome. > > Thanks, Samo From rosen@phys.hawaii.edu Fri Nov 9 11:05:12 2001 Date: Thu, 8 Nov 2001 15:41:03 -1000 (HST) From: Marc Rosen To: Samo Stanic Subject: Re: RadFET callibration experiment at UH in 1999 Hi Samo and Tsuboyama-san, Sorry this reply has taken so long, but I finally have some information for you. I was able to meet with one of our former student techs who set up for RadFET runs, but did not look at any of the data. I was also able to talk to the professor who runs the fruit irradiation facility, where the work was done. The RadFET board was mounted on an aluminum frame and ~6mm thick aluminum was used as the structural member behind the board. The aluminum frame that held the board was then placed inside of a rectangular (in cross section) stainless steel box that has ~10mm thick walls. There were a total of four irradiation sources, two on each (long) side of the SS box and placed about 3cm from the outside wall of the box. Thus the board is irradiated from both front and back. The inside of the box is ~18cm across (in the narrow direction) and the RadFET board was mounted in about the center. Hence the board was ~13cm from each pair of sources. The front of the board had ~10mm of SS between itself and the sources, and the back of the board had ~6mm of aluminum plus ~10mm of SS between itself and the pair of sources. In the beginning there were vast plans for running active environmental monitoring as well as power down to the board during irradiation. The SS box tended to leak when a cover was used that allowed for cable feed-thrus. When a solid cover was used there were no leaks. Hence the tests were conducted w/o any power and/or real time monitoring. The accumulated dose was done by both a basic calculation and also the use of a RadFET reader. The calculation was a simple product of the integrated time x the output of the sources (based on a time-decay table provided at the facility). Following a run where the dose was calculated (as above), the dose was then read from the RadFET using a reader that Gary designed based on some UK and Australian papers. Apparently the RadFETs were too noisy to read immediately following a run, and so one day of annealing time was implemented before the reader was used. There are schematics for the reader in Gary's (former) lab. All of the data seems to be stored on a PC that no one (who is currently around) can log onto. I hope this helps your cause. You are welcome to ask more questions, and I may or may not be able to provide additional information. I personally never participated in this experiment. Regards, Marc