[Olympus] Background situation at DORIS

[Brinker, Frank]

Dear Salvatore,
I don't't think that the measurements I showed you are sufficient to
estimate the situation we'll have at the IP. One sees, that the rates
drop drastically when moving away from the last dipole. At Position E,
which is half way to the IP, that accumulated dose was 0.5 gray
integrated over a period of 30 days - from that one not expect any
problems. But that might be too simple, since after inserting the target
cell we'll have introduced a tight aperture which changes the situation
significantly.

The measurements had been done over about half a year. I send you a plot
which showes the integrated dose over the period in 2005, measured at 3
different positions. 

Best regards
Frank

>-----Original Message-----
>From: frullani at iss.infn.it [mailto:frullani at iss.infn.it] 
>Sent: Tuesday, October 12, 2010 1:06 AM
>To: Brinker, Frank
>Cc: frullani at iss.infn.it; olympus at mit.edu
>Subject: RE: [Olympus] Background situation at DORIS
>
>
>Dear Frank,
>thank you for the information.
>One comment and one request.
>Comment: if measurements are taken with different detector 
>systems (in the photo a rather big volume ionization chamber 
>in position D is shown and you mention also TLD that are 
>usually much more small) and in the area there is a large 
>radiation field gradient we could have difficulties in 
>interpreting the measurements. Our problem is radiation field 
>in a small area (the size of electronics chips) and we need 
>information of the highest possible field during normal 
>condition operation mediated in volumes of this size.
>Question: have the measurements been taken for a long enough 
>period to be considered representative of a normal operation 
>situation ? Have been in that period some beam losts and other 
>possible peculiar but normally occurring  situations that are 
>at origin of higher radiation field? In conclusion if we are 
>confident that 10 or 100 Gray/day is a representative number 
>we can start to think with this numbers in mind a consider a 3 
>months period. If not, with possibility that these number must 
>be revisited going significatively higher or lower, we have to 
>investigate the problem of measurements more deeply. This is 
>all for the moment. Have a good day of work, and not only .. Salvatore
>> Dear collegues,
>> I got now the measurements from our RF group. They installed 
>radiation 
>> detectors and TLDs under the beam pipe in the RF straight behind the 
>> last dipole at different positions. Attached you'll find the dosis 
>> rates and the positions. Plotted is the log of the rates, since they 
>> are surprisingly different by several orders of magnitude.
>>
>> Best regards,
>> Frank
>>
>>>-----Original Message-----
>>>From: olympus-bounces at mit.edu [mailto:olympus-bounces at mit.edu] On 
>>>Behalf Of frullani at iss.infn.it
>>>Sent: Monday, September 27, 2010 9:42 AM
>>>To: Alexander Winnebeck
>>>Cc: olympus at mit.edu
>>>Subject: Re: [Olympus] Background situation at DORIS
>>>
>>>
>>>Thank you Alexander,
>>>for very informative measurements.
>>>Would be possible during the foreseen next measurements to put also, 
>>>with help of DESY radiprotection group, some TLD (or similar 
>devices) 
>>>chips to have a measuremnt of radiation field integrated 
>over time in 
>>>Gray ? This would allow a quantitative appreciation of the hardness 
>>>level needed for the electronics near the interaction point. 
>Thanks a 
>>>lot. Salvatore
>>>> Dear colleagues,
>>>>
>>>> attached you can find some results of the background 
>measurements at 
>>>> DORIS in the future interaction region of OLYMPUS. I could
>>>learn that
>>>> we don't need to have fear of the beam injection at DORIS, 
>but beam 
>>>> losses are an issue. Thanks to Juergen, who helped me to 
>install the 
>>>> detectors, Philipp for supporting a DAQ, and Frank for giving me 
>>>> access to the DORIS data base.
>>>>
>>>>
>>>> Best regards,
>>>>
>>>> Alexander
>>>>
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