[Tpe] TPE shielding

[David Kashy]

Hi Larry,
Is this wall 10' high or wide?
If it is 10 ft wide then I guess we need to start it above the floor 
level and need to design a beam structure to support it.

If it is 10 ft tall we will still need to design a structure to keep it 
from toppling.

This wall will weight about 8000 lbs (similar to HYCAL) not a trivial 
load and thus we must do it correctly.

Thanks
Dave



On 1/26/2011 4:55 PM, Larry Weinstein wrote:
> Dear Folks,
>
> Recommendation: In order to be very conservative, build a concrete 
> wall on the beam left side of the collimator box, frascati magnet 1, 
> and PS magnet.  The wall would be about 10' x 5' x 1' and require 200 
> blocks.  It should be built during the next extended down time 
> (Tuesday?) so as not to interfere with taking data.
>
> Details:  I spoke to Pavel Degtiarenko, the radiation and shielding 
> expert.  He says that there is very little useful data about the 
> effect of radiation on electronics because the response of electronics 
> to radiation is highly variable.  He also noted that the existing BPM 
> amplifiers have probably already suffered some radiation damage and 
> that this damage is cumulative.  He also said that most of the 
> radiation is probably high energy particles that can be shielded by a 
> shield wall (if we know the approximate source location.)
>
> This means that we probably want to add shielding to reduce the 
> probability of catastrophic BPM failure.
>
> RadCon gave us the badge readings today (thanks, Becky!).
>
> 66016 	331 	1' from top of Acc IOC rack 	
> 66017 	197 	2.5' from top of Acc IOC rack, in front of concrete wall
> 66018 	220 	2.5' from bottom of Acc IOC rack, in front of concrete wall
> 66019 	66 	2.5 from top of Acc IOC rack, behind concrete wall
> 66020 	73 	2' from bottom of Acc IOC rack, behind concrete wall
> 66023 	92 	on ioc ptarg 	
> 	
> 	
> 66024 	254 	in front of new lead wall, 5' from floor 	
> 66025 	191 	L1-15 on left (upstream) side of IOC 	
> 66026 	632 	on railing opposite PS 	
> 	
> 66027 	230 	upstream, beam side of lead wall on ioctorus
> 66028 	126 	downstream, outside of lead wall on ioc torus
>
> The first column is the badge number, the second is the radiation 
> dose, and the third is the location.
>
> A few notes: Badge 66026 with a reading of 632 mr is located where the 
> radcon photon probe was located before 1/20, on the railing of the 
> space frame close to the pair spectrometer.  The probe was reading 
> about 50 mr/hr at that location.
>
> Badge 66019, behind the concrete wall, is located directly on top of 
> the accelerator BPM amplifiers and right next to the radcon photon 
> probe which is currently reading 5 mr/hr.  This is consistent with 
> badge 66026.
>
> badges 66016, 7, and 8 are located on the accelerator BPM amplifier 
> rack.  The highest one (66016) has the highest dose and has much less 
> of the lead shielding on the lead wall between it and the beam line.  
> The concrete wall (either 6" or 12") reduces the rate from about 200 
> mr to 70 mr (comparing badges 17 and 18 with 19 and 20).  (Note that 
> the badges were placed before the BPE shielding was added.)
>
> The maximum thickness of the lead wall reduces the dose from 254 
> (badge 66024) to 92 (badge 66023).
>
> The radiation level is not much less a little further down-beam on 
> rack L1-15 (191 mr at badge 25).
>
> The dose decreases about a factor of two between the upstream beam 
> side of the lead wall on ioctorus to the downstream outside of the 
> lead wall.
>
> Summary: The dose at iocptarg, ioctorus and the accelerator BPM 
> amplifiers are within a factor of two.  The shielding reduces the dose 
> significantly.
>
> There is floor space or floor weight capacity to place any more 
> shielding near the racks.  THis means that the only place to add 
> shielding is near the source.  Since the source probably includes the 
> collimator box, convertor and chicane, we should build a concrete wall 
> on the beam left side from the PS magnet going as far upstream as 
> possible.
>
> -- 
> 				Sincerely,
> 				Larry
>
> -----------------------------------------------------------
> Lawrence Weinstein
> University Professor
> Physics Department
> Old Dominion University
> Norfolk, VA 23529
> 757 683 5803
> 757 683 3038 (fax)
> weinstein at odu.edu  <mailto:weinstein at odu.edu>
> http://www.lions.odu.edu/~lweinste/  <http://www.lions.odu.edu/%7Elweinste/>

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