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[lcdds 258] Re: GLD Experimental hall

Subject:   [lcdds 258] Re: GLD Experimental hall
From:   Yasuhiro Sugimoto <yasuhiro.sugimoto@xxxxxx>
Date:   Wed, 6 Sep 2006 16:50:22 +0900

Dear Andrei, and all,

    I have studied another model on the leakage field.
By changing the configuration of the iron yoke and
using more precise data of permeability which I got
from Yamaoka-san, the leakage field at z=10m is
reduced from ~100 Gauss to ~70 Gauss without
compensation coils.  With a new  configuration of
compensation coils,  L1 (r=1.5 m at z=10m, 6kAT) and
L2  (r=2.5m at z=12m, 4.5kAT),  the leakage field
is reduced  well below 50 Gauss for z>10m.
Please look  at the attached file.  I think these two rings
of coil do not conflict with accelerator components.

Best regards,

Yasuhiro Sugimoto
KEK


>Dear  Sugimoto san,
>
>Thank you for this study. I somehow thought that the
>coils would be more close to the detector,
>but they are over the beamline...
>There could be a difficulty to place these coils
>in practice, due to interference with packman,
>or with tunnel or other things. This needs to be
>studied.
>
>It probably would not work, but what if one would place
>one more thin layer or iron ~0.5-1m around the detector?
>
>One more question which you probably already considered--
>is it possible to use double solenoid to return the flux
>within the detector instead of iron, like in forth concept?
>Of course it is totally different optimization -- the cost
>of coils is increased and cost of iron is reduced.
>I do not know where the optimum is.
>
>  Best regards
>   Andrei
>
>
>-----Original Message-----
>From: Yasuhiro Sugimoto [mailto:yasuhiro.sugimoto@xxxxxx]
>Sent: Thursday, August 31, 2006 3:02 AM
>To: lcdds@xxxxxxxxxxxxxx
>Subject: [lcdds 253] Re: GLD Experimental hall
>
>Dear Andrei,
>
>    I have calculated the leakage field of GLD
>with reduced  iron thickness of the return yoke
>including compensation coil.
>     I  put 8 rings of coil   with 1.5m intervals
>starting from  z=10m.  The diameter of the
>coil is about 2m, and the current  for each
>coil  was adjusted depending on the z-position.
>    The result is shown in the attached file.
>The colored region of the 1st page has
>the field strength less than 50 Gauss.
>The second page compares the leakage field
>along the beam line with and without the
>compensation coil.
>    The compensation coil does not require
>large current, and  normal conducting
>coil without water cooling would be enough.
>
>    How do you think on this result?
>
>Best regards,
>
>Yasuhiro Sugimoto
>KEK
>
>
>
>>   Dear Sugimoto san,
>>
>>The 2000t crane is rented and getting two cranes
>>is possible.  We need to ask what is the cost of
>>renting one crane for ~3 years or two cranes
>>for ~1.5years each. Maybe the cost is not much
>>different. I will ask.
>>
>>For the external field and its compensation by coils.
>>I worry that compensation would be not ideal and there
>>would be still regions with larger fields.
>>Could you include such compensating coil(s) into magnetic
>>model of the detector and show what level of compensation
>>would be possible?
>>
>>   Best regards
>>    Andrei

Attachment: exphall_coil.pdf
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