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[lcdds 263] Re: modified assembly scheme for GLD

Subject:   [lcdds 263] Re: modified assembly scheme for GLD
From:   山本 均 <yhitoshi@xxxxxxxxxxxxxxxx>
Date:   Mon, 11 Sep 2006 22:09:32 +0900

Dear Andrei, sugimoto-san, and all

    I am a bit concerned about the lack of electronic hut in the hall.
Where will it be? An extra space nearby the hall? On surface?


- Hitoshi

On 2006/09/07, at 9:29, Seryi, Andrei wrote:

>  Dear Sugimoto san and all,
> Could you please discuss if a modified scheme of
> GLD assembly, as shown in the file
> "questions_on_GLD_assembly.pdf", may be possible.
> In this case, it is assumed that central part of the
> detector can rotate before installation of the solenoid.
> It looks that the width of the collider hall may be
> reduced from 30m to 22m, giving significant savings
> in cost of hall, cranes, simplify support of beamlines,
> and reduce the need for beamline shielding.
> For comparison, the original GLD assembly scheme is also
> attached ("exphall060821.pdf").
> Also, the earlier questions of details of assembly,
> crane and shaft requirements (listed in the message below),
> still need to be discussed.
>  Best regards
>   Andrei
> -----Original Message-----
> From: Seryi, Andrei [mailto:seryi@xxxxxxxxxxxxxxxxx]
> Sent: Thursday, August 31, 2006 9:56 PM
> To: lcdds@xxxxxxxxxxxxxx
> Cc: Martin Gastal; Jean-Luc Baldy; Vic Kuchler
> Subject: [lcdds 255] Re: Minutes of 2nd Detector-assembly meeting
>  Dear Sugimoto san and all,
> Optimization of 15m to 16-17m shaft, to accommodate
> the elevator is probably possible.
> The crane vehicle as shown in CMS movie is probably
> not the only possibility. We will ask CFS colleagues
> about this.
> For the wall in the hall, I am not sure if it can help
> to make magnetic shielding. We were thinking to use just
> concrete wall, without much iron.
> What are the reasons to require magnetic shielding between
> detectors?
> I believe we need more analysis of cranes, hall size and
> details of assembly.
> Am I right that if you assume pure CMS style assembly, then
> for GLD one would need
>    ~20m shaft
>    2000t rented gantry crane on surface
>    ~20t movable crane on surface
>    ~20t crane in the hall
> And with modified CMS assembly, one would need
>    ~15m shaft
>    ~400t movable crane on surface
>    ~400t movable crane in the hall
> I think we need to compare the cost and schedule in details.
> In particular, we need to take into account that:
>   - most of procedure underground take longer than on surface
>   - hall size requirements (especially height) may be
>    larger for 400t crane vs 20t
> We requested the GDE management to create a mechanism to provide
> parts of the CFS costs for such optimization. Hope this will happen,
> but if not, we have to do it anyway.
> For the hall width -- if the center part of the detector
> can be rotated 90deg before insertion of solenoid, can
> it reduce the required width?
>  Best regards
>   Andrei
> -----Original Message-----
> From: Yasuhiro Sugimoto [mailto:yasuhiro.sugimoto@xxxxxx]
> Sent: Tuesday, August 29, 2006 6:54 PM
> To: lcdds@xxxxxxxxxxxxxx
> Subject: [lcdds 252] Minutes of 2nd Detector-assembly meeting
> GLD detector assembly task-force meeting minutes
>    date:29 Aug. 2006
>    attendants: A.Miyamoto, T.Omori, Y.Sugimoto, T.Tauchi, H.Yamaoka
> 1. Discussion on Andrei's  questions
>    1-1.
>>  Is it possible to equip the 15m collider hall shaft
>> with elevator and stairs for personnel access as well?
>> (motivation: removing the 9m access shaft near IP and
>> relocating them to BSY)
>       It seems too tight to share the 15m shaft with elevator
> and stairs.  A larger diameter shaft (16 -- 17m) with elevator
> and stairs is preferable.
>      In order to construct the overhead crane (and others)
> in the cavern,  a tall  crane vehicle has to be lowered beforehand.
> We have to care  about the length of the crane vehicle when
> we decide the shaft diameter.
>    1-2.
>>  Is the following suggestion acceptable:
>> Include into the BDS cost only the cost of minimum size
>> collider hall and small shaft.
>> (for example 100L*20W*30H m^3 hall, two 9m shafts, no wall)
>> The cost difference from the minimal configuration is
>> included into detector cost.
>> (E.g. delta cost of increasing the shafts to 15m and
>> increasing the hall size, and adding the shielding wall)
>>  Motivation: more clear comparison of detectors and
>> streamlining the overall optimization.
>       This issue has already been discussed in the lcdds mailing list.
> We confirmed that we should assume the size of the experimental hall
> and the diameter of the shaft as we (GLD)  think necessary.
>       We think we may need the wall between two experimental halls  for
> radiation safety reason.   The radiation control  area is classified
> into several levels. At KEK, for example, the classification is
> as follows (I don't know the proper English words, though);
> Off-limits area  (No one can enter) :  > 10 rem/h
> Restricted area (Special permission required) : > 2 mrem/h
> General controlled area (Need qualification and ID card) : > 150  
> micro-rem/h
> bra-bra-bra-
>       If only the researchers work in the hall  when beam is on,  then
> the radiation level of  less than 10 rem/h would be OK and no wall
> would be necessary. However, when one detector gets wrong and
> the maintenance work by company people is necessary, the area
> should be the "General controlled area", i.e., the radiation level
> should be less than 2 mrem/h. To achieve this level with the other
> detector running,  we may need the wall between the two experimental
> areas.
>       The wall could  work as a magnetic shield as well as radiation  
> shield.
> If one detector  makes a strong leakage field, the wall  might be
> necessary.
>       The wall may not have to be as high as the experimental hall  
> itself.
> Anyway, we need more simulation work to get conclusion.
>    1-3.
>> In the Vancouver configuration there was an additional
>> service cavern (where detector equipment can be placed).
>> It may be the case that the hadron machines with their
>> higher event rate and fast triggers do need such cavern.
>> Can we remove this cavern and put all the detector equipment
>> and services in the experimental hall?
>       We could not find any reason to refuse the removal of the
> service cavern from the viewpoint of detector construction.
> However,  we are anxious about the removal of 9m shaft.
> If  accelerator components are lowered using the shaft in the
> experimental hall,  it could cause the conflict  with detector
> assembly.
> 2. Discussion on crane capability
>      We discussed about the construction procedure of
> the iron structure.  However, it is not clear yet whether
> we can construct it satisfactorily without 400t crane
> in the experimental hall. So we would like to stick to the
> 400t crane option.
>       A Japanese company (IUK) can provide us with 400t crane
> "off the shelf".
> ----------------------------------------------------------------------- 
> --------
> Yasuhiro Sugimoto
> <exphall060821.pdf><questions_on_GLD_assembly.pdf>