[Halld-jlab] Cable Length - Final Check

Wed May 25 10:38:10 EDT 2011

Hi Elton,

Thanks for the great feedback. My comments follow:

Elton Smith wrote:
> Hi Fernando,
>
> Thanks for pushing these procurements through. I am looking 
> particularly at the Bcal and Fcal requirements, but some of my 
> comments are more general:
>
> 1. Belden 9907 is listed in the Belden catalog as RG58/U type (not 
> RG58A/U).
Belden 9907 is classified as RG-58A/U on the data sheet I have from Belden.

> 2. Labels: At the time cables are ordered, we should also have them 
> labeled. It is much easier to have quality labels attached at the time 
> they are fabricated because the connector is not yet on, and this 
> allows for sturdy labels to be placed without going over the 
> connector. I believe you already have labeling scheme which has been 
> reviewed and could be used for all cables, although it might be useful 
> to check the labels one last time. It is also useful to include the 
> length of the cable on the label.
> 2a. Labels for the Fcal cables should be coordinated with the Fcal 
> cables and labeling which already exists at IU.

The cables will be labeled with their length. Unfortunately, the 
labeling scheme is not yet finalized. On the bright side, there are 
quality labels on the market that can be applied at a later date.
> 3. Discussion on spares: We should consider the strategy here, and 
> comments/suggestions are welcome.  In the final installation we will 
> want all cables to be correctly labeled. Therefore, at the very least, 
> when a "spare" is installed its label will need to be updated to match 
> its function. We also have several lengths of cables of RG-58, 
> although the RG-59 cables are all 55'. It might make sense for the 
> RG-58 cables to simply order uncut cable,  connectors and labels that 
> can be installed as required. That allows the additional cable to be 
> used for any need that arises (including ones/twos connections that 
> are not on the list). For the RG-59 one could order spares of the 55' 
> length, but uncut rolls again provides flexibility.

Yes, we will use quality labels also for the replacement cables. I am 
adding 10 or so spare cables for each of the different types of cable 
assemblies at this time. For future needs, I agree that we should buy 
bulk cable and the corresponding connectors. There are minimum order 
requirements for cables (spools of 100', 500' 1000') but all the cables 
and connectors are available commercially (COTS).
> 4. RG-59 type cable. Belden 8281F does not have a fire rating in my 
> catalog (is it CL2?) This particular cable also has a fairly large 
> diameter (0.305"), so the SHV connector will of course need to match it.

I had this cable as a place holder and it is not CL2 rated as you 
correctly point out. The cable to be used, and the only one, is Alpha 
Wire 9059C which is CL2 rated and has a diameter of 0.242".
> 5. Quantities of Bcal and Fcal cables are correct.
> 5a. There are no HV cables for Bcal, but what about the required LV 
> cables? Will they be purchased from another list? (We do not want them 
> to fall between the cracks).

The BCAL will have LV cable assemblies for the preamp/sum electronics 
and cable assemblies for the BIAS. These are multi-conductor cable 
assemblies with different connectors and will be on a separate 
procurement. I am also working on the final specifications for these.

> 6. I would like Chuck (or designate) to review all the dimensions in 
> the tables once again and check that nothing has changed. For example, 
> it may be that the detailed design of the Bcal readout may have some 
> effect on the actual lengths. (The lengths were of course determined 
> long before we have detailed the geometry of the Bcal readout). There 
> may have changes to the geometry for other systems as well.

Chuck and Tim checked the lengths a few times at my request over the 
past few months (I don't think they want to hear from me again on this 
subject ;) but I also don't think I am persona non grata). I agree this 
would be the right time for a final check.

Thanks and best regards,
Fernando

>
> Cheers, Elton.
> Elton Smith
> Jefferson Lab MS 12H5
> 12000 Jefferson Ave
> Suite #16
> Newport News, VA 23606
> (757) 269-7625
> (757) 269-6331 fax 
>
> On 5/23/11 11:04 PM, Fernando J. Barbosa wrote:
>> Dear colleagues,
>>
>> We have already reviewed the cable specs over a year ago. As I am 
>> starting procurement of all these cables, I find it opportune to ask 
>> you to perform a final check.
>>
>> I have attached a file that shows the cable lengths (actual), 
>> connectors at each end and quantities for each detector subsystem. 
>> Please let me know if there are any discrepancies before I submit the 
>> PR by the end of this week.
>>
>> The procurements for the items in green are complete and the cables 
>> for the collimator are not defined at this time and will be procured 
>> at a later date.
>>
>> Thanks in advance and best regards,
>> Fernando
>>
>>
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>> Halld-jlab at jlab.org
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