[esa-t474] 1st DRAFT paper energy resolution

[Alexey Lyapin]

On 03/16/2010 11:21 AM, Michele Viti wrote:
> Matthew Wing wrote:
>>
>> Dear Michele,
>>
>> The results look promising. I have a few semi-detailed comments on a
>> quick read of the paper but state them now as they may require some
>> changes.
>>
>> Cheers,
>> Matthew.
>>
>> o Figure 6. You say that "Not all possible combinations are shown." I
>> wonder why as you show four combinations and there are anyway only six,
>> aren't there ? In this case, I would then show all.
>>
>> o Figure 6, top right. This graph has a particularly strange structure,
>> with a double peak. Do you have any comment ?
>>
>> o Solving Eq.4, I do not get Eq.5. Maybe I have made a mistake, but could
>> you check. E.g. if I take line 1 in Eq.4 and use the values in Eq.5
>> 0.187^2 + 0.018^2, then I definitely won't get 0.1865^2 as in Eq.4.
>>
>> o Fig.9. The dashed line is not y=x, but is offset. Was this just to
>> "best fit" the data, or is there some other reason ?
>>
>> o Fig.11 and its interpretation. Shouldn't the text say, "... vary from a
>> few tenths of mT (for magnet 3B4) up to about 3 mT (for magnets 3B1, 3B2
>> and 3B3)" ?
>>
>> o Section 6.5. ArcTan(-0.4374) is not 23.49 deg.
> Hi Matthew,
> thanks for the comments. I will try to answer.
> 1) To calculate the resolution I needed only four, that's why I didn't
> show all of them.
>
> 2) I saw that double peak structure...but unfortunately I have no
> explanation for that. Probably some calibration constant changed!??! One
> could check direct the I/Q values but I didn't do so far.
>
> 3) I just wrote down in a approximate way the numbers.They should be
> corrected before any publication.
>
> 4) In principle you are right: in general what we need is a relation
> like Y = X + constant. Since we normalize everything at the end, any
> constant does not play any role so I omitted...
>
> 5) In the text I meant the relative difference between magnets. If they
> all would have the same offset, It wouldn't be a problem.
>
> 6) ArcTan(0.4374) = 0.412326504 radians = 23.62 degrees... Sorry I wrote
> a bit wrong:-) Did you mean this?
>
> hope to hear other comments :-)))
>
> Michele** **

Hello All,

A comment on 2). The IQ plot for BPM24 does show two states (see 
attachment), and as Stewart and I learned from ATF work, this means that 
the trigger comes on the edge between two clock cycles and sampling can 
start at two different times with a fixed offset. I guess that 
clustering the points in the IQ space and having two IQ rotation values 
for BPM24 could solve this...

Cheers,
Alex

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