[Comm2011] CCD # 92 -> #93

[Frederic Gonte]

Hi Dietrich,

Simply an error writing the PPRS, I guess it can happen to everybody (error is human no?), especially if detected at night

Sincerely

Frederic

ps: we take account of your proposed secondary analysis

On 12 Sep 2011, at 14:10, Dietrich Baade wrote:

> Dear Konrad, dear All,  
> 
> Three e-mails within a minute confirming the previous mis-identification - so, this ought to be the truth.  Many thanks for the clarification (however:  how was that error possible in the first place?).  
> 
> An important secondary analysis step would it be to check whether the crosstalk patterns between 94, 95, and 96 have changed.  In the past, 93 has seemingly played a fairly minor role in this - but it might still have been a major part of the cause.  
> 
> Best regards,
> 
> Dietrich. 
> ________________________________________
> Von: K Kuijken [kuijken at strw.leidenuniv.nl]
> Gesendet: Montag, 12. September 2011 13:11
> Bis: Olaf Iwert
> Cc: Dietrich Baade; Javier Valenzuela; Nicolas Haddad; Miguel Riquelme; Frederic Yves Joseph Gonte; Christoph Geimer; smieske at eso.org; Gert Finger; mbernard at usm.lmu.de; Sebastian Deiries; OmegaCAM Commissioning 2011 mailinglist
> Betreff: Re: AW: CCD # 92
> 
> Looking at a few images from last night: the problem is in CCD 93, not
> 92. So one of the ones in our troublesome quartet.
> Olaf, we have all the data here - let us know if we can help with any
> analysis.
> Konrad
> 
> 
> Olaf Iwert wrote:
>> Hi Dietrich,
>> 
>> Yes, I already thought about these points yesterday and verified them
>> today.
>> 
>> Before we draw more conclusions we need however more info from Paranal
>> (like you said) and an assessment what works and what does not. At this
>> point it could be caused by almost anything inside the amplifier and
>> video chain: cables, bias voltage, video board......
>> Nevertheless of course it distracts me from thinking normally, as it is
>> not normal and we never saw something similar.
>> When I called yesterday, noone had had time to look at the problem, due
>> to other emergencies.
>> 
>> Some answers to your questions:
>> From all information I have (not much) #92 is the correct number.
>> # 92 did not show any previous problems.
>> In the worst case replacement device could be Chamaeleon, but this
>> device has flatness problems and is also no ideal fit to the channel
>> potential. This is all we have.
>> # 92 is not from a batch, where the protection diodes have been removed.
>> # 92 is not in the mixed voltage group.
>> # 92 is neither inside the group showing crosstalk, nor in the same
>> group where we exchanged the faulty CCD in 2009.
>> All spare devices are on Paranal.
>> 
>> With best wishes
>> Olaf
>> 
> 

Frederic Gonte
Instrumentation Group
ESO Paranal Observatory
Alonso de Córdova 3107 
Vitacura, Casilla 19001 
Santiago de Chile 19 
Chile
e-mail:fgonte at eso.org
Phone:+56 55 43 5248