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HI J,
do modern synchrotrons overcome the increase of thermal motion with
increasing temperature? Isn't this the main reason data are better
when collected at low temperature? Radiation damage is one reason for
sure, but not really the main reason. ;-)
Tim
On 02/06/2014 12:50 PM, James Foadi wrote:
> Dear Enrico,
>
> "almost always it will be possible to achieve better diffraction
> using cryogenic data collection."
>
> I would say "almost always until now". Times change,
> instrumentation improves and data collection techniques are
> becoming cunning. It's right time people start exploring the new
> possibilities offered by modern synchrotrons.
>
> All the best,
>
> J
>
>
> Dr James Foadi PhD Membrane Protein Laboratory Diamond Light Source
> Ltd. Diamond House Harwell Science and Innovation Campus Didcot
> Oxfordshire OX11 0DE United Kingdom
>
>
> office email: [log in to unmask] alternative email:
> [log in to unmask]
>
>
> personal web page: http://www.jfoadi.me.uk
>
>
>
> On Thursday, 6 February 2014, 11:35, Enrico Stura <[log in to unmask]>
> wrote:
>
> Dear Joern and other BBers,
>
> While I fully agree that it is important to test a few images at
> room temperature, to know the crystal's potential, I think that
> almost always it will be possible to achieve better diffraction
> using cryogenic data collection. Those rare cases, as the one you
> mention below are worthy of critical investigation as to why there
> is a loss of order on cryo-cooling: Unsuitable cryoprotectant is my
> first guess. The rate of cooling in liquid N2 is slow, liquid
> ethane could be a better choice.
>
> Enrico
>
>
> On Thu, 06 Feb 2014 11:19:47 +0100, Joern Krausze
> <[log in to unmask]> wrote:
>
>> Dear Theresa,
>>
>> We recently collected a room temperature data set from one single
>> crystal at Petra III. The beam line was equipped with a Pilatus
>> detector. Data were good to 2.7 A. In contrast, at 100 K similar
>> crystals diffracted very poorly. So, it is perfectly possible to
>> obtain useful room temperature data sets from synchrotron
>> sources. I have to admit that in our case it certainly helped
>> that the crystal belonged to a high-symmetry space and full
>> completeness was achieved after 40 degrees angular range.
>>
>> Regards,
>>
>> Joern
>>
>> Sent from my iPad
>>
>>> On 06.02.2014, at 10:51, Theresa Hsu <[log in to unmask]>
>>> wrote:
>>>
>>> Dear crystallographers
>>>
>>> Just out of curiosity, is it possible to collect datasets from
>>> crystals at room temperature at synchrotron? Are fast detectors
>>> like Pilatus useful for this?
>>>
>>> Thank you.
>>>
>>> Theresa
>
>
- --
- --
Dr Tim Gruene
Institut fuer anorganische Chemie
Tammannstr. 4
D-37077 Goettingen
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