Since Frank mentioned cryotongs, I wanted to point to a video of their use
on youtube:
http://www.youtube.com/watch?v=ikiF2qpCRKs
Jim
On Wed, 8 Jun 2011, Frank von Delft wrote:
Hi Zhijie --
With all manipulations on the goniometer, I strongly advise what I learnt
from Elspeth Garman: practice, practice, practice... but not with your real
crystal! Take it down, put up a dummy pin, and take the time play around. I
imagine even a non-hollow pin can be bent without throwing it off with
sufficient practice -- though Weikai is right, with those pins it'll be
REALLY tough, the special Hampton pins are much recommended, because they
have a weak point, making them far easier to bend. A little tool is also
supplied.
I do not agree however that you need a beamline with Kappa -- indeed, if you
were at such a beamline, there would be no need to bend the loop! (How often
I've wished for it...) The un-bent loops fit perfectly well into cryotongs,
as long as you affix them to the base at the right length; once bent, the
pins may not fit anymore, but you can always straighten them again before
retrieving them.
Of course, if you've already harvested your crystal on a non-bendable pin,
this doesn't help; but we routinely bend the loop itself, by pushing on the
stem of the loop (close to where it attaches to the pin), with a pipette tip
cut into a sharp point simply with scissors (you want something non-metal, so
as not to conduct heat onto the sample.) It's not exact, of course, and
(again) takes some practice. But very effective -- it's rescued umpteen
datasets for us. But BEWARE: DO NOT BREATHE WHILE DOING THIS! (Go figure.)
HTH
phx
On 07/06/2011 23:33, Li, Weikai wrote:
Hi Zhijie,
This loop is good if you have a long unit cell on one dimension and you can
align your crystal in a particular direction. You basically need a
beamline equipped with Kappa, which allows you to directly put the crystal
on with the plastic tube. A normal cryotong does not hold the bent loop.
Regards,
Weikai
________________________________________
From: CCP4 bulletin board [[email protected]] On Behalf Of Zhijie Li
[[email protected]]
Sent: Tuesday, June 07, 2011 5:30 PM
To: [email protected]
Subject: [ccp4bb] Hampton's adjustable cryoloop
Hello,
I just noticed that Hampton Research carries this adjustable mounted
cryoloop (HR5-900):
http://hamptonresearch.com/product_detail.aspx?cid=24&sid=136&pid=385<wlmailhtml:{35C92305-260C-4820-B40D-05B0D91A0A8F}mid://00000065/!x-usc:http://hamptonresearch.com/product_detail.aspx?cid=24&sid=136&pid=385>
This looks quite interesting to me, as it seems that not every synchrotron
station's configuration can allow the use of an extended arc.
I wonder if somebody here can share some insights or experiences about this
adjustable cryoloop. I once tried to bend my non-hollow stainless steel pin
in liquid nitrogen with tweezers. It didn't work - the pin was too stiff
then I lost my crystal in the end. I wonder if this cryoloop was designed
such that bending it would be easier.
Thanks in advance!
Zhijie
