[RASMB] Xl-I wavelength check question

[Titus M. Franzmann]

HI, 
I typically use a ultrasound water bath with the slit assembly in ddH2O or
EtOH for 1-5 min. Then air dry. Usually does the job for me.
Best
Titus

-----Ursprüngliche Nachricht-----
Von: rasmb-bounces at server1.bbri.org [mailto:rasmb-bounces at server1.bbri.org]
Im Auftrag von John Philo
Gesendet: Donnerstag, 18. Februar 2010 13:54
An: 'Virgil Schirf'; rasmb at server1.bbri.org
Betreff: Re: [RASMB] Xl-I wavelength check question

Virgil, you are quite right that the slit assembly can cause low intensity
issues, but for the record I believe the physical width of the slit is ~20
microns, not 2 nm! The 2 nm figure one sees in the Beckman manuals refers to
the bandwidth of the light that results after it passes through the slit (as
limited by the long dimension of the slit). 

John

-----Original Message-----
From: rasmb-bounces at rasmb.bbri.org [mailto:rasmb-bounces at rasmb.bbri.org] On
Behalf Of Virgil Schirf
Sent: Thursday, February 18, 2010 9:30 AM
To: rasmb at server1.bbri.org
Subject: Re: [RASMB] Xl-I wavelength check question

Greetings,

After the lamp,  low intensity outputs can be also attributed to dirty slit
assemblies. The slit is 2 nm wide, so it doesn't take much oil or dirt to
partially block this opening. Unfortunately, it is not generally a piece
that can be maintained by a user. The foil the slit is cut into is glued
onto the brass assembly and comes off easily with too much air pressure or
other physical means. There are also two lenses in the assembly with one
flat surface and one convex surface. They can be cleaned and reassembled so
that the two convex surfaces meet to form an hourglass configuration. 

That being said, I would suggest that you have your service engineer clean
or replace the slit if you have a clean lamp and low intensities. 
With the slit out, you can also check the surface of the underlying PMT to
see if oil and dirt have built up on it.

Best regards,

Virgil

Leech, AP wrote:
> Hi everybody,
>
> Some systems, like our XL/I, have an extra window in the monochromator 
> mounting socket, which helps save on lamp cleaning as it keeps the oil 
> from "cracking" on the lamp surface. Our lamp intensity is quite low 
> (~10000), whether this is affected by the extra window I don't know, 
> but it doesn't go down much with use.
>
> It is worth checking this window from time to time - if your AUC has 
> one you should have a special tool for extracting it (like a 
> screwdriver with a round magnetic end).
>
> Best to all,
>
> Andrew
>
>
> Borries Demeler wrote:
>
>>
>> Hi Mark,
>> I should mention that we have to clean our lamps quite regularly, 
>> depending on use perhaps every 2-3 weeks. The procedure is simple 
>> enough, it would be worthwhile to have the service person teach you 
>> how to do it yourself. Sometimes other optical components also 
>> require cleaning, but the lamp is usually the biggest culprit. Lamps 
>> do vary in intensity at 230 nm, most I have come across range between 
>> 12-30 kcounts when cleaned. The UV intensity is lost first, I guess 
>> dirt absorbs in the UV stronger than in the vis.
>>
>> Regards, -Borries
>>
>> _______________________________________________
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>> RASMB at rasmb.bbri.org
>> http://rasmb.bbri.org/cgi-bin/mailman/listinfo/rasmb
>

-- 

Virgil Schirf
Technical Director, Center for Macromolecular Interactions
<http://cmmi.uthscsa.edu> Department of Biochemistry, Rm 4.523U The
University of Texas Health Science Center
7703 Floyd Curl Dr.
San Antonio TX 78229-3900
Voice mail: 210 567-6590
Fax: 210 567-6595
Email: schirfv at biochem.uthscsa.edu <mailto:schirfv at biochem.uthscsa.edu>

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