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Beamline U9B

General Information

Source Type
Bending Magnet

Status
Operational

General User Beamtime
75%

Energy Range Category
Ultraviolet

Energy Range
0.8 - 8.0 eV

Beamline Type
Participating Research Team (PRT)

Technique(s)
Time-resolved spectroscopy
Ultra violet circular dichroism
Ultraviolet florescence spectroscopy

Institution(s)
Brookhaven National Laboratory, Biology Dept.

Research Types
Studies of the solution structure and dynamics of biological macromolecules such as DNA, RNA, proteins and polysaccharides. Circular Dichroism and Fluorescence spectroscopy

Contact Information

Spokesperson The person from each beamline who acts as a contact point between the beamline management and NSLS administration. Contact for questions about the beamline scientific program, experimental capabilities, and beamline management.
John Sutherland, Brookhaven National Laboratory, jcs@bnl.gov, 344-3279

Local Contact The beamline staff member who is typically responsible for overseeing the daily operation and maintenance of the beamline. Contact for questions about beamline instrumentation, experimental details, and training.
John Trunk, Brookhaven National Laboratory, trunk@bnl.gov, 344-3406

Beamtime Scheduler The beamline staff member responsible for coordination of beamline schedule every trimester. Contact for questions about beamtime scheduling.
John Trunk, Brookhaven National Laboratory, trunk@bnl.gov, 344-3406

Beamline Phone
631-344-5509

Instrumentation

Beamline Characteristics

Energy Range Mono Crystal or Grating Resolution (ΔE/E) Flux Spot Size (mm) Total Angular Acceptance (mrad)
140 – 600 nm (8.9 – 2.1 eV) Vacuum 1.67 nm/mm   2 mm diameter 37H x 10V
185 – 900 nm (6.7 – 1.4 eV) Air (Nitrogen Purge) 1.8 nm/mm   2 mm diameter 37H x 10V

Source Type
Bending magnet

Optical System
Mirror #1: Copper planar mirror coated with electroless nickel, overcoated with gold; not adjustable; at normal incidence angle; deflects beam 90 degrees down from horizontal; located 2.5 meters from the source.

Mirror #2: Pyrex off-axis ellipsoid mirror coated with aluminum, over coated with magnesium fluoride; reflects the beam horizontally, perpendicular to the original beam, thereby erecting it. Predominant polarization is vertical; at normal incidence angle; steerable via remote controls; focal point at entrance slits of monochromators; located 2.7 meters from the source.

Experimental Apparatus
Vacuum Excitation:

Vacuum Spectrometer: One-half meter Czerney-Turner single grating vacuum monochromator dedicated to vacuum spectrometer; operates at high vacuum [10-7 Torr] and separated from UHV by calcium floride window; 1200 grooves/mm holographic quartz grating coated by aluminum, over coated by magnesium floride; 0 - 3 mm independent entrance and exit slits; located 3.9 meters from the source.

Fluorescence Spectroscopy (steady state and time-resolved): 220 mm single torodial grating emission vacuum monochromator; thermostated sample holder from -10 degrees to 90 degrees C; cryostat from -172 degrees to 20 degrees C; and a cryogenic refrigerator system for temperatures down to 12 K.

Circular Dichroism and Absorption Spectroscopy: A calcium fluoride photoelastic modulator, vacuum in sample chamber to 0.001 Torr, sample thermal control from -10 degrees to 90 degrees C.

Air Excitation:

Air Spectrometer (purged with dry N2): 227 mm focal length double grating spectrometer; wavelength range (220 - 1000 nm); 0 – 2 mm entrance and exit slits.

Simultaneous Time-Resolved Fluorescence (Omnilyzer): Position sensitive photomultiplier for simultaneous measurement of time-resolved fluorescence and polarization across emission spectrum.

Computer System Hardware & Software
Pentium III Industrial PC with ~8 PCI slots running Microsoft Windows for beamline control and data collection. Remote Linux data storage server with dual Pentium processors and many-GigaByte hard drives; Canberra single board MCA dedicated to time resolved fluorescence and MPA to collect F(t,lambda) data from position sensitive photomultiplier.

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