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USJ-TAX  -  US-Japan Triple Axis Spectrometer

Expected Performance

The USJ-TAX is a conventional triple-axis spectrometer with variable incident energy and variable monochromator-sample and sample-analyzer distances. The cold guide 4 bender and guide hall shielding reduce the background levels at CG-4C, and the 15-cm tall guide profile is well exploited by CG-4C’s vertically focusing monochromator (PG 002). To enhance accommodation of strong magnetic fields at the sample position and to simplify future polarization analysis, the amount of ferromagnetic material has been minimized in the construction of this instrument.

This new Cold Neutron TAX will be world class with high flux at sample, and a design compatible with polarized neutrons and the BNL 11 T vertical bore sample magnet. Future upgrades include Polarized Neutrons, and a possible multi-blade analyzer / position-sensitive detector assembly.

This new Cold Neutron TAX will be world class with high flux at sample, and a design compatible with polarized neutrons and the BNL 11 T vertical bore sample magnet. Future upgrades include Polarized Neutrons, and a possible multi-blade analyzer / position-sensitive detector assembly.

The USJ-TAX will be well integrated into the HFIR user program. The instrument will employ the data acquisition software system known as SPICE, first developed for HFIR TAX’s and now used on a variety of instruments worldwide. Its sample table can accommodate all sample environments currently available at HFIR.

 

Instrument Details

  

Beam Spectrum

Liquid Hydrogen Moderator

Monochromator Range

Vertically Focusing PG (002)
35o < 2qM < 145o

2 Å < lM < 6.4 Å
2 meV < Ei < 20 meV

Sample Scatter Range

-170o < 2qS < 170o

Variable arm lengths
Location-dependent

Analyzer Range

PG (002)
-107o < 2qA < 107o

lA < 5.4 Å, Ef > 2.8 meV
Location-dependent

Collimation (FWHM)

a1 open (20’ @ 2 Å, 40’ @ 6.4 Å)
a2 80’, 40’, 20’, 10’
a3 80’, 40’, 20’, 10’
a4 80’, 40’, 20’, 10’

Before Monochromator
Monochromator-Sample
Sample-Analyzer
Analyzer-Detector

Beam Size

25 mm x 15 mm at sample

Vertically focused

Filters

Cooled Beryllium
PG

CG-4 bender removes most higher order

Flux at sample

3E7 n/s/cm2 at 3 Å (est.)

Detector

3He

Polarization

Polarizing supermirrors, Transmission (not yet)

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Last Modified: Tuesday, 04-Mar-2008 14:57:22 EST
Please forward all questions about this site to: Barry Winn

 


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