Rules for BT-1 Operation

Information board and log book.

You MUST write the sample composition along with your name(s) and telephone number(s) on the white board. Also fill out all information requested in the BT-1 log book and on a BT-1 sample tag.

Shutter/Collimation operation.

This is a two-step procedure. First turn the knob to the desired position, then press enable. Do not turn the knob again until the green locked light comes on. Remove and take the shutter key when working in the beam path.

Monochromator/Collimation selection.

DO NOT CHANGE MONOCHROMATORS. At this time changes are to be made only by Brian, Judy or Qing. Be sure to set the collimation in your buffer if you are not using 15' (this is reset each time you edit the buffer unless A- mode is set).

Sample position.

The beam is 5/8" wide, and is focused to a 2" height at the sample position. To check your sample positioning with a Polaroid camera, close the shutter at the top closed position, place the camera behind the sample, turn the shutter control to the second closed position and press enable. This will rotate the drum through the 7' open position and give a reasonable exposure.

Zero point.

BT-1 does not have encoders, so the zero point should be checked periodically: Remove the beam stop from the X-rail; drive 2theta to zero (d4=0); center the primary beam in detector 1 (fpd 1,4); fit a Gaussian and drive there (y); initialize 2theta to zero (ini4=0). Replace the beam stop.

Scan range, step size, and time.

The default scan range of 3-13 degrees 2theta (1.3-11.3 for Ge311) with a step size of 0.05 is highly recommended so that each data point is counted in two different detectors. Make sure you have at least 4 prefactors. W+ produces a log file.

Sample checking.

If you are unsure of the quality of your sample, run a quick scan (15' collimation, range 5-10 degrees, 0.1 degree steps, 10 sec count).

ICP and data files.

Do not create files in someone else's subdirectory (especially mine). Exit ICP and use SET DEF [BT1.xxx], or log off and then restart.

Sample changer.

Do not attempt to mount the 6-position automatic sample changer without instruction/approval of Brian, Qing or Judy. The ICP command next advances to the next sample position.

Unloading Samples.

Survey your sample before removing it from the instrument. All V sample cans are to be stored in the BT-1 cabinet when not in use. Log sample cans to be removed from the BT-1 area. Never open cans in C100. At this time, Health Physics must clear irradiated powder samples before they are removed from their cans.

DO NOT ENTER THE DETECTOR AREA WHEN THE BEAM IS ON