Extended Arc Goniometer Head
With Detachable Arc Assembly

These highly specialized goniometer heads are designed specifically for vertical spindle geometry such as found on the R-Axis or MARR detectors.  With the magnetic mounting system"> Extended Arc Goniometer Head With Detachable Arc Assembly These highly specialized goniometer heads are designed specifically for vertical spindle geometry such as found on the R-Axis or MARR detectors.  With the magnetic mounting system, the user can rapidly  transfer frozen crystals onto or off the x-ray instrument.  The extended arc can then provide up to140° of rotational freedom about one axis to help achieve the desired crystal orientation, often a difficult procedure with frozen crystals.  Rotating the crystal above the arc does not translate it when appropriately sized mounts are used, so the crystal remains in the cold stream.  A square socket adjusting wrench for the stainless steel x-y translation is provided. Alternatively, the extended arc can be detached at the 45° position after the crystal has been placed on the goniometer and the arc repositioned.  This feature thus allows full rotation about the spindle even in configurations with tight space restrictions.  Samples mounted in loops tend to dehydrate rapidly due to the large surface area of the liquid film holding the suspended crystal.  The magnetic mounting system is a convenient method for very rapidly attaching the crystal to the goniometer.  The sample holder with a fiber loop affixed becomes one small unit that is held directly to capture the crystal from one small drop of harvest buffer.  The ferromagnetic base of the sample holder then allows the crystals to be placed on the goniometer in one motion.   Another advantage to this method is that it allows an equally rapid transfer of the crystal from the goniometer head.  The frozen crystal can be immersed into a tube containing liquid nitrogen, removed from the goniometer, and stored in standard cryogenic storage dewars.  The sample can be re-mounted by reversing this operation.  This is particularly useful for freezing and pre-screening crystals that are then transported to synchrotron radiation facilities for data collection. Catalog Number 480              48mm height to center of arc (use with R-Axis etc.) 480-7043     as above, set-up with Hampton magnet 481               67mm height to center of arc (use with MARR etc.) 481-7043     as above, set-up with Hampton magnet                                                                                                  Accessories 485                 pkg of 50 magnetic mount caps to hold 1/8" #1601B pins 486                 pkg of 50 magnetic mount caps to hold wire loops 1601B            pkg of 50 1/8" brass specimen mount pins  DR-01          Cryo-Loop Kit (make your own loops) Instruments and Supplies for X-Ray Crystallography since 1941