10
c)
Set up the stand approximately in the intended experimental position. Slide the stage
assembly onto the stand and clamp in position using the lever. (See Figure 6 and
Figure 7 below.) Note that the lever can be rotated to any convenient position by
pulling it to disengage the lever from the clamping mechanism.
d)
Lower the sample flow unit dewar leg through the widest hole in the dewar top fitting
to the bottom. (The wide part of the dewar leg is a tight fit through the O-rings in the
top fitting.)
e)
Slide the nozzle of the coldhead through the hole in the holder in the stand and
secure using four caphead screws (supplied) at the base of the nozzle. Use the pre-
existing bend of the flexible section when you arrange the coldhead in position. The
shield tube running down the side of the coldhead must fit in the slot in the side of the
holder. If the shield tube does not line up with the slot, rotate the entire dewar until it
does.
f)
Arrange the nozzle approximately in its intended operating position. After you have
tilted the coldhead to the desired position, clamp the tilt adjuster in place using black
knob. You find it convenient to use the 8 mm Allen key provided at the same time. To
move the bracket assembly up or down the post smoothly, support the weight of the
coldhead by putting your hand under the stage assembly near the coldhead.
g)
Lower the shield unit into the next smaller hole, all the way to the bottom of the
dewar. It is also a tight fit in the O-rings in the top fitting. Connect the fitting on the
top to the fitting on the cold head using the polythene tube supplied. To connect, just
push the polythene tube into the fitting until it stops.
h)
Tighten the three small screws on the dewar top fitting.
i)
Fit a suitable hose from your pressurised supply dewar to the Cryojet dewar. Some
users use polythene tube. This becomes brittle when cold, and must be used with
caution. Other plastics may not be safe, as they may be even more brittle. The fill port
is fitted with a stainless steel coupling, equipped with a flow restrictor. This coupling
has a 3/8” BSP parallel thread, with a 60
°
flare female sealing surface. If necessary,
remove the top part of the coupling. Systems delivered in the USA also have an
adaptor to convert this coupling to a 1/2” flare fitting (unless the system includes a
nitrogen fill hose).
If you have an Oxford Instruments autofill system, see section 8.
If you have an Oxford Instruments nitrogen fill hose, fit it as follows. The brass
adaptor fits onto your pressurised dewar, while the stainless steel adaptor fits onto the
Cryojet dewar. Remove the brass adaptor from the hose, and screw it into the liquid
outlet of your pressurised dewar, using PTFE tape. Screw the hose onto the brass
adaptor using two spanners.
Attach the other end of the nitrogen hose to the dewar top fitting, using the stainless
steel compression fitting that is already fitted to the fill port. Slide the end of the hose
onto the fill port, and tighten the nut securely using two spanners.
