
Removing and Installing the MPMS Sample Tube
Quantum Design MPMS Service Note 1014-305, Rev. C-1 3
October 20, 2005
4. Grip the sample-tube assembly by the brass block, then remove it from the probe. You
might need to turn the sample-tube assembly slightly as you raise it out of the tube. Keep
the sample tube straight and take care not to bend or break the fragile wiring along its
sides.
II. Installing the Sample Tube
II.A Insert the Replacement Sample-Tube Assembly
Important: When you insert the replacement sample-tube assembly, take extreme care with
the wiring that runs down the outside of the sample tube—the wiring is fragile and easy to
break. Also, you must keep the sample tube straight (it bends easily).
1. Examine the O-rings that are referred to in Step I.F (L and P, Figure 2) to determine if
they are clean and well coated with Apiezon M grease. Clean and grease them if
necessary, then put them back in place.
2. Grip the new sample-tube assembly by the brass block and slowly insert it into the
vacuum-sleeve assembly (Q, Figure 2). You might need to turn the tube slightly as you
lower it so that it will fit. Keep the sample tube straight, and take care with the fragile
wiring along the outside of the sample tube.
3. The block of the sample-tube assembly should now be seated on the vacuum-sleeve
assembly.
4. Reattach the cable assembly (O, Figure 2) to the connector (N, Figure 2) on the sample-
tube assembly (M, Figure 2). Note that the brown wire connects to pin number 1 and is
aligned with the arrow on the connector socket of the sample-tube assembly.
5. Move back the airlock-valve assembly (I, Figure 2) until it is properly seated on the
sample-tube assembly.
II.B Reinstall the Top Plate
1. Seat the top plate (F, Figure 2) onto the airlock-valve assembly, aligning the screw holes.
2. Insert the four 1/4-20 cap screws (E, Figure 2) into the holes in the top of the top plate,
but do not tighten them yet.
3. Insert the two 6-32 button head screws (G, Figure 2) into the holes in the back of the top
plate, but do not tighten them yet.
II.C Reinstall the Head-Cover Assembly
1. Reattach the leads (K, Figure 2) to the J1, J2, and J3 electrical connectors (A, Figure 2)
inside the head-cover assembly (D, Figure 2).
• mixed-color wires connect to J1
• brown wires connect to J2
• black wires connect to J3
2. Fit the head-cover assembly around the airlock-valve assembly, the sample-tube
assembly, and the vacuum-sleeve assembly, matching the thru holes on the head-cover
assembly with those on the top plate (H, Figure 2) and under the vacuum-sleeve
assembly (R, Figure 2).
3. Insert the eight 4-40 screws (C, Figure 2) into the thru holes in the head-cover assembly,
but do not tighten them yet.
4. Simultaneously tighten the screws located at C, E, and G (Figure 2) on the head-cover
assembly and the top-plate.