between the conductor and the dewar conductor 11 connects to harness 22 which in turn connects to inner cryogen vessel 23 conductor 11 is held inside outer rigid tube 14 by third fourth and fifth low thermal conductivity pins 19 20 and 21 see fig4 inner cryogen vessel 23 is insulated by evacuating the volume between it and outer vessel 24 harness 22 comprises a number of thin high thermal conductivity copper ribbons joined at the middle and each end conductor 11 connects to the middle join the harness loops circumferentially around inner cryogen vessel 23 about 2 3 of the way bretween the middle join and each end join the harness is folded over on itself to create a 90 u00b0 bend and is then connected to the top of inner cryogen vessel 23 this moves the 34 hot spots 34 created at the join above the level of the cryogen thereby preventing localized boiling and reducing vibration without significantly affecting t min however if the holder is tilted it is still possible that the cryogen will contact the 34 hot spots 34 this problem is minimized see fig5 by connecting harness 22 to ring 30 which in turn connects at brazing points 31 to a diameter of inner cryogen vessel 23 the diameter being parallel with the long axis of conductor 11 normally the main tilt axis of the holder in this variation even with the dewar filled with cryogen and at relatively high tilt angles the cryogen will not contact the 34 hot spots 34 in a previous known design there is no 90 u00b0 bend in harness 22 and the end joins were attached to the sides of inner cryogen vessel 23 the present invention ensures good thermal conductivity and provides significantly increased flexibility particularly at.