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Heating Shield

General Information

The heating shield is installed on the goniometer head between the sample and the phi axis. It protects the phi axis from over cooling and ice formation. The heating shield has a cone shape for reduction of turbulence and contains a thermocouple which is used to regulate the temperature. The Heating Shield in Assembly

Replacing the Shield

Loosening the Screw in the Goniometer Head If the heating shield becomes covered with ice, you may need to install the replacement heating shield which is located on the tool board. First loosen the tiny screw on the goniometer head, which may be accessed through a small hole in the heat shield as shown below. Then you can remove the shaft from the goniometer head. Remember to tighten the screw when finished installing both washers.

In order for the heating shield to rotate freely, a washer must be installed on both sides of the bearing. The washers should be installed so that the thinner side of the washer is pushing on the inner radius of the bearing.

A WasherWasher on the shaft

Heating Shield Design

The heating shield has a cone shaped body with a heating element attached to it from the inner side. A ball bearing is installed in the top of the cone. This bearing facilitates shield rotation on the goniometer head shaft. A thermocouple is attached to the side wall of the shield. The reading from the thermocouple is used to keep the shield temperature approximately the same independent of the presence and the strength of the cryo-stream. The wire leads to the thermocouple and the heating element pass through the side wall of the shield.

The latest design revision includes replacement of the nichrome wire heating element with a printed-circuit heating element on a flexible capton-aluminum substrate and additional protection of the wire leads with an aluminum wire guide tube attached to the side wall of the shield. See Assembly Diagram for details.

Complete part list for the heating shield includes:

  1. Heating Shield Body. Drawing. 
  2. Wire Guide. Drawing.
  3. Heating element. Drawing. Producer: MINCO Products, Inc. p: 763-571-3121, f: 763-586-2988. Part #: HK22765. SLAC PO.#: 18148.
  4. Ball Bearing. Part #: A 7Y 5MFSS1006. Producer: Sterling Instrument. p: 516-383-3300. f: 516-326-8827. Supplier: Western Components, p: 650-594-1222.
  5. Thermocouple copper/constantan, teflon ins. Part #: 5TC-TT-T-30-72. Diam: 0.01". Producer: Omega Engineering, Inc. p: 203-359-7874, f: 203-359-7700.
  6. 4-pin connector, metal, male plug, circular, Trim-Trio system. Part #: G6B104PNE. SLAC store cat.# 59-299-206-01, item # 046400.
  7. 4 Pin Contacts, solid, machined, size 16. Trim-Trio system. Part # RM24M-9D28. SLAC store cat.# 59-299-801-12, item # 048500.
  8. Heat shrinking tube, 1/4" dia.
  9. Thermoconductive compound ECCOBOND 285 and Catalyst 9 (curing agent). Producer: Emerson & Cuming, Inc. Supplier: E.V.Roberts. Tel: (800) 374-3872 - Ext.1 Fax: (310) 839-9427

For further information see Heat Shield Assembly - Illustrated Guide.