1. Cryogenics to cool UCT @ 0.1 K
CERN co-worker:
Thomas Eisel (lecturer)
Diego Perini
Friedrich Haug
Tapio Niinikoski
T. Eisel

2. Outline Presentation Radiation to UCT
Adhesion test of black paints
Heat transfer UCT – MC of DR (2 possibilities)
Next steps
T. Eisel

3. Radiation to Ultra cold trap
regions of experiment:
1 e+ accumulation
2 catching
3 instrumentation
4 combination
5 measurement
T. Eisel

4. Adhesion test black paints
Black paints used as coating for radiation shields (absorb photon’s energy)
Comparison of Aquadag (Dag 502 used CERN cryolab) and MH2200 Solar Absorber Coating (Alion, povide coatings for space applications).
OFHC, Surface treatment
Chemical degreased & chemical increase of roughness)
Painting and baking
brushed on both sides
DAG 502 layers of 10 microns possible; MH microns, baked
Thermal Cycling
thermal cycling between ambient temperature and 77 K.
20 thermal cycles will be performed.
Done !
T. Eisel

5. Adhesion test black paints
For comparison the adhesion test after the thermal cycles.
Coatings will be scratched with a sharp tool (cross-cut test, referring ISO 2409).
The off flaking particles will be afterwards removed from the surface with a scotch tape.
Amount will be compared.
To Do !
T. Eisel

6. Heat loads to UCT/MC
Thermal radiation (warm to cold surfaces) ~ 1 mW
Residual gas ~ 1 mW
Thermal conduction (construction material, wires)
Electrical dissipation (sensors)
Other heat dissiption (laser, annihilation, ...)
Heat load -> has to be transferred into the Mixing Chamber !!!
Drawback: different potential of 5 Electrodes
2 possibilities?
T. Eisel

7. Sandwich Results of measurements @ 5 K extrapolated:
@5 K without Kapitza Resistance between He Dilution and Copper plate
<3.5 mW (small budget, 2 mW due to radiation, residual gas)
has to be measured under real conditions
T. Eisel

8. Rod
Electrical Insulation with Al2O3, heat transfer in copper
T. Eisel

9. Rod - first try
Magnetic permeability could be room temperature -> effect was visible
(Ni/Fe = 1/7)
better measurements at low temperatures necessary (not possible at CERN)
Besides, difficult to estimate the impact
T. Eisel

10. Rod - status Production of parts done for:
Test active brazing with AgCu betw. Al2O3 and Cu (OFHC)
Test electron beam welding to the MC lid out of CuBe
incl. metallographic cut
T. Eisel

11. Next steps Test of coatings (cross-cut test)
Test of brazing & electron beam welding
Test leak tightness with super fluid 4He
Production of Test MC with 1 rod
Test MC with Indium seal
Braced and welded connections
Measurements of thermal behaviour
for both: Sandwich & rod
@ final Temperatures of K
Production of new MC, solenoid to destroy the superconductivity of In (of sandwich)
Implementation in DR, instrumentation
Measurement of Kapitza Resistance, Heat conduction, Heat transfer coefficients...
T. Eisel