1. The basic thermal components: the CCR assembly
CCRs in contact only with KEL-F plastic. Good thermal isolation to avoid:
Mechanical deformations
High thermal gradients
Both the above would alter the CCR optical response to lasers
Al retainer rings also isolated (in contact only with plastic rings)
CCR BACK located in a closed Al cavity
Al retainer ring
KEL-F ring
Fused silica CCR
Al screw
Just finished building the 3x3 matrix to measure the CCR and retainer ring THERMAL RELAXATION TIME
September 2005

2. Status of thermal studies
Characterization of the thermal behavior of the single CCR
Thermal relaxation time, tCCR, in space climate:
FIRST simulation results on the LNF climatic facility with SINDA-Fluint
(no measurement ever; values in the literature range from ~2000 sec to ~7000 sec)
Asymptotic temperature, T(∞): FIRST simu. results
Simulation results on tRETAINER RING in progress
Hardware:
3x3 CCR matrix prototype: READY
Plastic rings: KEL-F purchased
now exercising machining with DELRIN, available in house
Cryostat: special flange for GE window for IR camera: READY
Urgently needed: solar simulator and Ge window for measuring temperatures with IR camera
September 2005

3. Simulation work in progress According to IC’s note, tCCR is unknown at the level of 250%. This implicates a 1-2 % error on the node for the Lense-Thirring effect. If we measure tCCR at 5% level this will give % error of the node for LT. With a ≤ 0.5 K accuracy on thermometry this is within (statistical) reach
SUN=on, IR=off
Error on T = 0.5 K
T (K) of CCR
Time (sec)
SUN=off, IR=on
Error on T = 0.5 K

7. Completed hardware work
LAGEOS CCR
With plastic rings
Cryostat ready.
Special flange
for Ge window
in place
Al CCR
matrix

8. Solar simulator configuration: top view
LARES:
d = 30 cm
Simulator
d = 25 cm
CCR matrix:
~ 15 cm
~ 0.9 m
q~15o
Cooler
IR camera
Thermometry measurements with
< few % accuracy
Very good IR camera; temper.
accuracy 0.1oC in [-100o,+100o]C
In addition to IR camera will also
use discrete temp. sensors with
better accuracy in a much larger
temp. range
September 2005