1. HPR activities at INFN Milan
Open Questions
How to qualify an HPR systems?
How to compare different systems?
Pressure
Throughput
Linear Speed
Distance
Number of nozzles …
Transportable system for measure parameters in the HPR systems: jet force, jet profile and water jet effects
Paolo Michelato, TTCM - LNF December 5-7, 2005

2. Possible strategy for HPR process study
Measurement of
Force and profile
HPR effect on Nb
Correlations?
Cleaning
Niobium oxidation
HPR process
optimization
? “easy”
to be measured
quantity
Paolo Michelato, TTCM - LNF December 5-7, 2005

3. Diagnostics Diagnostics with load cell:
Force measurement
Profile measurement
Measurements on wedged targets
Diagnostics using Nb sample oxidation …
Paolo Michelato, TTCM - LNF December 5-7, 2005

4. Hardware
Nozzles: HP pump: Kärcher HD 600 C, 10 liters/min, pmax 120 bar
Nozzle: 0.55 mm, sapphire diaphragm, Spraying System VS120
Load cell TEDEA HUNTLEIGH mod. 505H-2M-2 max load 2kg, resolution 1 g.
Paolo Michelato, TTCM - LNF December 5-7, 2005

5. Water Jet force vs. pump pressure
Nozzle with
sapphire orifice
Nozzles
Target
Water jet
Target
Shield
Load
cell
Load
cell
Pressure regulator
From Bernoulli’s law the expected force is 3.9 N
Paolo Michelato, TTCM - LNF December 5-7, 2005

6. Water Jet force and profile characterization
Momentum
and energy
transfer
Pass through beam
Force
“erf” like
behaviour
F, s
Intercepted beam
Displacement
Measured
Force
Displacement
vertical speed: 2.2 mm/min
F = 3.5 N
F = 3.5 N
s = 0.82 mm
From Bernoulli’s law the expected force is 3.9 N
s = 0.82 mm
Displacement
Water Jet structure
Paolo Michelato, TTCM - LNF December 5-7, 2005

7. Jet profiling
If we approximate the jet radial dependence with a Gaussian profile, from the information of the behavior of the force vs. displacement on the target borders, we can extimate the spot dimension applying
F0 is the total force and s is the spot size. The jet parameters are calculated fitting F(z) to the experimental values.
Paolo Michelato, TTCM - LNF December 5-7, 2005

8. Spot size (s) vs. distance
Nozzle head
position
Spot size evolution with respect to the radial position from the head axis. The nozzle exit is at 17.5 mm from the head axis.
Paolo Michelato, TTCM - LNF December 5-7, 2005

9. Water Jet spot size vs. pump pressure
Paolo Michelato, TTCM - LNF December 5-7, 2005

10. Water jet interaction on a not perpendicularly surface: force measurement
Nozzle with
sapphire orifice
Measured Force up
down
Water jet 2q
30°, 45°, 60°
Load
cell
Load cell “transversal load” rejection:
Is good: about 95 %. Residual is 5%.
(5g over 100g). Calibration done in a separated set-up.
Paolo Michelato, TTCM - LNF December 5-7, 2005

11. Water Jet force vs. angle
d = 17 mm
d = 87 mm
“Sin” dependance of the force vs. target angle
d = 51 mm
d: distance nozzle - cell
Paolo Michelato, TTCM - LNF December 5-7, 2005

12. Water Jet spot size dependence vs. target angle
d = 87 mm
d = 51 mm
The measurements confirm the “sin” dependence both of force and spot size from the angle. This is important once the cleaning effect on the curved cavity surfaces will be studied.
Paolo Michelato, TTCM - LNF December 5-7, 2005

13. Water jet power estimation
Using the data measured, we can estimate the power of the water jet on the cavity surface.
The 190 Watt mean power of each of our jet corresponds, in the Gaussian approximation, to a peak power density of 250 Watt/mm2 at 35 mm from the head axis (17 mm nozzle to surface distance)
Paolo Michelato, TTCM - LNF December 5-7, 2005

14. Static water pressure on the cavity during HPR
Static water pressure distribution on the cavity wall along the axis for a TESLA cavity using the jet dependences discussed before.
Paolo Michelato, TTCM - LNF December 5-7, 2005

15. Nb oxidation as a water get profile tester
Different shapes of the water jet effect on Nb samples. Left image was taken at 17 mm from the nozzle, right one at 87 mm from the nozzle. The annular footprint disappear at longer distance.
Paolo Michelato, TTCM - LNF December 5-7, 2005

16. Nb sample oxidation: sensor? linear ?
1 mm
Nb oxide thickness increase
Paolo Michelato, TTCM - LNF December 5-7, 2005

17. Monochromatic light can help to count fringes
1 mm
1 mm
1 mm
1 mm
l = 488 nm
p=100 bar, s=0.345 mm
l = 532 nm
Paolo Michelato, TTCM - LNF December 5-7, 2005

18. From static to dynamic HP exposition
p=100 bar, s=0.345 mm
10 s
15 s
20 s
0.085 mm/s
1 mm
To evaluate the energy deposited by the water jet on the samples, we have performed different measurements on Nb samples up to visible changes of the surface color. In the gaussian model, the energy deposited by a fixed water jet with spot size s0 impinging for a time t on a sample is equivalent to the one deposited by a moving jet at speed v
10 s of static exposition should correspond to mm/s
Paolo Michelato, TTCM - LNF December 5-7, 2005

19. Coloured part is oxidized?
O2 is increased
Nb is decreased
F is decreased
Paolo Michelato, TTCM - LNF December 5-7, 2005

20. Water Jet force and profile characterization old and new load cell set-up
Easy exchangeable
targets
Old
New
Guidance for alignement
Paolo Michelato, TTCM - LNF December 5-7, 2005

21. “Long” time exposition to HPR
100 bar, 17 mm nozzle-to-sample distance
20 mm
10 min
20 mm
3 mm
20 mm
3 mm
30 min
20 mm
200 mm
Paolo Michelato, TTCM - LNF December 5-7, 2005

22. Strategy for HPR process optimization
Measurement of
Force and profile
HPR effect on Nb
Long time exp.
Short time exp.
Correlations ?
Cleaning
Niobium oxidation
HPR process
optimization
? “easy”
to be measured
quantity
The force is a correct variable to be used?
Oxidation can be correlated with the cleaning effect?
Paolo Michelato, TTCM - LNF December 5-7, 2005

23. The end
Paolo Michelato, TTCM - LNF December 5-7, 2005

24. Distance nozzle - sensor:
Very preliminary data
Distance nozzle - sensor:
TTF Equator
Data are calculated as the water will loose all the energy in the impact and no energy was loss during the flight from the nozzle
Paolo Michelato, TTCM - LNF December 5-7, 2005