# Presentation: 389011

## Status of EP at DESY (update)A.Matheisen DESY Hamburg 

- Statistic
- Infrastructure
- Material
- HF Absorber
- Sensors
- Parameter control (T)
- Sulfur
- Q disease
- mysteries

- TTC meeting Frascati Dec. 05   A.Matheisen DESY

## Statistic

- Total EP time (current above 260A): 199 h
- In 2005 >100h
- No of treatments in total :90
- In 2005:  48
- Cavities tested (EP+120 C Bake): 16 since June 05
- Gradients : 8 Cavities >=30MV/m
- 2 showed 35MV/m

- TTC meeting Frascati Dec. 05   A.Matheisen DESY

## Note: Red diamonds = Eacc after 120 C  baking

- Pink square = Q disease ! Result after fast cool down

- TTC meeting Frascati Dec. 05   A.Matheisen DESY

## Slide 4

- TTC meeting Frascati Dec. 05   A.Matheisen DESY

## Slide 5

- TTC meeting Frascati Dec. 05   A.Matheisen DESY

## Cavity performance in respect to average Ep temperature

- TTC meeting Frascati Dec. 05   A.Matheisen DESY

## Infrastructure

- Heat exchange rate too small
- Thermal conductance for H2SO4 to low
- Leak and material not resistant agains 1/9 Mixture
- Material
- PVDF not resistant (depending on molecular structure)
- Shaft seals made from Viton stand for 25h
- Shaft seals made from Teflon > 100h
- HF scrubber
- wet HF gas scrubber failed better once ??  too large
-  home made Teflon tubes (0,8mm wall thickness) heat exchanger
- 	showed HF penetration
- actual HF gas absorber : DESY granular absorbent
- (COSA D) works fine

- TTC meeting Frascati Dec. 05   A.Matheisen DESY

## Vition shaft seal after about 25h of operation

- TTC meeting Frascati Dec. 05   A.Matheisen DESY

## Corrosion on PVDF sump (about 5mm of 10 mm) 

- Corrosion on PVDF sump (about 5mm of 10 mm)

- Welding area

- TTC meeting Frascati Dec. 05   A.Matheisen DESY

## Commercial heat Exchanger 

- Commercial heat Exchanger

- TTC meeting Frascati Dec. 05   A.Matheisen DESY

## HF Absorbent COSA D in commercial cartridge

- Dry absorbent at the point of appearance

- TTC meeting Frascati Dec. 05   A.Matheisen DESY

## 				Sensors

**HF sensors**  commercial sensor's applied at DESY
- 	calibration  2 times a year by official service
- It was found that aging is faster than that period
- 	-In the DESY EP Set up.

- Is this limited life time infrastructure depending ?
- We found

- 	- Not applicable for exit gas flow if wet gas scrubbers
- 	- Limited lifetime in full exhausting air stream
- 		(at DESY 1200m3/h  24h a day 365 day / year)
- 	- looks like limited lifetime due to dust from dry HF absorbent

- TTC meeting Frascati Dec. 05   A.Matheisen DESY

##    All other sensors are very reliable

- Capacitive Sensor (Leak detection)
- Inductive Sensors (Position Sensors)
- H2 Sensor
- Read relay sensor ( level sensor)
- Gas sensors (O2 concentration)

- TTC meeting Frascati Dec. 05   A.Matheisen DESY

## Parameter control

- Optimized since last year
- Goal:
- 	almost constant current during the individual run
- 	stable temperature: better now
-  		but still needs better heat exchanger
- 		New type under development

- TTC meeting Frascati Dec. 05   A.Matheisen DESY

## Parameters of “final” Ep for vertical test 

- Parameters of “final” Ep for vertical test

- Warm up

- TTC meeting Frascati Dec. 05   A.Matheisen DESY

## Actual parameters - even valid for long runs during removal of damage layer  

- Actual parameters - even valid for long runs during removal of damage layer

- Warm up

- TTC meeting Frascati Dec. 05   A.Matheisen DESY

## DESY EP parameters

- TTC meeting Frascati Dec. 05   A.Matheisen DESY

## Sulfur and Corrosion

**Strong corrosion on AL electrode found**
**Strong sedimentation of Sulfur in the DESY  EP**
**Strongest sediment layer of S found in outlet pipe and sump**
**Small amount found in inlet pipe**
**Non found in heat exchanger outlet towards storage vessel**
**Removal of S from samples by alcohol successful**
**Removal of S from cavities by alcohol** **after EP prepared **
**	****	****system needs to be commissioned an tested **

- TTC meeting Frascati Dec. 05   A.Matheisen DESY

## Q disease

- Hit cavities several times under various conditions and “standard” process
- 	after 800 C 		Z84 --   Ac 71    --    P-1
- 	after 1400 C 		Z84  --   Z82

- Process parameters controlled online do not show differences
- between cavities with and without Q disease
- Infrastructure was not changed in between !

- Several cavities did not show Q problems even after
- System interrupts and  non regular processes
- Even when  filled with acid at T > 30 C for up to 30 minutes

- First time a serious of three in one preparation champagne !

**Problem not understood and no observable parameters found**

- TTC meeting Frascati Dec. 05   A.Matheisen DESY

## Z82 BCP after 1400 C

**Z83 BCP after 1400 C**

- TTC meeting Frascati Dec. 05   A.Matheisen DESY

## Z 82 after 1400 C 

**Z 82 after 1400 C **

**Z 83 after 1400 C**

- TTC meeting Frascati Dec. 05   A.Matheisen DESY

## Z82 

- Z82
- after
- 1400 C

- Z83
- after
- 1400 C

- TTC meeting Frascati Dec. 05   A.Matheisen DESY

## Slide 23

- TTC meeting Frascati Dec. 05   A.Matheisen DESY

## Q disease on 

| 29.09.2005 |   |   | neues Fass |
| --- | --- | --- | --- |
| 04.10.2005 | 120 min | Z84 | ohne Probe/ Sequenz übersprungen da G4 zu hoch |
| 06.10.2005 | 90 min | AC71 | ohne Probe |
| 10.10.2005 | 180 min | Z82 | ohne Probe |
| 17.10.2005 | 60 min | AC71 | ohne Probe |
| 24.10.2005 | 120 min | Z84 | ohne Probe                                                          |
| 31.10.2005 | 120 min | Z82 | ohne Probe                                                          |

**That’s all we found so far what the cavities with**
** ****Q disease have in common ( but only here !)**

- Print out of DESY log book

**Q disease on **
**Ac 71    Z84    Z82**

- TTC meeting Frascati Dec. 05   A.Matheisen DESY

## Mysteries

- We learned that acid mixture is not acid mixture !!
**That’s what you expect**
**H2 SO4 +HF <-> FSO3H H2S **+ **H +H2O +HF +X Nb?**

**Mysteries**

**That was found in “a bad acid” delivery in summer 2005**
**H2S **+ **H2 SO4 +HF <-> F2O2S+H2O +HF(< 0.1%) +X Nb??**

- TTC meeting Frascati Dec. 05   A.Matheisen DESY

## •But Cavity result looked good (35 MV/m )

- •But U- I measurements look fine in respect to all other barrels 
- •But standard analysis “titration of acid “ looked fine 
- But EP data looked normal
- • only EP apparatus HF exhausting >>>3ppm after 35 min

**According to Measurements by G . Kreps there was**

- Strange mixture still under investigation

- No change in fo

- No change in field profile

- No change in cavity length

- But 35 MV/m

- TTC meeting Frascati Dec. 05   A.Matheisen DESY

## Finally 

-  are  loaded by the following projects

- but it is limited   --  projects have different goals

**Finally **

- XFEL statistic / parameters / manuals
- VUV FEL  Module 6 ( Module 7 )
- CARE  EP on multi cell cavities
- High gradient ILC / parameters and high gradient module

-  There is synergy

**Load is put on 10 people**

- Do we pay for that load or can we serve for all projects  without loosing much?

- That’s the prototype for the XFEL we need people to help us
- to understand whats going with our parameter set

- TTC meeting Frascati Dec. 05   A.Matheisen DESY