DESY experiences on assembly procedures for cavity - and string assembly Definition of work flow for string assembly @ DESY Example on critical operation Analysis of data Summary TTC Topical Workshop on SRF Cryomodule Clean Room Assembly CEA Saclay, 12th november 2014

DESY experiences on assembly procedures for cavity - and string assembly ---- Definition of work flow Cavity String = 8 Super conducting resonators (ready for installation) 8 beam connecting bellows (cleaned and leak checked) 2 Gate valves 1 Beam position monitor (BPM ) 1 superconducting quadrupole (pre cleaned and pre aligned) Step item 1 BPM 2 BPM to Quadrupole 3 Gate valve 1 to BPM 4 quality control of BPM /gate valve assembly 5 Gate valve2 to cavity 1 6 Connect cavity 1 to cavity 2 by bellows connection 7 Connect cavity 2 to cavity 3 by bellows connection 8 to 12 Connect cavity 3 to cavity 4 (4-5;5-6;6-7;7-8 ) by bellows connection 13 adjust coupler distance 14 Leak check of sub string unit 15 Connect cavity 8 to quadrupole assembly 16 final leak check of string

DESY experiences on assembly procedures for cavity - and string assembly ---- Definition of work flow cont. Power coupler is installed @ different station. (no cross contamination) Cavities come under vacuum for string assembly (final leak check and RGA just before assembly)

DESY experiences on assembly procedures for cavity - and string assembly ---Example for critical operation Most critical operation on cav or string assembly Opening / closing of flanges Particulates from slits or bore holes are hard to remove by cleaning for ISO 4 Nuts and bots bolts produce particulates when nuts are turned Generalized work flow for critical assembly steps on cav and strings Align cavity on rail and connect to TMP perform RGA and leak check Vent CAV to air pressure Start Argon overlay /(Flushing) Dismount flange connection Remove 4 studs from flange clean holes (<10 counts /sqft min) Insert cleaned new studs Remove remaining studs remove all studs and flanges and open flange Connect to next flange with Gas flushing overlay Install 4 cleaned studs and close connection hand tight

DESY experiences on assembly procedures for cavity - and string assembly ---Example for critical operation cont. Y Film 1

DESY experiences on assembly procedures for cavity - and string assembly ---Experiences from the past string assemblies at DESY At DESY string assembly was prototyping 2 types of Helium vessels 2 types of gaskets 3 types of Quadruple and Beam Position Monitors Several types of power coupler Limited space in ISO 4 area Assembly procedure and tools needed to be adjusted several times

DESY experiences on assembly procedures for cavity - and string assembly ---Analysis of data TTC meeting at Milano, March 04, 2010 Eiji Kako (KEK, Japan) D.Kostin (DESY Germany '

DESY experiences on assembly procedures for cavity - and string assembly ---Analysis of data cont. TTC meeting at Milano, March 04, 2010 Eiji Kako (KEK, Japan) D.Kostin (DESY Germany)

DESY experiences on assembly procedures for cavity - and string assembly ---Analysis of data cont. Eiji Kako (KEK, Japan)

DESY experiences on assembly procedures for cavity - and string assembly ---Summary At DESY string assemblies are done on prototype modules Some strings needed repair (Not met spec) Repairs were done successfully (by exchange of cavities of complete sub strings) In Module test degradation of cavities was seen after string assembly in resp. to vertical or horizontal test Some degradations can be explained by field emission Remark: At that time we had only 1 Xray detector (!) [cavity beam tube long side] Some showed Quench without indication of field emission Remark: this effect was also seen at KEK with complete different assembly sequence Analysis of data recorded did not give explanations for degradation (Degradation without field emission still not explained until now) Remark: When major errors happened cav was exchanged immediately to spare one! CAV with little degradation had lost of NC record in log book Cavities showing strong degradation had no logbook entries (?)

DESY experiences on assembly procedures for cavity - and string assembly ---Summary Open questions Do operators (Do they have a chance) to recognize the Non Conformance while doing the job ?