IHEP 1.3 GHz Cryomodule and Cryogenics IHEP Cryogenic group 2nd Workshop of the IHEP 1.3 GHz SRF R&D Project Dec 2 nd, 2009

Outline Cryogenic test scheme of 9cell cavity Design of vertical test cryostat Design of horizontal test cryostat

Block Diagram of Cavity Test Cryogenic system Recovery and Purify system Vacuum PumpCollection BoxHeater 2KValve Box4KValve Box 2000L Dewar Cold Box 500W 4.5K compressor Horizontal Cryostat Vertical Cryostat

Three Methods of Obtaining 1.8K Superfluid Helium Direct pumping Pumping & Throttling Pumping & Throttling & Pre-cooling

Direct Pumping m (hL1 一 hL2 )+(hG1— hG2)(mL1-mL2 )=r (mL1-mL2 ) Liquefaction rate 59.8% IHEP old vertical test system position1980mm Effective height 2200mm2500mm Bottom of baffle Heat load9.14W15.87W19.35W Pumping 1.8K 16mbar Vertical test Dewar

Pumping & Throttling h 1 =h 2 =h 2 G x +h 2 L(1-x) mh 2 +Q=mh 4 Liquefaction rate 60% 3 Pumping Storage Dewar 4.2K 1.0bar 1.8K ， 16mbar 1 24 JT Vertical test Dewar

Pumping & Throttling & Pre- cooling 3 PumpingStorage Dewar 4.2K ， 1.0bar 1.8K ， 16mbar JT 6 T 5 （ K ） Liquefaction rate61%80%87.7% Vertical test Dewar Heat exchanger

TESLA cavity: R/Q=1036Ω, L=1.038m Vertical test –35MV/m, Q=8×10 9 –P loss =160W Horizontal test –31MV/m, Q=1×10 10 –P loss =100W Heat loads of the 9cell Cavity Test

Pump Selection Assume the heat loads 100W. Without considering the pressure drop between Dewar and vacuum pump. 300k, 16mbar, density of helium gas is 2.57×10 -3 Kg/m 3 Method1Method2Method3 Mass flow rate (g/s) Pumping speed (L/s) KEK-STF Cavity Loss is about 100W at the max. field in V.T. Compressor limit is 1200m 3 /h~333L/s Need to be discussed

Comparison of Three Methods Direct pumping The structure is simple. Bigger test Dewar is needed for the storage of much more LHe to keep the test time longer. Otherwise, the process need be stopped to refill LHe. Pumping & Throttling No heating exchanger and low efficiency. Pumping & Throttling & Pre-cooling Need more instrumentations and bigger investment. Test process is stable. Sensible heat of 1.8K Helium gas can be used, leading to higher liquefaction rate.

Pre-design of 9cell Cavity Test Cryogenic System Heat exchangerHorizontal test cryostat Vertical test cryostat

Vertical Test Cryostat FNAL vertical test cryostat

IHEP Vertical Test Cryostat

Vertical Test Cryostat Flow Chart

Progress of Vertical Test Cryostat Components’ 3D models have been finished and the assembling model need to be checked; Key materials have been counted; Standard components’ selection and layouts are under doing and design ( throttling valves, safety valves, hose- burst valve, temperature sensors, pressure sensors, standard cryogenic connectors); Key part heat exchanger is under design and need further discussion with FERMILAB; The first version of drawings is planed to be finished at the end of this year;

Horizontal Test Cryostat Single 9cell cavity horizontal test cryostat with length of 1800mm and diameter of 966mm; Cross-section almost the same as EXFEL cryomodule; A 300 mm He Gas-Return-Pipe (GRP) acting as support structure, together with 2 adjustable posts on top of the vacuum vessel. One post is the fixed- point, the other post can slide in longitudinal direction; A 1.8 K forward line transferring single phase helium, a 1.8 K two phase line connected to the cavity helium vessels, a 4-8 K forward and return line, a 40/80 K forward and return line, and a warm-up/cool-down line with capillary to the bottom of cavity vessel; Aluminum thermal shields with stiff upper parts for 4/8K and 40/80 K are attached to the support structure, with 10 layers and 30 layers of super- insulation (MLI) for 4/8K and 40/80 K respectively; In the end of cryostat, there is a small helium vessel with a liquid level meter inside, which is connected with He GRP and 1.8K supplying line of 9cell cavity. The cavity can be kept in the 1.8K LHe by monitoring the liquid level meter.

Horizontal Test Cryostat

Horizontal Test Cryostat Flow Chart

Progress of Horizontal Test Cryostat Structure design has been finished; Model design is nearly finished; POST support is under design; Parts of components’ structure need to be improved; The first version of drawings is planed to be finished at the end of this year.

Next Years’ Plan Complete the thermal dynamic simulation analysis; Finish the drawings of vertical Test cryostat and horizontal Test Cryostat and put into machining; Complete the whole flow chart of the 9cell cavity test cryogenic system; ………….

Thanks