1. GTK gas coolingsystem status Marco Statera, Vittore Carassiti, Ferruccio Petrucci, Luca Landi NA62 - GTK working group meeting 12-7-2011

2. OUTLINE installation gas cooling system working parameters Na62 GTK working group meeting 12-7-2011 Marco Statera1

3. installation three separate cooling stations two trenches are fine, three are better short lines: cheaper – lower losses installation side: Jura - Saleve 2NA62 GTK working group meeting 12-7-2011 Marco Statera

4. SCHEME - liquid Pro liquid is a reserve of gas fast restart time after an emergency stop SHI CH-110 coldhead 170W@77K (+20%) Cons needs cryogenic liquid pumping vapour (not only gas) COST cryostat about 10k€ engineering,blower and DC controller: 140k€ cold head 16k€ lines about 15 k€ delivery 9 months 3Na62 GTK working group meeting 12-7-2011 Marco Statera

5. SCHEME – gas only Pro More flexible gas temperature selection No liquid involved Gas selection (He or N2) Higher flow possible Cons refill by outer bottle time between emergengy stop and restart pressure 3-4 bara COST vacuum, heat exchanger and pump 70 k€ cold head 16 k€ lines about 15 k€ delivery 5 months 4Na62 GTK working group meeting 12-7-2011 Marco Statera

6. COST REDUCTION different suppliers engineering and design (vacuum, cryogenics, heat exchanger …) Investigate a hybrid solution 5Na62 GTK working group meeting 12-7-2011 Marco Statera

7. TYPICAL MEASUREMENT cooldownmeasure warm up FLOW Ta Tc Tb 6Na62 GTK working group meeting 12-7-2011 Marco Statera Nov 2010

8. COOLDOWN May 2011Celsius – l/min seconds manual regulation the system is sensitive to flow regulation a heater at the GTK inlet can regulate the lower temperature about 20 °C below the temperature during operation even a 100 °C gradient introduces a maximum offset of 7Na62 GTK working group meeting 12-7-2011 Marco Statera material α 10 -6 1/K Aluminum22 Kapton20 Silicon5 Copper17 G10 – FR411

9. WARM UP self warm up – cooling turned off max warming speed about 40 K/h heating not required 8Na62 GTK working group meeting 12-7-2011 Marco Statera Nov 2010

10. emergency about 25 seconds with the valve closed: temperature rise 4 K/s @25 seconds power is stopped no need of very fast interlock: about 1 second 9Na62 GTK working group meeting 12-7-2011 Marco Statera May 2011

11. CONCLUSIONS gas cooling systems can be installed in the cavern comparison of different cooling system cost analisys of the gas cooling systems standard cooldown and warmup data and procedure shown emergency state parameters were investigated: response time ≈ 1 second Na62 GTK working group meeting 12-7-2011 Marco Statera10