Dear Todd,

I have results for the first of two cases I'm simulating. In this case the cooling jet pipes axes are aimed at the center of the glass cell windows.
4He cooling jet agent, 30 uA beam current:

cooling agent Vdot:  0, 5, 10, 20, 40 (liters/min)
maximum temperature in glass cell beam nipples with 4 jets: 710, 698, 684, 636, 560 (K)
maximum temperature in glass cell beam nipples with 2 jets: 710, 667, 611, 537, 462 (K)

where 4 jets means that there are 2 jets aimed at the upstream (US) and 2 jets aimed at the downstream (DS) glass cell beam nipples respectively, and 2 jets means that there is one jet aimed at the US and one jet aimed at the DS glass cell beam nipples respectively (the jets on the RHS of the beam line looking DS along it are ON and the ones on the left are OFF/blocked). 

One more thing to help compare apples to apples (more or less): the same volume rate is divided 4-ways when all 4 jets are ON and 2-ways when only 2 jets are ON. At a Vdot = 10 liters/min the cooling flow average velocity coming out of a jet is 22 m/s for 4 jets and about 44 m/s for 2 jets. Still, if one compares 4-jets at, say, 10 l/min, v_jet = 22 m/s with 2-jets at 5 liters/min, v_jet = 22 m/s, the single jet is more efficient at cooling the beam nipple than 2 jets are.

I did a cursory check considering the cooling agent to be N2, 2 jets, 10 liters/min flow, Tmax ~ 647 K. (In the same conditions with 4He, Tmax is 611 K).

Conclusions from this case: 2 jets are better than 4 jets and He is a better cooling agent than nitrogen.

In about a week I should have results for the second orientation of the cooling jets. 

I cannot attend the meeting tomorrow (or any Tue at 2:30pm) as it overlaps with the MOLLER project management weekly meeting,


Kind Regards,

Silviu