Run coordinator report March 23 – 30, 2011 Brad Sawatzky JLab MCC 1:30pm Meeting March 30, 2011 Q weak

Summary (Short version) Fixed bad vacuum in beamline downstream of target  We went down Saturday, March 19 with a bad vacuum in the downstream beamline.  Leak checking was hampered / delayed by high activation near the dump. Upstream checked early on, downstream had to wait.  Extensive leak checking up and down the line made difficult by the poor vacuum, RGA doesn't work well found large leak at seal on downstream bellows flange, (partially) resealed when 3 bolts were tightened near the 1 o'clock position.  Ended up replaced the gasket at that flange.  Best theory is that small-angle Mollers are being swept into the flange by the QTOR field and heating it up. Thermal cycling eventually opened a leak.  Estimate is that there is roughly 1 kW being dissipated in that region. Added thermometry to affected flanges. Added air and water cooling to those flanges. We ran smoothly last night at full current.  Vacuum is good. Temps are stable. Beam looks good.

Beam Spot at dump w/ QTOR at 2.0 kAmp ● QTOR is steering the beam to some degree. ● At low field the beam starts at lower-left on the dump viewer. ● (The double-spot is apparently an artifact of the camera system.)

Beam Spot at dump w/ QTOR at 8.9 kAmp ● Roughly 2cm shift toward upper right. ● Jay attempted to find a magnetically neutral trajectory. No Luck. ● Best indications are that this shift has been there since summer. Can not find ELOG to verify one way or the other.

Dump bellows in Hall C Photo is taken from beam-left side of the dump platform. The bellows is made of SS, located immediately downstream of the giant (Al) flange on the right of the photo. Air cooling provided by fan (shown) Water cooling is copper piping wound around perimeter of each flange and connected to dedicated chiller. Thermometry added to all four flanges – Downstream bellows, & Al flange each have TCs at 3, 7, 11 o'clock (as viewed by beam) – Upstream bellows & Al flange have 1 TC each, positioned at 11 o'clock BEAM

Dump bellows in Hall C Photo is taken from beam-right side of the dump platform, looking upstream. Water cooling is copper piping wound around perimeter of each flange and connected to dedicated chiller. Visible thermometry are the 3 o'clock TCs on the downstream SS bellows flange, and the upstream flange of the Al spool

Temperature Plots (75 uA, air cooled only) Peak temperature is at 3 o'clock on downstream bellows flange (SS). Roughly 68–70 C.

Temperature Plots (75 uA, air+water cooling) Peak temperature is at 3 o'clock on downstream bellows flange (SS). Roughly 53 C.

Temperature Plots (75 uA, air+water cooling) Effect of QTOR on / off DS bellows flange: temp3 is 3 o'clock, temp1 is 11 o'clock QTOR OFFQTOR ON

Temperature Plots (150 uA, air+water cooling) Running from Wed OWL shift at full production current. Temp plateaued at 85 C, vacuum continues to improve.

To Do List Production! – Monitor bellows temps and vacuum. Will stop and investigate if temps rise, or downstream vacuum starts fluctuating significantly. – Beam quality is being looked at as we speak, so far things look very good! Moller on Thursday or Friday (TBD) Long term (6 mon. down) – modify beamline in this region to address the observed radiation and thermal load. Thanks! Thanks! Great support from Ops, Vacuum group, Hall C Techs, Radcon, MCC engineering group, and others I'm probably forgetting... Beam quality looks good too, keep your fingers crossed!

Thermocouple position map