IceTop freeze tests

Interim report from South Pole

December 2, 2003

South Pole 03/04 season

SPASE counting house

100 m

Location of two test tanks, Nov ‘03

Construction of tanks

• 2 Tanks delivered to Bartol in July; plumbing assembled

• Tanks & plumbing integrated, palletized and foamed at factory in VA late August

• Tanks arrive at Pt. Hueneme Sept 2

Freeze-control equipment & DOMs

• Freeze control assembled at Bartol August - October

• Shipped with support equipment Sept-Oct (including sunshades)

• 4 DOMs with rev2 boards assembled, tested, shipped from UW October 31

Two views of freeze-control equipment mounted on tank inside sunshade at site

Reassembly at South Pole• Gaisser, McDermott, Roth

arrive at South Pole Nov 10

• Used half of 40’x15’ heated Jamesway #76 in construction/cargo area

• Uncrated and assembled tanks near Jamesway; location convenient to logistical support

• Time: 2 persons, 1.5 weeks

• DOMs arrive Nov 15

Preparation of site

• In parallel with assembly– Locate & survey site– Excavating trenches: two

hours using bulldozer with 14’ blade Nov 18

– Trenches 15 ft wide by about 40 ft long

– Tanks separated by 10 m– Power cord from SPASE

supplied by RPSC Nov 19

Transport to site

• Nov 19– Load tanks on sled

– pull across skiway to MAPO

– Forklift from MAPO to site

– Level bottom of trenches

– Set & level tanks

– 3-man RPSC crew took a total of 2 hours

Install freeze-control & DOMs

• Tank10 (1.0 m ice)– Install freeze box

– Install ejection pipe

– Bring up software

– Install DOMs

– Nov 20-21

• Tank09 (0.9 m ice)– Same procedure

– Nov 25-26

Fill tanks

• Tank10– Freeze up of hose on

first attempt (Nov 21)

– Successful fill Nov 22• 20 minutes to fill

• < 10 RPSC man hours for transport and filling

• Tank09– Filled Nov 26, very

smooth operation

Monitor freezing

• Two days to freeze over– Frost-covered ice– Clear; wind 6-10 kts– T = -40 to -35 deg C– Ice-surface at -20 deg C

37 days to freeze 1 m• But Tank10 at 2/3 ideal rate• Will reduce heat tape, pump cycle

time, add fans to reduce freeze time

• Tank09: problems with temp sensors currently being addressed. No water ejected after 100 hours suggests slow leak. To be investigated. Ice appears good.

• Winter-over scientist will take over monitoring to bridge until arrival of next crew (J. Eisch, S. Yoshida)

Remainder of season

• Dec 1-5: train winter-over scientist (J. Lackey) and address problems

• Dec 10-30: Monitoring continues – S. Yoshida, Dec 10-31; J. Eisch Dec 20-Jan 6

• Dec 29-Jan 20: Install DOM-DAQ– J. Kelley, A. Karle with Evenson & S. Tilav

• Jan 12-27: Close tank– P. Evenson, Jan 12-27

Lessons so far

• Modularize equipment– “plug and play” design to reduce labor needs– Programmable Logic Control to streamline assembly and operation

• Should include temperature control of heat tape• Commercial OTS control units at each tank

– See memo of Andrew McDermott based on experience this season• Manufacturing schedule should be at least one season ahead to allow

shipping by vessel• Need full Jamesway (40 x 15 ft) for staging• Begin early in season with tank assembly• Counting house, surface cables required early to allow setting tanks• Tanks to be filled as soon as Rodriquez well for drilling is ready—should

not wait to be filled as each hole is drilled.