Solenoid Status Paul Brindza Dec. 12, 2003

Status of work at IUCF Solenoid R&R is based on a MOU between JLAB and IUCF The MOU divides the work into three Phases and a pause. Phase zero is measurement and investigation. This includes electrical measurements on each coil, instrumentation checkout, leak testing and pressure testing and mechanical measurements of the shields in coils 1 and 4.

Status of work at IUCF Phase one includes the rework of all four coils and final testing and evacuation. This includes replacement of the LN2 shields, repair of instrumentation and other internal work The pause is to allow time for getting the Model 2800 Helium refrigerator operational Phase two includes the replacement of "puffing billy" and the reassembly of the solenoid, new controls and instrumentaion and mating with the new power supply. At present Phase zero is near completion.

Phase zero measurements and results Coil electrical measurements Coil # Across Coil LH Lead - Ground RH Lead - Ground 14.9 O2.2 O6.4 O 23.2 OOPEN 32.7 O2.6 O0.2 O 45.2 OOPEN

Coil Inductances Coil 1 Coil 2 Coil 3 Coil mH 244 mH 172 mH 763 mH

Internal instrumentation and voltage taps Each coil has voltage taps (VT) and Carbon Resistance Thermometers (CRT) in the Helium vessel and Thermalcouples (TC) on the N2 shield and strain gauges (SG) on the support posts. Coil 1 Coil 2 Coil 3 Coil 4 VT OK OK OK OK CRT 7 of 8 OK OK OK 4 of 7 OK TC OK OK OK OK SG 3 of 6 OK 2 of 6 OK OK 3 of 6 OK Note: coil 4 has some extra CRT’s in unknown locations.

Leak testing and pressure testing N2 Shield He Vessel External Pressure tests Coil one 5 x 10 ^ -5 OK 12 inch bellows OK Coil two OK 2 x 10 ^ -6 OK OK Coil three 4 x 10 ^ -5 OK 12 inch bellows OK Coil four 4 x 10 ^ -6 OK OK OK Leak rates in torr-liter per second

Ongoing work for Phase zero Coils 1, 3 and 4 have been evacuated, backfilled dry and sealed. A search is on for the Helium leak in coil 2 The N2 shield has been removed to provide access The He vessel has been pumped to reduce background The He vessel will also be pressurized and "sniffed" The leak will be repaired by welding when found During the leak investigation further tests to locate the probblems with the strain gauges have been performed

Ongoing work for Phase zero All four coils have had conflat flanges added to all internal connections to permit high quality leak testing and to permit future connections without "cut and weld". The two damaged and leaky 12 inch bellows will be replaced. Attempts to repair have proven to be temporary The model 2800 helium refrigerator is indoors and is being prepped for shipment to JLAB The JLAB cryo group will perofrm a thorough checkout, some updating and a dry run To test the turbines. The new N2 shield design based on field measurements of coils 1 and 4 and original drawings is being finalized at JLAB in consultation with the manufacturer. The N2 coolant flow for the new shields has been evaluated. Potential modification to the "cake pan" coil covers is being evaluated with IUCF to provide better clearance for assembly and insulation

Cake Pan Modifications Cross section of coil 2,3,4

Status of Phase one A Scope of Work (SOW) and Purchase Requisition (PR) have been prepared The SOW and PR have been circulated at JLAB for signature Final approval is awaiting CD-0 The SOW has been sent to IUCF for comment. The Scope of Work includes the complete R&R of all four coils. This includes replacement of the LN2 shields, repair of any leaks, repair (if possible) of instrumentation, final evacuation and leak test, pressure test and dry storage until Phase two

Magnetic simulations of the upstream hole and an iron plug with varying gaps.

Bmod over a patch (-5 < Z < 80, 10 < R < 80 inches) 4 inch gap, max field.208 T, Integral B.dA = 132 Tesla inch^2

Bmod max on patch upstream

Integral Bmod over patch upstream

Bmod on patch with big hole

Bmod on upstream patch 4 inch gap with thin plug