Helium Gas Cryogenic Cooling System

The University is soliciting prospective proponents to submit proposals for a Helium Gas Cryogenic Cooling System.

The Helium Gas Cryogenic Cooling System will be used to cool a laser amplifier. The laser crystals, which need to be cooled to ~90 K, are mounted on cold fingers located in a vacuum chamber, which itself needs to operate at ~ 90 K. The low-temperature helium gas from the proposed Helium Gas Cryogenic Cooling System runs through the cold fingers. The thermal load generated by the laser crystals is 600 W. The helium transfer line should not cause large vibration to the cold finger. The stability of the temperature should be less than 10 K. The coolers must operate without using liquid nitrogen. The instrument must operate for 24 consecutive hours; 7 days per week (24/7), outside of planned shutdowns for annual maintenance.

In the cooling system, helium gas is cooled at the cold head to ~90 K and transferred into the helium cycling pump for pressurization. The low temperature helium gas will then be outputted onto the laser crystals for one-way cooling. The returned helium is then cooled down again for cycling.

The cold finger on which the crystals are mounted are supplied by the University. The pressure drop is 15 to 30 kPa. The University will also be supplying the cryostat vacuum chamber. The interfaces for the helium transfer line to the cold heads is UHV Flange. 

Mandatory Requirements:

1. Helium Gas Cryogenic Cooling System
1.1 Proposed solution must be composed of one (1) unit with a maximum cooling power using circulated helium gas of 500 W or higher at 90 K at the cold head.
1.2 The cold finger must reach ~80 K (+/- 10 K) within 3 hours.
1.3 The cold finger must run continuously at ~80 K (+/- 10 K) wihout the use of liquid nitrogen.
1.4 Cold finger temperature fluctuation must be ≤10 K under a full thermal load (150 W at cold finger) once the temperature has been set at 80 K.
1.5 Cold finger peak-to-peak vibration stability must be ≤ 100 nm.
1.6 The cold heads and compressors must be capable of being located up to 25 ft away from the cold finger. All connectors (tubes, hoses, other) must be a minimum of 40 ft in length in order to achieve this distance without impeding movement in the lab space.
1.7 The proposed solution must be capable of full automation during cooldown, temperature stabilization and warmup.
1.8 The instrument must be able to operate for 24 consecutive hours; 7 days per week (24/7), outside of planned shutdowns for maintenance once per year.
1.9 The compressors must operate on 480 V, 3 phase, 60 Hz power. The maxium power must be ≤36 kW.
1.10 The compressors must be water cooled.  Regardless of the solution proposed, the total flow must not exceed 12 Gallons per Minute (GMP) at 15C.

2. Other Requirements
2.1 A minimum of online video conferencing/Telephone conversation assistance must be included for installation by the user.
2.2 Must include a minimum of three (3) days of virtual training for a minimum of three (3) users. A day is defined as eight (8) hours with a one (1) hour lunch.
2.3 Must include a minimum of one (1) year of warranty on parts and labor.

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