Products

Liquid Nitrogen

VPF Series Cryostat Systems - Sample in Vacuum

Overview

Click button below to enlarge view of VPF liquid nitrogen cooled variable temperature pourfill cryostat with sample in vacuum, Janis Research, cryogenic equipment

Simple and inexpensive, the VPF cryostats provide a variable temperature sample environment with no valves or adjustments required.  Designed with versatility in mind, the VPF cryostat is field-upgradeable with additional feedthroughs, windows or sample holders should experimental requirements change.  Models for operation to 500 K, 700 K or 800 K are available.

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Standard Configuration

Click image to enlarge view of model VPF-800 liquid nitrogen pourfill cryostat from Janis Research.The Janis VPF cryostat is an inexpensive liquid nitrogen cryostat offering operating temperatures from 65 K to 800 K. Simple to use and refill, the VPF system uses a thermal impedance displacer and built-in heater to provide variable temperature capability. Temperatures below 77 K are achieved using an optional pumping manifold. High temperature capability is provided using special sensors and heaters.

Click button below to enlarge view of mechanical drawing of Janis Research model VPF-100 liquid nitrogen cooled cryostat with sample in vacuum, cryogenic research equipmentEnlarge

VPF Mechanical Drawing

Access to the sample compartment is provided by a quick disconnect clamp. Samples are mounted in a 3" diameter vacuum space (2.5" for VPF-800) and can be connected with cryogenic-service wiring (single conductor or coaxial). The four-way optical sample chamber (with a numeric aperture of 1.0) can be configured for reflectance or transmission measurements. Standard windows are fused natural quartz offering transmission from the UV to near- IR regions. Optional window materials can be installed to span the far/ mid- IR, VUV, and x-ray regions for a variety of spectroscopic measurements. An optional refill assembly permits refilling of the LN2 reservoir without affecting the controlled temperature.

Typical applications for the VPF include spectroscopy (photoluminescence, FTIR, UV- visible), materials characterization (resistivity, Hall Effect), as well as low- temperature imaging, microscopy, and component testing. Low cost, light weight, and portability make the VPF the ideal cryostat for multipurpose laboratories, demonstrations, and integration with existing instrumentation. VPF-100 and VPF-800 models are in stock for fast delivery to your site. (Contact Janis for delivery times on our Model VPF-100-FTIR cryostat.)

Custom configurations may be fabricated to fit restricted spaces (such as in a magnet system or spectrometer) or to allow the insertion of very large samples (such as semiconductor wafers or "cold plates" to cool several samples at once).

Standard Features:

  • Fused quartz windows
  • 4-way optical access (f = 1.0)
  • Si diode thermometer and heater (thermocouple for VPF-800)
  • Electrical feedthrough for thermometry
  • Optical sample holder
  • Complete system test

Optional Equipment:

  • Complete selection of ancillary equipment including temperature controllers, pumping stations, and storage dewars
  • Electrical measurement packages (sample holders, wiring, and feedthroughs)
  • Pumping manifold for <77 K operations (see Other Configurations tab)
  • Refill assembly for continuous operation
  • Sample holder for DLTS (see fixed probe sample holder on Other Configurations tab) 
  • Additional bottom warm window port and quartz window 
  • Special adaptor for use with SuperTran liquid helium transfer line (see Other Configurations tab)

Illustration of optical and resistivity sample holders from Janis Research

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Specifications

Initial cooldown time (to 77 K) 15 minutes
Temperature range (1):
VPF-100, S, ST 65-500 K
VPF-700S, ST 65-700 K
VPF-800 65-800 K
LN2 hold time:
77 K 5 hours (VPF-100[T]:  ~8 hours)
100 K 4.5 hours
200 K 2.5 hours
Typical stability (2) ± 50 mK
Vacuum level required (3) 10-4 torr
Approximate weight 7 lbs. (3.3 kg)
(1) Temperatures <77 K with optional pumping manifold
(2) Measured with temperature controller
(3) Vacuum pressure measured at room temperature prior to adding cryogens

Other Configurations

Click on image to enlarge view of fixed probe sample holder for applications such as DLTS, Janis ResearchClick image to enlarge view of fixed probe sample holder used for applications such as DLTS, Janis Research

Fixed Probe Sample Holder

Click on image to enlarge view of optional refill assembly for VPF cryostats, Janis Research, cryogenic equipment

Optional Refill Assembly for VPF Cryostats

Click image to enlarge view of VPF-100 with special 2.62" diameter clear view window, Janis Research, cryogenic research equipment, liquid nitrogen cooled pourfill cryostat, reference 13917

VPF-100 with Special 2.62" Diameter Clear View Window

Click on image to enlarge view of special VPF-100 with compact sample area for use in electromagnet. Reference 10465

Special VPF-100 with Compact Sample area (1") for use in Electromagnet

Click image to enlarge view of special VPF-100 with compact sample area (0.5") for use in electromagnet, Janis ResearchClick on image to enlarge view of special VPF-100 with compact sample area for use in electromagnet, Janis Research, cryogenics

Special VPF-100 with Compact Sample Area (0.5") for use in Electromagnet

Click image to enlarge view of Special VPF-700ST sub-compact, high temperature, non-optical liquid nitrogen variable temperature cryostat with special 4-probe sample holder, high temperature wiring installed, and a 10-way BNC breakout box, Janis Research, cryogenic equipment

Special VPF-700ST Sub-compact, High Temperature (700 K Only), Non-optical System
The system shown on the right has a special 4-probe sample holder, high temperature wiring intalled, and a 10-way BNC breakout box.

Click image to enlarge view of special adaptor that allows VPF LN2 cryostat to be used with model FHT-ST liquid helium transfer line. Janis Research, cryogenics.Click on image to enlarge view of photo of VPF LN2 cryostat attached to FHT-ST LHe transfer line, Janis Research, cryogenics

Special Adaptor Allows VPF Cryostat to be used with a SuperTran Liquid Helium Transfer Line
The VPF is normally a liquid nitrogen only cryostat. This special adaptor allows customers to run their existing VPF with liquid helium by connecting a standard inventory FHT-ST line to the fill port of the VPF cryostat. The base temperature is then extended to ~10 K. Purchasing an adaptor and a standard FHT-ST can be more cost effective than purchasing a complete ST-100 cryostat. 

Click image to enlarge view of VPF-100 with black anodized mounting flanges to interface with Jobin Yvon Fluorolog-3.Click image to enlarge view of VPF-100 with black anodized mounting flanges.

VPF-100 with Black Anodized Mounting Flanges
VPF-100 with mounting flanges for interface with Jobin Yvon FluoroLog®-3 spectrofluorometer

Click image to enlarge view of VPF-700S compact liquid nitrogen pourfill system

VPF-700S Compact System

Click image to enlarge view of VPF-100 with re-entrant window.Click image to enlarge view of VPF-100 with re-entrant window. This image shows the view from the inside.Click image to enlarge view of re-entrant window which was used for a VPF-100 LN2 cryostat.

VPF-100 with Re-entrant Window

Click image to enlarge view of VPF pumping manifold.

Optional Pumping Manifold for <77 K Operations

Click image to enlarge view of VPF with dual reservoir.

Special Dual Reservoir VPF System
This special dual reservoir VPF system allows the user to freeze the liquid nitrogen in the outer reservoir to keep the inner reservoir from boiling. This prevents bubbles from forming in the sample area that could otherwise cause problems for optical measurements.

Click photo to enlarge view of standard window block with countersunk screw holes. This particular photo shows a VPF-800, reference 16480, that was installed in the sample compartment of a spectrometer. The sample compartment is rather small and standard pan-head screws on the window block would not have allowed the system to fit in the small space, thus countersunk screw holes were used to allow for flat head screws.

Standard Window Block with Countersunk Screw Holes Option
Janis Research usually uses pan-head screws on the retainers of window blocks, which add about 0.125” to each side of the window block. In cases were space is an issue, talk to your sales engineer about countersunk screw holes in the retainers so that flathead screws can be used, as shown in this photo. This option can be offered on most window blocks with o-ring sealed windows. The window block shown can be used on our model VPF-100, VPF-800, ST-100, CCS-150, CCS-100/202, CCS-100/204 and SHI-4-2.

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