GaAlAs sensors are discontinued. Please consider DT-670, Cernox®, and Platinum sensors as replacements.

GaAlAs Diode Specifications


Standard curve Not applicable

Recommended excitation 10 µA ±0.1%

Maximum reverse voltage (diode) 2 V

Maximum forward current (diode) 500 mA

Dissipation at recommended excitation Typical 50 µW max at 4.2 K, 14 µW at 77 K, 10 µW at 300 K

Thermal response time (typical) SD: <10 ms at 4.2 K; P and PL (discontinued): 100 ms at 4.2 K, 250 ms at 77 K, 3 s at 305 K

Use in radiation Recommended for use only in low level radiation — more information

Use in magnetic field Low magnetic field dependence when used in fields up to 5 T above 60 K — more information

Reproducibility1 ±10 mK at 4.2 K

Soldering standard J-STD-001 Class 2

1 Short-term reproducibility data is obtained by subjecting sensor to repeated thermal shocks from 305 K to 4.2 K

Range of use

 Minimum limit Maximum limit
TG-120-SD, CU-HT1.4 K500 K
TG-120-P, PL (discontinued)1.4 K 325 K

Calibrated accuracy

 Typical sensor accuracy2Long-term stability3
1.4 K4±12 mK ±25 mK
4.2 K4±12 mK±15 mK
10 K±12 mK±25 mK
77 K±22 mK±15 mK
300 K±32 mK±50 mK
500 K±50 mK

2 [(Calibration uncertainty)2 + (reproducibility)2 ]0.5 for more information see Appendices B, D, and E

3 Long-term stability data is obtained by subjecting sensor to 200 thermal shocks from 305 K to 77 K

4 Under 10 K calibration valid in vacuum only

Temperature response data table (typical)

 V (volts)dV/dT (mV/K)
1.4 K 5.3909-97.5
4.2 K4.7651-214
20 K2.5341-97.5
77 K1.4222-1.24
300 K0.8978-2.85
500 K0.3778-3.15

Expanded response table

Physical specifications

 MassLead typeInternal atmosphereLead polaritySensor materials
TG-120-SD 38 mg2 platinum, welded to package; CAUTION: leads are delicateHermetically sealed in vacuumPositive lead on right with package lid up and leads toward userChip mounted on sapphire base with alumina body and lid, Mo/Mn metallization on base & lid top with nickel and gold plating
TG-120-P (discontinued)79 mg2 phosphor bronze, insulated with heavy build PolyimideAirShort (+) Long (—)BeO ceramic header set into a gold plated copper cylinder
TG-120-PL (discontinued)20 mg2 platinumSolid epoxyShort (+) Long (—)Constructed with platinum, Stycast® epoxy, and alumina

GaAlAs calibration ranges


Typical magnetic field-dependent temperature errors5 ΔT/T (%) at B (magnetic induction)

Package base parallel to field B
T (K)1 T 2 T3 T4 T5 T

5 To minimize magnetic field-induced temperature errors, the sensor should be oriented so that the package base is perpendicular to the magnetic field flux lines — this results in the diode current being parallel to the magnetic field

TG-120-SD package TG-120-P package
TG-120-PL package