Low Temperatures

CCR – Closed Cycle Cryostats

The CCR is a top loading device. The sample tube is filled with exchange-gas. Temperature regulation is achieved by a sensor and a heater attached to the sample tube. The sample holder is in general mounted to a sample stick. Temperatures ranging from 3.5 K to RT can be regulated. To reach for temperatures above RT to 700 K the sample space has to be evacuated and a special high-temperature sample-stick has to be used (available for CCR 9-11 and JTC 1-4). For this case temperature control is provided by a heater and sensor mounted on the sample stick.

Specifications

	CCR 4-23	cct3, 6, 7	JVC 1-2	cct 4,5	cvt1 VTI
Common features
Temperature range (K), with exchange in sample gas	2,8 – 300	3 – 300	1.5 – 300	3 – 300	1.5 – 300
Extended temperature range (K), evacuated sample space and HT sample stick	T < 700 K	800	-	800	-
Cool down time of cryostat: 300 K – base temperature (h)	min. 2.5	min. 2.5	min. 0.7	min. 2.5	4
Cool down time for sample change with cryostat at base temperature (h)	< 1.5	< 1.5	min. 0.7	< 1.5	1.5
Dimensions				Sapphire windows
Diameter of sample space (mm)	< 50 and < 80	< 60	< 50	< 60	50
Height of sample space (beam window) (mm)	~ 75	~ 100	~ 50	~ 100	135
Available sample sticks
Standard stick for T (K)	< 300	< 300	< 300	< 300
High temperature stick for T (K)	< 700	800	-	800
Rotation sample stick to provide sample rotation with fixed cryostat position	available	manually	-	manually
Gas adsorption stick	available	-	-	-
High voltage stick	available	-	-	-
High pressure sample stick for gas pressure cells (max. 4 kbar)	available	-	-

CCI – Low Temperature Inserts

To achieve temperatures below 3K, low temperature insert (CCI) are available. The inserts work together with CCR type top loading cryostats.
Using 3He-CCI inserts, a base temperature of 450mK can be achieved. To reach a base temperature of 50mK the 3He/4He-CCI insert can be used.

Specifications

	CCl – ³He	JKC1-2 – ³He/⁴He
Temperature range	450 mK – 10 K	20 mK – 1 K
Cool-down time (h)	5	6
Diameter of sample space (mm)	30	30
Total height of sample space (mm)	145	100
Distance cold plate to beam level (mm)	106.5	80

CC – Closed Cycle Cryostats

The sample space of these liquid-cryogen free closed-cycle cryostats is inside the isolation vaccum. The thermalisation of the sample is achieved by the thermal conductivity of the sample holder and the cold-plate. To avoid temperature gradients a sample mounting with adequat thermal conductivity is needed. In case of sample with poor thermal conductivity, the usage of an exchange-gas (He) containing sample can or the use of a CCR-type cryostat should be considered.

Specifications

	CC 1-4	CC 5-6	CC -7-CCM	CC 8-10	cce1, 4, 5
Temperature range (K)	2.8 – 300	2.2 – 300	2.2 – 300	2.8 – 600	3.5 – 400
Cool down time 300 K – 2.8 K (h)	2.5	2	4	5	1.5
Cool down time 600 K – 2.8 K (h)	-	-	-	5	-
Diameter of sample space (mm)	60	10	55	< 138 (CC-8); < 55 (CC-9, CC-10)	20×20 360°
Total height of sample space (mm)	110	10	85	< 136 (CC-8); < 85 (CC-9, CC-10)	-

Cryostat Type ADR (Adiabatic Demagnetization Refrigerator)

This technology in combination with a closed-cycle-refrigerator pre-cooling system allows continuous operation between temperatures of 300K and 300mK. Likewise, through the one-shot operation mode, a temperature of even below 300mK can be reached.
In addition, an automatic sample loading system allows sample change in just a few minutes, minimizing precooling times. For these models, the maximum diameter of samples allowed is 30mm and a maximum length of 70mm.
The ADR cryostats have been specially designed for neutron scattering instrument, where the sample stage features an aluminium tail with a diameter of 180mm and 360° neutron access.
Currently MLZ has two units, which are operated by TUM and JCNS. The JCNS ADR will be available at the PANDA instrument as PANDAs new standard cryostat.

Specifications

	ADR Cryostat
Temperature range (K)	300 – 0,300
Cool-down time (h)	30
Cool-down time for sample change (h)	2,5
Dimensions
Diameter of sample space (mm)	30
Height of sample space (beam window) (mm)	70