This assembly is the core of the Thermal Modulation System which consists of several sub-assemblies that we will now review.
The Head Clamp Assembly is included with the ZX1 and ZX2 Thermal Modulation Systems and is also available separately as a replacement module.
The Head Clamp Assembly consists of two subassemblies; the Head Clamp and the Hot Jet.
![Head Clamp Assembly: Head Clamp and Hot Jet Subassemblies](https://zoex.com/wp-content/uploads/2021/10/Screen-Shot-2021-10-14-at-12.25.52-PM-1024x651.png)
Key features of the Hot Jet Assembly are: a gas inlet port and a heater/sensor cable (shown here in partial view), which connects to a cartridge heater and a temperature sensor, housed within a heater canister.
![Head Clamp Assembly: gas inlet port, heater canister, heater/sensor cable](https://zoex.com/wp-content/uploads/2021/10/Screen-Shot-2021-10-14-at-12.27.07-PM.png)
A heated jet of gas exits the hot jet exit port on the right.
![Head Clamp Assembly: hot jet exit port](https://zoex.com/wp-content/uploads/2021/10/Screen-Shot-2021-10-14-at-12.27.47-PM-1024x592.png)
The head clamp assembly consists of the head clamp proper and two other parts: the clamping screw and the reducing collar. These last two parts secure the head clamp assembly to a cold jet transfer line as follows:
![Head Clamp Assembly: reducing collar, clamping screw](https://zoex.com/wp-content/uploads/2021/10/Screen-Shot-2021-10-14-at-12.28.31-PM.png)
The cold jet assembly engages with the head clamp assembly. Turning the clamping screw clock-wise clamps the two assemblies together.
![Head Clamp Assembly: clamping screw](https://zoex.com/wp-content/uploads/2021/10/Screen-Shot-2021-10-14-at-12.28.58-PM.png)
The cold jet assembly consists of an outer jacket and an inner conduit through which cool or cold gas flows.
![Head Clamp Assembly: conduit, jacket](https://zoex.com/wp-content/uploads/2021/10/Screen-Shot-2021-10-14-at-12.29.34-PM.png)
The jacket and conduit are separated (and thermally insulated) by a permanent vacuum space. Cool or cold gas exits through the cold jet exit port.
![Head Clamp Assembly: cool or cold jet exit port, vacuum space](https://zoex.com/wp-content/uploads/2021/10/Screen-Shot-2021-10-14-at-12.30.27-PM.png)
The column holder, which carries the modulator tube, slides into the head clamp. The apex or “extremum” of the so-called loop comes to rest at the intersection of the hot and cold jets.
![Head Clamp Assembly: column holder, loop](https://zoex.com/wp-content/uploads/2021/10/Screen-Shot-2021-10-14-at-12.31.07-PM-1024x621.png)
This view shows proper alignment between the modulator loop extremum and the center of the hot jet exit port.
![Head Clamp Assembly: loop extremum, hot jet exit port](https://zoex.com/wp-content/uploads/2021/10/Screen-Shot-2021-10-14-at-12.32.00-PM-1024x601.png)
This view shows proper alignment between the modulator loop extremum and the center of the cold jet exit port.
![Head Clamp Assembly: cold jet exit port, loop extremum](https://zoex.com/wp-content/uploads/2021/10/Screen-Shot-2021-10-14-at-12.32.54-PM-1024x583.png)
To learn more, contact Zoex: info@zoex.com