Loadlock
=================================

The loadlocks for both endstations have 6-slot carousels. While heating was originally possible in the loadlock, in 2023 the carousel was replaced with a simpler design that does a much better job at not dropping samples, but does not permit sample heating.

The carousel can be continuously rotated with a manual knob at the bottom of the chamber:

.. image:: /_static/loadlock/carousel.jpeg
  :width: 400
  :align: center
|

On the A endstation, venting or pumping the loadlock is a one-button task from the 'ARPES Control panel' window on the endstation PC

.. image:: /_static/loadlock/interface.png
  :align: center
|

It typically happens when venting that the N2 inlet is closed slightly too early and the loadlock remains in a weak vacuum. In this case you can either gently pull/pry a little on the door to get it open, OR manually re-enable the N2 venting. Right click on the loadlock turbo pump icon in the control panel to gain buttons for this. Don't forget to disable ventilation again before trying to start the pump down macro.

.. image:: /_static/loadlock/manual_vent.png
  :align: center
|

A special tool (shown below) is required to insert and remove samples via the viton-sealed door. It typically lives in the BLOCH workshop room. A staff member will show you how to operate it.

.. image:: /_static/loadlock/tool.png
  :align: center
|


Pumpdown time
--------------


=================   =========================   ============================
Pressure (mBar)     Fast turnaround (hh:mm)     Slow turnaround (hh:mm)
=================   =========================   ============================
1x10\ :sup:`-6`     00:15                       00:30
1x10\ :sup:`-7`     2:00                        3:50
1x10\ :sup:`-8`     22:00                       ??
=================   =========================   ============================

Measured February 2019. Quick means only the amount of time necessary to insert a sample. Slow means opened, then left vented with door pushed closed for 30mins

Base pressure without baking: 6x10\ :sup:`-9` mBar

We typically recommend waiting for a pressure of 5x10\ :sup:`-7` mBar or better before opening to the transfer chamber, which you should obtain within 1-2 hours.

..
  Heating
  --------


  Heating is currently performed through a Prevac HEAT3 power supply which is multiplexed to the different slots. This means that only one heater can be running at a time. The multiplexer control to select which heating slot is connected is also found on the same 'ARPES Control panel' window that has the vent/pump buttons.

  The resistive heating slots have thermocouples connected to the receiver. The design is nearly identical to the heater in the PrepSec chamber; see that page for calibrations and comments. Since the main purpose of this heater is degassing and the temperature control does not need to be precise, we usually operature the loadlock heater under PID control. This means you don't need to worry about the current<-->temperature mapping, just set the receiver temperature you want.

  For the resistive heating stages the maximum allowed temperature on the receiver is 600\ |deg|\ C; higher than this risks damaging nearby components. For the direct heating stages the maximum allowed current is 12A.



.. |deg|    unicode:: U+00B0