This page describes the standard procedure for finishing a HODACA experiment and preparing the instrument and sample environment for the next user.
Please begin the handover procedure early enough that the next experiment can start smoothly.
As of October 2026, the standard HODACA user changeover time is 14:00.
We normally ask the outgoing users to finish measurements by approximately 13:30 so that there is enough time to complete the sample-environment shutdown and cleanup, tidy the experimental area, and complete the handover.
If a low-temperature sample environment must be warmed up for the next user, measurements may need to finish substantially earlier.
If the same sample-environment equipment is not required immediately after your experiment, it is generally not necessary to warm it to room temperature before the end of your machine time. In this case, measurements may continue until the end of the allocated machine time unless otherwise requested by the instrument staff.
If the next user will use the same refrigerator immediately, please begin warming it sufficiently early for sample exchange.
If the next user will use the 4 K GM refrigerator immediately after your experiment, please begin warming it sufficiently early for sample exchange.
At the start of the warm-up:
te 300
Set the temperature controller to 300 K and switch off the 4 K GM compressor manually.
The following warm-up times are practical guidelines based on experience at HODACA rather than guaranteed values.
If the refrigerator is near its base temperature, approximately 3 K, please start warming it about 1.5 - 2 hours before the scheduled user changeover.
The indicated sample temperature typically takes about 30 minutes to rise from the base temperature to approximately 300 K. However, additional one hour is required for the sample holder and other cold components inside the refrigerator to warm sufficiently for sample exchange.
Actual warm-up times depend on the sample, sample holder, thermal contact, and refrigerator condition. These times are therefore guidelines rather than strict requirements, but starting the warm-up with sufficient margin helps ensure a smooth user changeover.
If the 4 K GM refrigerator is not required immediately after your experiment, it does not need to be warmed to room temperature before the end of your machine time. You may continue measurements until the end of the allocated machine time unless otherwise requested by the instrument staff.
Before leaving HODACA, please make sure that the experimental area is ready for the next user.
Remove personal items and unnecessary materials from the desk and surrounding area. Save or copy the required experimental data, and update the experiment notebook with the final measurement status and any information that may be useful for the next user or instrument staff.
Please also assist with sample-environment cleanup and preparation when requested by the instrument staff.
Measured samples are kept in the C1-1 sample storage cabinet after the experiment.
If the installed sample environment is not needed immediately by the next user, the sample may be left installed. The sample will be removed when the sample environment is next required and will then be transferred to the C1-1 sample storage cabinet.
Neutron-irradiated samples must not be removed from the Guide Hall until the required radiation survey and removal procedure have been completed.
The time required before a sample can be released depends on the sample composition, neutron-activation properties, irradiation time, and total neutron exposure.
Once the radiation level has decreased sufficiently and the required release procedure has been completed, the sample can be taken out of the Guide Hall.
If you would like your sample to be returned by shipment after it has been released, please contact the HODACA instrument staff.