The requirements for these types of clearances have changed drastically over the years. I had a TS/SCI while in the Air Force. I didn't have to go through an exhaustive investigation. And I didn't have to do polygraph. ( normally, nowadays they disclose if polygraph is required ).

I hold a current clearance. It involved SF86 and an interview ( which was a pain in the *** because they ask you about details from stuff decades old if it raises a flag ... I can barely remember last year, let alone details of things I'd rather forget .... ).

The biggest thing I hate about clearance jobs these days is the ANNUAL training. I have to take courses retired by 3 different organizations every year, most of which cover the same material. It's redundantly exhausting.

While the pay can be nice ... I wouldn't recommend a modern clearance job to anyone.  LOL

FYI -
   Getting a compartmentalized access security clearance in the US is time consuming, and expensive to process since they examine your background from today back through to your 18th birthday. In detail. Under special circumstances they go back even further (example: juvenile criminal record). You WILL be required to take a full scope + lifestyle lie detector test. You WILL undergo drug testing. You WILL be required to sign a NDA. Back in the day, the third sentence of the first paragraph of this NDA stated "The disclosure of classified information is deemed treason, and is punishable by death". This is utterly serious and is not a joke. The clearance must be updated every X number of years, and can be repeated at random. These forms are available online.

   The fastest successful clearance granted of which I am aware took 4 months, the longest one took 29 months. I am not kidding.

   The upside is you get to work on some  A M A Z I N G  projects, the downside is you now have an EBI/SCI clearance and there are places to which you may not travel, and you absolutely may not discuss the work with anyone, anywhere, EVER.

   If you like to get drunk, are a chatterbox, or cannot keep a secret, then don't apply for this kind of work.

FYI:  Nothing in this post is classified, you could find it out on your own with a little research.
More info:  https://en.wikipedia.org/wiki/List_of_U.S._security_clearance_terms
                https://www.dni.gov/files/NCSC/documents/Regulations/FORM%204414_Rev_12-2013_fillable.pdf
                https://news.clearancejobs.com/2021/10/25/how-long-does-it-take-to-process-a-clearance-q4-2021/

Hi Bruce;

  I hope that you have luck with this posting. If it's anything like Canada, Top Secret security clearance is super hard to get (I have had it twice before working for the Bank of Canada and the Supreme Court of Canada)!  TS clearance now requires ...

• Must be a Canadian citizen (US in your case).
• Must have a government department sponsor.
• Candidate must be vetted by CSIS (government security agency).
• A background check is also done by the RCMP
• CSIS must be allowed to have access to your personal information (ie: Bank Statements, Tax filings, etc).
• All your references (which you must supply a few) are all background checked & interviewed by CSIS
• A typical TS application can take 1-2 years to complete
• A TS clearance is only good for 5 years
• After 5 years, you must go through the entire process again.

How does that compare to the USA process (just curious)?

Regards ... Chris